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Search for Scalar Charm Quark Pair Production in pp Collisions at v/s = 8 TeV with the ATLAS Detector G. Aad et al. (ATLAS Collaboration) (Received 6 January 2015; published 22 April 2015) The results of a dedicated search for pair production of scalar partners of charm quarks are reported. The search is based on an integrated luminosity of 20.3 f t r 1 of p p collisions at -Js = 8 TeV recorded with the ATLAS detector at the LHC. The search is performed using events with large missing transverse momentum and at least two jets, where the two leading jets are each tagged as originating from c quarks. Events containing isolated electrons or muons are vetoed. In an R-parity-conserving minimal supersymmetric scenario in which a single scalar-charm state is kinematically accessible, and where it decays exclusively into a charm quark and a neutralino, 95% confidence-level upper limits are obtained in the scalar-charm-neutralino mass plane such that, for neutralino masses below 200 GeV, scalar-charm masses up to 490 GeV are excluded. DOI: 10.1103/PhysRevLett. 114.161801

PACS numbers: 14.80.Ly, 12.60.Jv, 13.85.Rm

Supersymmetry (SUSY) [1-9] is a theory that extends the Standard Model (SM) and naturally resolves the hierarchy problem by introducing supersymmetric partners of the known bosons and fermions. In the framework of a generic /s’-parity-conserving minimal supersymmetric extension of the SM, the MSSM [10-14], SUSY particles are produced in pairs and the lightest supersymmetric particle (LSP) is stable, providing a possible candidate for dark matter. In a large variety of models, the LSP is the lightest neutralino, The scalar partners (squarks) of various flavors of quarks may, rather generally, have different masses despite constraints on quark flavor mixing [15]. Recent searches disfavor low-mass top squarks (stops), sbottoms, and gluinos, so direct scalar-charm (c) pair production could be the only squark production process accessible at the LHC. Searches for c states provide not only a possible supersymmetry discovery mode but also the potential to probe the flavor structure of the underlying theory. Since no dedicated search for c has previously been performed, the best existing lower limits on c masses are obtained from searches for generic squark and gluino production at the LHC [16,17], and from the reinterpreta­ tion of LHC searches [18] for direct pair production of the scalar partner of the top quark followed by decays ~t\ -* c + / f|. The top squark searches have a final state similar to that expected for scalar charm quarks, but are optimized for small m-t —m^o mass differences, and so have

*Full author list given at the end of the article. Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distri­ bution o f this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.

0031-9007/15/114(16)/161801(19)

good sensitivity to the scalar charm quark only when m-c —m^a < mw. In this Letter, a dedicated search for direct c pair production is presented. The scalar charm quark is assumed to decay dominantly or exclusively via c -* The expected signal is therefore characterized by the presence of two jets originating from the hadronization of the c quarks, accompanied by missing transverse momentum (£tpss) resulting from the undetected neutralinos. The ATLAS detector is described in detail elsewhere [19]. This search uses pp collision data at a center-of-mass energy of 8 TeV recorded during 2012 at the LHC. After the application of beam, detector, and data quality require­ ments, the data set corresponds to a total integrated luminosity of 20.3 fb-1 with a 2.8% uncertainty, using the methods of Ref. [20], The data are selected with a three-level trigger system that required a high transverse momentum (pT) jet and £jpss [21], While events containing charged leptons (elec­ trons or muons) in the search region are vetoed, single­ lepton triggers are used for control regions. Events are required to have a reconstructed primary vertex consistent with the beam positions, and to meet basic quality criteria that suppress detector noise and noncollision backgrounds [22]. Jets are reconstructed from three-dimensional topo­ logical calorimeter energy clusters by using the anti-k( jet algorithm [23,24] with a radius parameter of 0.4. The measured jet energy is corrected for inhomogeneities and for the noncompensating response of the calorimeter by using pT- and //-dependent [25] correction factors [26]. The impact of multiple overlapping pp interactions (pileup) is accounted for using a technique, based on jet areas, that provides an event-by-event and jet-by-jet correction [27]. Only jet candidates with p T > 20 GeV within j//| < 2.8 are retained.

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Electron candidates are required to have p T > 7 GeV, \tj\ < 2.47 and to satisfy “medium” selection criteria [28], Muon candidates are required to have p T > 6 GeV, |r\ | < 2 . 4 and are identified by matching an extrapolated inner-detector track to one or more track segments in the muon spectrometer [29]. When defining lepton control regions, muons and electrons must meet additional “tight” selection criteria [29,30], and must satisfy track and calorimeter isolation criteria similar to those in Ref. [31]. Following this object reconstruction, overlaps between jet candidates and electrons or muons are resolved. Any jet within a distance AR = 0.2 of a medium quality electron candidate is discarded. Any remaining lepton within AR = 0.4 of a jet is discarded. Remaining muons must have longitudinal and transverse impact parameters within 1 mm and 0.2 mm of the primary vertex, respectively. The calculation of £™ss is based on the vector sum of the calibrated p T of reconstructed jets (with pT > 20 GeV and \t]\ < 4.5), electrons, muons and photons, and the calorim­ eter energy clusters not belonging to these reconstructed objects [32], Jets containing c-flavored hadrons without ^-flavored parent hadrons are identified using an algorithm, optimized for charm tagging, based on a neural network that exploits both impact parameter and secondary vertex information and with a B to D decay chain vertex fitter [33], This algorithm achieves a tagging efficiency of 19% (13%, 0.5%) for c-jets (b-jets, light-flavor or gluon jets) in tt events. The efficiency for tagging fr-jets is determined from measurements of dileptonic ft events [34], The c-jet tagging efficiency and its uncertainty have been calibrated in inclusive jet events over a range of p T using jets from collision data containing D* mesons [35], Jets can be otagged only within the acceptance of the inner detector (\rj\ < 2.5), so only such central jets are retained after the above selection. Events are then required to have £™ss > 150 GeV and one jet with p T > 130 GeV to ensure full trigger eificiency, as well as a second jet with pT > 100 GeV. The two highest-/?x jets are required to be c tagged. The multijet background contribution with large £7J?1SS, caused by mismeasurement of jet energies in the calorimeters or by neutrino production in heavy-quark decays, is suppressed by requiring a minimum azimuthal separation (A)]2} I/2- The boost correction preserves the expected endpoint in the distribu­ tion against boosts caused by initial-state radiation. In the case of scalar-charm pair production with c -> c + 7 °, mCT is expected to have an endpoint at (m? - mla)/m-c. For ft Xi

production, if both 7>-jets are mistagged as c-jets, the mCT built using those two jets is expected to have a kinematic endpoint at 135 GeV. To maximize the sensitivity across the c-/j mass plane, three overlapping signal regions (SR) are defined: mCT > 150, 200, and 250 GeV. The remaining tt background after the mCT requirement mostly comprises events with one true c-jet from a W decay and a mistagged b-jet from a top quark decay. Events in which a Z boson is produced in association with heavy-flavor jets where the Z boson decays into vv also enter the high-mcx regions. The heavy-flavor jets often originate from a gluon splitting, g —>cc, which can lead to a small angular separation between the resulting c-jets and therefore a small invariant mass mcc. The remaining ft background is also concen­ trated at low mcc. Consequently, a final requirement selects events for which the invariant mass of the two c-tagged jets is larger than 200 GeV. Simulated-event samples are used to aid the description of the background and to model the SUSY signal. Top quark pair and single top production in the 5 and Wt channels are simulated with powheg-1.0 (r2092) [38], while the t channel single top production is simulated using AcerMC 3.8 [39]. A top quark mass of 172.5 GeV is used. The parton shower, fragmentation, and hadronization are performed with pythia -6.426 [40], Samples of W + jets, Z + je ts , and dibosons (WW, W Z, ZZ) with light and heavy flavor jets are generated with sherpa 1.4 [41], assuming massive b /c quarks. Samples of Z ft and Wft are generated with Mad Graph-5. 1.3.33 [42] interfaced to pythia -6.426. The signal samples are generated for a simplified SUSY model with only a single c state kine­ matically accessible, and with BR(c -*■ c+x®) = 100%, using M adGraph-5.1.5.11 interfaced to pythia -6.427 for the parton shower, fragmentation, and hadronization. Signal cross sections are calculated to next-to-leading order in the strong coupling constant, adding the resummation of soft gluon emission at next-to-leading-logarithm accuracy (NLO + NLL) [43-45]. The uncertainty on each nominal cross section is defined by an envelope of predictions using different PDF sets and factorization and renormalization scales, as described in Ref. [46]. The Monte Carlo (MC)

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samples are processed through a detector simulation [47] based on geant4 [48]. The effects of pileup are included in the simulation. Efficiency corrections derived from the data are applied to the simulation to correct for lepton efficiency as well as the tagging and mistagging rates. The main SM process contributing to the background after all signal region selections is Z + jets, followed by W + jets, top quark pair, and single top production. Most ft events contributing are ft -»■ bbfvqq events, in which either a r lepton decays hadronically, or an e or p is out of the geometric acceptance or not reconstructed or identified. Contributions from multijet, diboson, and asso­ ciated production of ft with W, Z are subdominant. Noncollision backgrounds are found to be negligible. The estimation of the main background processes is carried out by defining a set of three data control regions (CR) that do not overlap with each other or with the signal regions. The CRs are kinematically close to the SRs and each of them is enhanced in one or two of the backgrounds that is dominant in the SRs, while having low expected signal contamination (less than 1%). A statistical model is set up in which the background expectation in the CRs and SRs depends on several parameters of interest: the nor­ malizations of the dominant backgrounds, top (ft + single top), Z + je ts and W + jets, as well as on nuisance parameters including the effect of uncertainties on the jet energy scale (JES) and resolution, calorimeter resolution for energy clusters not associated with any physics objects, energy scale and resolution of electrons and muons, c-tagging and mistagging rates, pileup, and luminosity. A profile likelihood fit of the background expectation to the data is performed simultaneously in all CRs [49], and from it the background normalizations are extracted. The nor­ malization factors, which are consistent with unity within uncertainties, are then applied to the MC expectation in the signal regions. The first control region is populated largely by ft and W + jets. It contains events with exactly one isolated electron or muon with pT above 50 GeV. The leading two jets, with pT > 130 and 50 GeV respectively, must be c-tagged. To select events containing W -> fv , the trans­ verse mass of the (f, E j'ss) system is required to be between 40 and 100 GeV. The upper bound reduces possible signal contamination from SUSY models that produce leptons in cascade decays. Finally, it is required that E j lss > 100 GeV and mCT > 150 GeV. The second control region is populated by Z -> f +f~ events with two opposite-sign, same-flavor leptons, where the minimum pT requirement is 70 GeV for the leading lepton and 7(6) GeV for the subleading electron (muon). The trans­ verse momenta of the leptons are added vectorially to the E j lss to mimic the Z -» vv decay, and the modulus of the resulting two-vector is required to be larger than 100 GeV. The leading two jets are required to be c-tagged and their pT must each be above 50 GeV. The invariant mass of

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the two leptons is required to be between 75 and 105 GeV (Z-mass interval). A third control region, populated almost exclusively by dileptonic ft events, contains events with two opposite-sign, different-flavor leptons, where the leading lepton has pT > 25 GeV and the subleading lepton Pi is above 7(6) GeV for electrons (muons). It is required that E j'ss > 50 GeV and > 50 GeV. The leading two jets are required to be c-tagged and have pT > 50 GeV. In all CRs, events with additional lepton candidates beyond the required number of signal leptons are vetoed using the same lepton requirements used to veto events in the SRs. The subdominant background contributions from dibosons, Ztt and Wft are estimated by MC simulation. Finally, the residual multijet background is estimated using a data-driven technique based on the smearing of jets in a low-£^“ss data sample with jet response func­ tions [50], The experimental and theoretical uncertainties affecting the main backgrounds are correlated between control and signal regions, and the data observed in control regions constrain the uncertainties on the expected yields in the signal regions. The residual uncertainty due to the theo­ retical modeling of the top-production background is about 7%. It is evaluated using additional MC samples generated with A c e r M C (where initial- and final-state radiation parameters are varied) an alternative fragmentation model ( h e r w ig ), an alternative generator ( m c @ n l o ), and by using diagram subtraction rather than diagram removal to account for the interference between ft and single top W /-channel production [51]. After the fit, the residual uncertainties on the W + jets and Z + je ts theoretical modeling account for less than 20% of the total uncertainty. The dominant contributions to the residual uncertainty on the total background are from c-tagging (—20%), normali­ zation uncertainties related to the numbers of events in the CRs (10%-20%), and JES (-10%). For the SUSY signal processes, theoretical uncertainties on the cross section due to the choice of renormalization and factorization scales and from PDFs are found to be between 14% and 16% for c masses between 100 and 550 GeV. Prior to the fit, the detector-related uncertainties with largest impact on the signal event yields are those for c-tagging (typically 15%-30%) and JES (typically 10%—30%). Table I reports the observed number of events and the SM predictions for each SR. The data are found to be below the SM background expectations, but consistent with them given the uncertainties. Figure 1 shows the measured mCT and mcc distributions in the mCT > 150 GeV region compared to the SM predictions. Monte Carlo estimates are shown after the normalizations extracted from the profile likelihood fit are applied. For illustrative purposes, the distributions expected for the simplified model with (c ,j°) masses of (400, 200) GeV and (550, 50) GeV are also shown.

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TABLE I. Expected and observed number of events for an integrated luminosity of 20.3 fb-1 at a/ s = 8 TeV. Top, Z + jets and W + jets contributions are estimated using the fit described in the text. For comparison, the numbers obtained using MC simulations only are shown in parentheses. The row labeled “Others” reports subdominant electroweak backgrounds estimated from MC simulations. The total uncertainties are also reported. mCT (GeV) Top Z + jets W + jets Multijets Others

Total Data

>150

>200

>250

7.4 ± 2 .7 (7.1) 14 ± 3 (13) 7.2 ± 4 .5 (7.4) 0.3 ± 0 .3 0.5 ± 0 .3

3.9 ± 1.6 (3.7) 7.7 ± 1.7 (7.0) 4.1 ± 2 .6 (4.2) 0.2 ± 0.2 0.4 ± 0 .3

1.6 ± 0 .7 (1.5) 4.3 ± 1.2 (3.9) 1.9 ± 1.2 (1.9) 0.05 ± 0.05 0.4 ± 0 .3

30±6 19

16±3 11

8.2±1.9 4

Since no significant excesses are observed, the results are translated into 95% confidence-level (C.L.) upper limits on contributions from non-SM processes using the CLS prescription [52]. Figure 2 shows the observed and expected exclusion limits at 95% C.L. on the c-jff mass plane, assuming a single accessible c particle with

m cc

BR(c -*■ c +x°l ) = 100%. The SR with the best expected sensitivity at each point in the plot is adopted as the nominal result. In the region where the c-tagged analysis of the ATLAS ~t -> c + search [18] provides a stronger expected limit, i.e., for m-c - m~n < m w, that result is used. The region excluded by the ATLAS monojet search described in Ref. [18] is shown separately as a grey shaded area. Systematic uncertainties, other than in the c pairproduction cross section, are treated as nuisance parameters and correlated when appropriate. For the SUSY scenario considered, the upper limit at 95% C.L. on the scalar-charm mass obtained in the most conservative cross-section hypothesis is 540 GeV for m~x o = 0 (increasing to 555 GeV for the central estimate of the signal cross section). Neutralino masses up to 200 GeV are similarly

[GeV]

FIG. 1 (color online). Distributions of mCT (top) and mcc (bottom), and their corresponding SM predictions. Signal region selections (mCT > 150 GeV for the mcc distribution) are applied, other than for the variable plotted. Arrows indicate the SR requirements on mCT and mcc. In the ratio plots, the grey bands correspond to the combined MC statistical and experimental systematic uncertainty.

FIG. 2 (color online). Exclusion limits at 95% C.L. in the c-%? mass plane. The observed (solid red line) and expected (dashed blue line) limits include all uncertainties except for the theoretical signal cross-section uncertainty (PDF and scale). The band around the expected limits show ±lcr uncertainties. The dotted lines around the observed limits represent the results obtained when moving the nominal signal cross section up or down by the ±ler theoretical uncertainty.

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excluded for m-c < 490 GeV. This significantly extends the results of previous flavor-blind analyses [16,17], which provide no exclusion for m^o > 160 GeV, nor for single light squarks with masses above 440 GeV. The signal regions are used to set limits on the effective cross sections being the azimuthal angle around the beam pipe. The pseudorapidity is defined in terms of the polar angle 6 as rj = -ln tan (0 /2 ), while AR = [(A^)2 + (A0)2] '/2. [26] ATLAS Collaboration, Jet energy measurement with the ATLAS detector in proton-proton collisions at y/s = 7 TeV, Eur. Phys. J. C 73, 2304 (2013). [27] M. Cacciari and G. P. Salam, Pileup subtraction using jet areas, Phys. Lett. B 659, 119 (2008). [28] ATLAS Collaboration, Electron reconstruction and identi­ fication efficiency measurements with the ATLAS detector using the 2011 LHC proton-proton collision data, Eur. Phys. J. C 74, 2941 (2014). [29] ATLAS Collaboration, Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data, Eur. Phys. J. C 74, 3130 (2014). [30] ATLAS Collaboration. Electron performance measurements with the ATLAS detector using the 2010 LHC protonproton collision data, Eur. Phys. J. C 72, 1909 (2012). [31] ATLAS Collaboration, Search for new phenomena in final states with large jet multiplicities and missing transverse momentum at v^s = 8 TeV proton-proton collisions using the ATLAS experiment, J. High Energy Phys. 10 (2013) 130. [32] ATLAS Collaboration, Performance of missing transverse momentum reconstruction in proton-proton collisions at y/s = 7 TeV with ATLAS, Eur. Phys. J. C 72, 1844 (2012). [33] ATLAS Collaboration, Performance and Calibration of the JetFitterCharm Algorithm for c-Jet Identification, ATL-PHYS-PUB-2015-001, 2015 [https://atlas.web.cern .ch/Atlas/GROUPS/PHYSICS/PUBNOTES/ATL-PHYSPUB-2015-001/]. [34] ATLAS Collaboration, Calibration of fo-tagging using dileptonic top pair events in a combinatorial likelihood appoach with the ATLAS experiment, ATLAS-CONF2014-004, 2014 [http://cds.cem.ch/record/1664335]. [35] ATLAS Collaboration, Calibration of the performance of btagging for c and light-flavour jets in the 2012 ATLAS data, ATLAS-CONF-2014-046, 2014 [http://cds.cem.ch/record/ 1741020], [36] G. Polesello and D. Tovey, Supersymmetric particle mass measurement with the boost- corrected contransverse mass, J. High Energy Phys. 03 (2010) 030.

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Argyropoulos 42 M. Arik,I9a A. J. Armbruster,30 O. Amaez,30 V. Amal,82 H. Arnold,48 M. Arratia,"8 O. Arslan,21 A. Artamonov,97 G. Artoni,23 S. Asai,156 N. Asbah,42 A. Ashkenazi,154 B. Asman,147a’147b L. Asquith,150 K. Assamagan,25 R. Astalos,145,1 M. Atkinson,166 N. B. Atlay,142 B. Auerbach,6 K. Augsten,128 M. Aurousseau,146b G. Avolio,30 B. Axen,15 M. K. Ayoub,117 G. Azuelos,95,6 M. A. Baak,30 A. E. Baas,583 C. Bacci,1353,1356 H. Bachacou,137 K. Bachas,155 M. Backes,30 M. Backhaus,30 P. Bagiacchi,133a,133b P. Bagnaia,1333’1336 Y. Bai,33a T. Bain,35 J.T. Baines,131 O. K. Baker,177 P. Balek,129 T. Balestri,149 F. Balli,84 E. Banas,39 Sw. Banerjee,174 A. A. E. Bannoura,176 H. S. Bansil,18 L. Barak,173 S. P. Baranov,96 E. L. Barberio,88 D. Barberis,503,506 M. Barbero,85 T. Barillari,101 M. Barisonzi,1653,1656 T. Barklow,144 N. Barlow,28 S. L. Barnes,84 B .M . Barnett,131 R. M. Barnett,15 Z. Barnovska,5 A. Baroncelli,1353 G. Barone,49 A. J. Barr,120 F. Barreiro,8" J. Barreiro Guimaraes da Costa,37 R. Bartoldus,144 A. E. Barton,72 P. Bartos,1453 A. Bassalat,117 A. Basye,166 R. L. Bates,53 S.J. Batista,159 J. R. Batley,28 M. Battaglia,138 M. Bauce,1333,1336 F. Bauer,137 H. S. Bawa,144,1 J. B. Beacham,111 M .D . Beattie,72 T. Beau,80 P. H. Beauchemin,16" R. Beccherle,1243,1246 P. Bechtle,21 H. P. Beck,17,g K. Becker,120 S. Becker,100 M. Beckingham,171 C. Becot,117 A. J. Beddall,19c A. Beddall,19c V. A. Bednyakov,65 C. P. Bee,149 L. J. Beemster,107 T. A. Beermann,176 M. Begel,25 K. Behr,120 C. Belanger-Champagne,87 P. J. Bell,49 W. H. Bell,49 G. Bella,154 L. Bellagamba,203 A. Bellerive,29 M. Bellomo,86 K. Belotskiy,98 O. Beltramello,30 O. Benary,154 D. Benchekroun,1363 M. Bender,100 K. Bendtz,1473,1476 N. Benekos,10 Y. Benhammou,154 E. Benhar Noccioli,49 J. A. Benitez Garcia,1606 D. P. Benjamin,45 J. R. Bensinger,23 S. Bentvelsen,107 L. Beresford,120 M. Beretta,47 D. Berge,107 E. Bergeaas Kuutmann,167 N. Berger,5 F. Berghaus,170 J. Beringer,15 C. Bernard,22 N. R. Bernard,86 C. Bem ius,110 F.U. Bemlochner,21 T. Berry,77 P. Berta,1"9 C. Bertella,83 G. Bertoli,1473,1476 F. Bertolucci,1243,1246 C. Bertsche,113 D. Bertsche,113 M. I. Besana,9’3 G. J. Besjes,106 O. Bessidskaia Bylund,1473,1476 M. Bessner,42 N. Besson,137 C. Betancourt,48 S. Bethke,101 A. J. Bevan,76 W. Bhimji,46 R. M. Bianchi,125 L. Bianchini,23 M. Bianco,30 O. Biebel,100 S.P. Bieniek,78 M. Biglietti,1353 J. Bilbao De Mendizabal,49 H. Bilokon,47 M. Bindi,54 S. Binet,117 A. Bingul,19c C. Bini,133a,133b C.W . Black,151 J. E. Black,144 K. M. Black,22 D. Blackburn,139 R. E. Blair,6 J.-B. Blanchard,137 J.E . Blanco,77 T. Blazek,1453 I. Bloch,42 C. Blocker,23 W. Blum,83,3 U. Blumenschein,54 G. J. Bobbink,107 V. S. Bobrovnikov,109'0 S. S. Bocchetta,81 A. Bocci,45 C. Bock,100 C. R. Boddy,1"0 M. Boehler,48 J. A. Bogaerts,30 A. G. Bogdanchikov,109 C. Bohrn,1473 V. Boisvert,77 T. Bold,383 V. Boldea,263 A. S. Boldyrev,99 M. Bomben,80 M. Bona,76 M. Boonekamp,137 A. Borisov,130 G. Borissov,72 S. Borroni,42 J. Bortfeldt,100 V. Bortolotto,603 K. Bos,107 D. Boscherini,203 M. Bosman,12 J. Boudreau,1"5 J. Bouffard,2 E. V. Bouhova-Thacker,7" D. Boumediene,34 C. Bourdarios,117 N. Bousson,114 S. Boutouil,1360 A. Boveia,30 J. Boyd,41 I. R. Boyko,65 I. Bozic,13 j. Bracinik,18 A. Brandt,8 G. Brandt,16 O. Brandt,583 U. Bratzler,157 B. Brau,86 J.E . Brau,116 H. M. Braun,176,3 S.F. Brazzale,165a,165c K. Brendlinger,122 A. J. Brennan,88 L. Brenner,107 R. Brenner,167 S. Bressler,173 K. Bristow,146c T. M. Bristow,46 D. Britton,53 F. M. Brochu,28 I. Brock,"1 R. Brock,90 J. Bronner,101 G. Brooijmans,35 T. Brooks,77 W. K. Brooks,326 J. Brosamer,15 E. Brost,116 J. Brown,66 P. A. Bruckman de Renstrom,'9 D. Bruncko,1456 R. Bruneliere 48 A. Bruni,203 G. Bruni,203 M. Bruschi,203 L. Bryngemark,81 T. Buanes,14 Q. Buat,143 F. Bucci,49 P. Buchholz,142 A. G. Buckley,53 S. I. Buda,263 1. A. Budagov,65 F. Buehrer,48 L. Bugge,119 M. K. Bugge,119 O. Bulekov,98 H. Burckhart,30 S. Burdin,74 B. Burghgrave,108 S. Burke,131 I. Burmeister,43 E. Busato,34 D. Biischer,48 V. Buscher,83 P. Bussey,53 C. P. Buszello,167 J. M. Butler,22 A. I. Butt,3 C. M. Buttar,53 J. M. Butterworth,78 P. Butti,107 W. Buttinger,25 A. Buzatu,53 S. Cabrera Urban,168 D. Caforio,128 O. Cakir,43 P. Calafiura,15 A. Calandri,137 G. Calderini,80 P. Calfayan,100 L. P. Caloba,243 D. Calvet,34 S. Calvet,34 R. Camacho Toro,49 S. Camarda,42 D. Cameron,119 L. M. Caminada,16 R. Caminal Armadans,12 S. Campana,30 M. Campanelli,78 A. Campoverde,149 V. Canale,1043,1046 A. Canepa,1603 M. Cano Bret,76 J. Cantero,8" R. Cantrill,1263 T. Cao,40 M. D. M. Capeans Garrido,30 I. Caprini,26,1 M. Caprini,26,1 M. Capua,373"376 R. Caputo,83 R. Cardarelli,1343 T. Carli,30 G. Carlino,1043 L. Carminati,913,916 S. Caron,106 E. Carquin,323 G. D. Carrillo-Montoya,146c 161801-7

PRL 114,16 1 8 0 1 (2015) J.

PHYSICAL

REVIEW

LETTERS

week ending 24 APRIL 2015

R. Carter,28 J. C arvalho,126a,126c d . Casadei,78 M. P. C asado,12 M. C asolino,12 E. Castaneda-M iranda.l46b A. C astelli,107

V. Castillo G im enez,168 N. F. C astro,i26a P. C atastini,77 A. Catinaccio,30 J. R. C atm ore,119 A. Cattai,30 G. C attani,I34a'134b J. C audron,83 V. C avaliere,166 D. Cavalli,9la M. C avalli-Sforza,12 V. C avasinni,124al24b F. C eradini,135a'135b B .C . Cerio,45 K. Cerny,129 A. S. Cerqueira,24b A. C erri,150 L. Cerrito,76 F. C erutti,15 M. Cerv,30 A. C ervelli,17 S. A. C etin,l9b A. C hafaq,1363 D. C hakraborty,108 I. C halupkova,129 P. C hang,166 B. Chapleau,87 J. D. C hapm an,28 D. C harfeddine,117 D. G. C harlton,18 C.

C. C h au ,159 C. A. Chavez B arajas,150 S. C heatham ,153 A. Chegwidden,90 S. Chekanov,6 S. V. Chekulaev,1603

G. A. Chelkov,65,b M. A. Chelstow ska,89 C. Chen,64 H. Chen,25 K. C hen,149 L. Chen,3341 S. Chen,33c X. Chen,33f Y. Chen,67 H. C. C heng,89 Y. C heng,31 A. Cheplakov,65 E. C herem ushkina,130 R. Cherkaoui El M oursli,136"’ V. C hem yatin,25’3 E. Cheu,7 L. C hevalier,137 V. Chiarella,47 J. T. C hilders,6 A. Chilingarov,72 G. Chiodini,73a A. S. C hisholm ,18 R .T. Chislett,78 A. Chitan,26a M. V. Chizhov,67 S. C houridou,9 B. K. B. C how ,100 D. Chrom ek-Burckhart,30 M. L. C h u ,152 J. C hudoba,127 J. J. Chw astow ski,39 L. C hytka,115 G. C iapetti,133a’133b A. K. Ciftci,4a D. Cinca,53 V. Cindro,75 A. C iocio,15 Z. H. C itron,173 M. Citterio,91a M. C iubancan,26a A. Clark,49 P. J. Clark,46 R. N. C larke,15 W. C leland,125 C. Clement, 147a'147b Y. Coadou,85 M. C obal,165a'165c A. C occaro,139 J. Cochran,64 L. Coffey,23 J. G. C ogan,144 B. Cole,35 S. C ole,108 A. P. C olijn,107 J. Collot,55 T. C olom bo,78" G. C om postella,101 P. Conde M uino,126a l26b E. Coniavitis,48 S .H . C onnell,146b I. A. Connelly,77 S. M. C onsonni,91a’91b V. Consorti,48 S. Constantinescu,263 C. C onta,12Ia'121b G. Conti,30 F. C onventi,104a’j M. C ooke,15 B. D. Cooper.78 A. M. Cooper-Sarkar,120 K. C opic,15 T. C om elissen,176 M. Corradi,20a F. Corriveau,87 k A. C orso-R adu,164 A. Cortes-G onzalez,12 G. C ortiana,101 M .J. C osta,168 D. C ostanzo,140 D. Cote,8 G. Cottin,28 G. Cowan,77 B .E . Cox,84 K.

C ranm er,110 G. Cree,29 S. Crepe-Renaudin,55 F. Crescioli,80 W. A. C ribbs,147a,147b M. Crispin O rtuzar,120

M. Cristinziani,"1V. C roft,106 G. Crosetti,37a’37b T. C uhadarD onszelm ann,140 J. C um m ings,177 M. Curatolo,47 C. C uthbert,151 H. C zirr,142 P. C zodrow ski,’ S. D ’A uria,53 M. D 'O nofrio,74 M .J. Da Cunha Sargedas De Sousa,l26a,l26b C. Da Via,84 W. D abrow ski,383 A. D afinca,120 T. Dai,89 O. D ale,14 F. Dallaire,95 C. D allapiccola,86 M. Dam,36 J. R. Dandoy,31 A. C. D aniells,18 M. D anninger,169 M. Dano H offm ann,1'7 V. Dao,48 G. Darbo,50a S. D arm ora,8 J. D assoulas,3 A. D attagupta,61 W. Davey.21 C. D avid,170 T. D avidek,129 E. D avies,120'1 M. D avies,154 O. D avignon,80 P. Davison,78 Y. Davygora,583 E. D aw e,1431. D aw son,140 R. K. D aya-Ishm ukham etova,86 K. De,8 R. de A sm undis,1043 S. De Castro,20a,20b S. De C ecco,80 N. De G root,106 P. de Jong,107 H. De la Torre,82 F. D e Lorenzi,64 L. De N ooij,107 D. De Pedis,I33a A. De Salvo,133a U. De Sanctis,150 A. De S anto,150 J. B. De Vivie De R egie,117 W. J. Deam aley,72 R. D ebbe,27 C.

D ebenedetti,138 D. V. D edovich,65 I. D eigaard,107 J. Del Peso,82 T. Del Prete,124a’124b D. D elgove,117 F. D eliot,137

C. M. Delitzsch,49 M. Deliyergiyev,77 A. D ell’A cqua,30 L. D ell’A sta,22 M. D ell’O rso,124a’124b M. Della Pietra,104a,j D. della Volpe,49 M. Delm astro,5 P A . D elsart,55 C. D eluca,107 D. A. D eM arco,159 S. D em ers,177 M. Demichev,65 A. Demilly,80 S. P. D enisov,130 D. D erendarz,39 J .E . D erkaoui,136d F. D erue,80 P. Dervan,74 K. D esch,21 C. Deterre,42 P. O. Deviveiros,30 A. D ew hurst,131 S. D haliw al,107 A. Di C iaccio,134a,134b L. Di Ciaccio,5 A. Di D om enico,133a,133b C. Di D onato,104a l04h A. Di G irolam o,30 B. Di G irolam o,30 A. Di M attia,15' B. Di M icco,135a l35b R. Di N ardo,47 A. Di Sim one,48 R. Di Sipio,20a 20b D. Di Valentino,29 C. D iaconu,87 M. D iam ond,159 F. A. Dias 46 M. A. Diaz,32a E.

B. D iehl,81 J. D ietrich,16 T. A. D ietzsch,583 S. D iglio,85 A. D im itrievska,13 J. Dingfelder,21 F. D ittus,30 F. D jam a,85

T. D jobava,516 J. I. D juvsland,583 M. A. B. do Vale,24c D. D obos,30 M. Dobre,26a C. Doglioni,49 T. Doherty,53 T. D ohm ae,156 J. D olejsi,129 Z. D olezal,129 B. A. D olgoshein,98'3 M. Donadelli,240 S. D onati,i:24a’1:246 P. D ondero,121a’121b J. D onini,34 J. D opke,131 A. D oria,1043 M. T. D ova,71 A. T. Doyle,53 M. D ris,10 E. D ubreuil,34 E. D uchovni,173 G. D uckeck,100 O. A. D ucu,“6a D. D uda,176 A. Dudarev,30 L. D uflot,117 L. D uguid,77 M. Diihrssen,30 M. D unford,583 H. Duran Yildiz,43 M. D uren,52 A. D urglishvili,516 D. Duschinger,44 M. D w uznik,383 M. D yndal,383 W. Edson,2 N. C. Edwards,46 W. E h re n fe ld r1 T. Eifert,30 G. E igen,14 K. Einsw eiler,15 T. E kelof,167 M. El K acim i,136c M. E llert,167 S. Elies,5 F.

Ellinghaus,83 A. A. E lliot,170 N. Ellis,30 J. Elm sheuser,100 M. Elsing,30 D. Em eliyanov,131 Y. E nari,156 O. C. Endner,83

M. Endo,118 R. E ngelm ann,149 J. Erdm ann,43 A. Ereditato,17 D. Eriksson,1473 G. E rnis,176 J. Ernst,2 M. Ernst,25 S. E rrede,166 E. Ertel,83 M. Escalier,117 H. Esch,43 C. E scobar,127 B. Esposito,47 A. I. Etienvre,137 E. E tzion,154 H. Evans,61 A. Ezhilov,123 L. Fabbri,203’206 G. Facini,31 R. M. Fakhrutdinov,130 S. Falciano,1333 R. J. Falla,78 J. Faltova,129 Y. Fang,333 M. Fanti,91a'91b A. Farbin,8 A. Farilla,135'1 T. F arooque,1- S. Farrell,17 S .M . Farrington,171 P. Farthouat,30 F. F assi,136e P. Fassnacht,30 D. Fassouliotis,9 A. Favareto,50a’50b L. Fayard,117 P. Federic,1453 O. L. F edin,123’m W. Fedorko,169 S. Feigl,30 L. Feligioni,85 C. Feng,33d E. J. Feng,6 H. Feng,89 A. B. F enyuk,130 P. Fernandez M artinez,168 S. Fernandez Perez,30 S. Ferrag,53 J. Ferrando,53 A. F errari,167 P. Ferrari,107 R. Ferrari,1213 D. E. Ferreira de Lim a,53 A. Ferrer,168 D. Ferrere,49 C. Ferretti,89 A. Ferretto Parodi,50a50b M. Fiascaris,31 F. Fiedler,83 A. Filipcic,75 M. Filipuzzi,42 F. Filthaut,106 M. Fincke-K eeler,170

161801-8

PRL 114 , 161801 (2015)

PHYSICAL

REVIEW

LETTERS

week ending 24 APRIL 2015

K. D. Finelli,151 M. C. N. Fiolhais,126a’126c L. Fiorini,168 A. Firan,40 A. Fischer,2 C. Fischer,12 J. Fischer,176 W. C. Fisher,90 E. A. Fitzgerald,23 M. Flechl,481. Fleck,14- P. Fleischm ann,89 S. Fleischm ann,176 G. T. Fletcher,140 G. Fletcher,76 T. F lick,176 A. Floderus,81 L. R. Flores Castillo,603 M. J. Flowerdew,101 A. Form ica,1"’7 A. Forti,84 D. Fournier,11' H. Fox,72 S. Fracchia,12 P. Francavilla,80 M. Franchini,203’206 D. Francis,30 L. Franconi,119 M. Franklin,57 M. Fratem ali,12]a,121b D. Freeborn,78 S.T . French,28 F. Friedrich,44 D. Froidevaux,30 J. A. Frost,120 C. F ukunaga,157 E. Fullana Torregrosa,83 B .G . F ulsom ,144 J. Fuster,168 C. G abaldon,55 O. G abizon,176 A. Gabrielli,203’206 A. G abrielli,133a’133b S. G adatsch,107 S. Gadomski,49 G. Gagliardi,503’506 P. G agnon,61 C. G alea,106 B. G alhardo,126a'126c E. J. G allas,120 B. J. G allop,131 P. G allus,128 G. Galster,36 K. K. G an ,111 J. G ao,33b Y. S. G ao,1440' F. M. Garay Walls,46 F. G arberson,177 C. G arcia,168 J. E. Garcia N avarro,168 M. G arcia-Sciveres,15 R. W. Gardner,31 N. G arelli,144 V. G aronne,30 C. Gatti,47 G. G audio,1213 B. G aur,142 L. Gauthier,95 P. G auzzi,133a’133b I. L. Gavrilenko,96 C. G ay,169 G. Gaycken,21 E .N . G azis,10 P. Ge,33d Z. G eese,169 C. N. P. G ee,131 D. A. A. G eerts,107 Ch. G eich-G im bel,21 C. Gem rae,503 M. H. Genest,55 S. G entile,1333' 1” 1’ M. George,54 S. George,77 D. G erbaudo,164 A. G ershon,154 H. G hazlane,1366 N. G hodbane,’4 B. G iacobbe,203 S. G iagu,133a,133b V. G iangiobbe,12 P. G iannetti,1243’1246 F. G ianotti,30 B. G ibbard,25 S. M. G ibson,77 M. G ilchriese,15 T. P. S. Gillam ,28 D. Gillberg,30 G. Gilles,34 D .M . Gingrich,3’6 N. Giokaris,9 M .P. G iordani,165a’165c F. M. Giorgi,20a F. M. G iorgi,16 P.F. G iraud,137 D. Giugni,913 C. Giuliani,48 M. Giulini,586 B. K. G jelsten,119 S. G kaitatzis,155 I. G kialas,155 E. L. G kougkousis,117 L. K. G ladilin,99 C. G lasm an,82 J. Glatzer,30 P .C .F . Glaysher,46 A. Glazov,42 M. G oblirsch-K olb,101 J. R. Goddard,76 J. G odlew ski,39 S. Goldfarb,89 T. Golling,49 D. G olubkov,130 A. G om es,126a l26b l26d R. G onpalo,1263 J. Goncalves Pinto Firm ino Da C osta,137 L. Gonella,21 S. G onzalez de la H oz,168 G. G onzalez Parra,12 S. Gonzalez-Sevilla,49 L. G oossens,30 P. A. Gorbounov,97 H. A. G ordon,25 I. Gorelov,105 B. G orini,30 E. G orini,73a’73b A. Gorisek,75 E. G om icki,39 A. T. Goshaw,45 C. Gossling,43 M. I. G ostkin,65 M. G ouighri,1363 D. G oujdam i,136c A. G. G oussiou,139 H. M. X. G rabas,138 L. Graber,54 I. G rabow ska-Bold,383 P. Grafstr6m ,20a20b K-J. Grahn,42 J. Gram ling,49 E. G ram stad,119 S. G rancagnolo,16 V. G rassi,149 V. G ratchev,12’ H. M. Gray,30 E. G raziani,1353 Z. D. G reenw ood.79’" K. Gregersen,78 I. M. Gregor,4- P. G renier,144 J. Griffiths,8 A. A. G rillo,138 K. G rim m ,72 S. G rinstein,12’0 Ph. Gris,34 Y. V. G rishkevich," J.-F. G rivaz,117 J. P. G rohs,44 A. Grohsjean,42 E. G ross,173 J. Grosse-Knetter,54 G. C. G rossi,13431’4b Z. J. G rout,150 L. Guan,3lb J. G uenther.1-8 F. Guescini,49 D. G uest,177 O. G ueta,154 E. G uido,50a’50b T. G uillem in,117 S. G uindon,2 U. G ul,53 C. G um pert,44 J. G uo,33e S. G upta,120 P. G utierrez,113 N. G. Gutierrez Ortiz,53 C. Gutschow,44 N. G uttm an,154 C. G uyot,1'7 C. G w enlan,1-0 C .B . G w illiam ,74 A. H aas,110 C. H aber,15 H. K. Hadavand,8 N. H addad,1366 P. Haefner,21 S. Hagebock,21 Z. H ajduk,39 H. H akobyan,178 M. Haleem ,42 J. Haley,114 D. H all,120 G. Halladjian,90 G. D. Hallewell,85 K. H am acher,176 P. H am al,115 K. H am ano,170 M. Hamer,54 A. H am ilton,1463 S. H am ilton,162 G. N. H am ity,1460 P. G. Hamnett,4- L. H an,33b K. H anagaki,118 K. H anaw a,156 M. H ance,15 P. Hanke,583 R. H anna,137 J.B . Hansen,36 J. D. Hansen,36 P. H. H ansen,36 K. H ara,161 A. S. H ard,174 T. H arenberg,176 F. H ariri,117 S. Harkusha,92 R. D. Harrington,46 P.F. H arrison,171 F. H artjes,107 M. H asegawa,67 S. H asegaw a,103 Y. H asegaw a,141 A. H asib,113 S. H assani,137 S. H aug,17 R. Hauser,90 L. H ausw ald,44 M. H avranek,127 C. M. H aw kes,18 R. J. Haw kings,30 A. D. H aw kins,81 T. H ayashi,161 D. H ayden,90 C. P. H ays,120 J. M. Hays,76 H. S. H ayw ard,74 S. J. H ayw ood,131 S. J. H ead,18 T. H eck,83 V. Hedberg,81 L. H eelan,8 S. H eim ,122 T. H eim ,176 B. H einem ann,15 L. H einrich,110 J. H ejbal,127 L. Helary,-- M. Heller,30 S. H eilm an,147a,147b D. H ellm ich,-1 C. H elsens,30 J. H enderson,120 R. C. W. H enderson,72 Y. H eng,174 C. Hengler,42 A. H enrichs,177 A. M. Henriques Correia,30 S. Henrot-Versille,117 G. H. H erbert,16 Y. H ernandez Jim enez,168 R. H errberg-Schubert,16 G. Herten,48 R. Hertenberger,100 L. Hervas,30 G. G. H esketh.78 N. P. H essey,107 R. H ickling,76 E. H igon-R odriguez,168 E. H ill,170 J. C. Hill,28 K. H. Hiller,4S . J. H illier,18 I. H inchliffe,15 E. H ines,122 R. R. H inm an,15 M. H irose,158 D. H irschbuehl,176 J. H obbs,149 N. H od,107 M. C. H odgkinson,140 P. H odgson,140 A. H oecker,30 M. R. H oeferkam p,105 F. H oenig,100 M. H ohlfeld,83 T. R. H olm es,15 T. M. H ong,122 L. H ooft van H uysduynen,110 W. H. H opkins,116 Y. H orii,103 A. J. H orton,143 J-Y. Hostachy,55 S. H ou,15A. H oum m ada,1363 J. H ow ard,120 J. Howarth,42 M. H rabovsky,1151. H ristova,16 J. H rivnac,117 T. H ryn’ova,5 A. Hrynevich,93 C. H su,1466 P. J. H su,152’p S.-C. H su , 139 D. H u ,35 Q. Hu,33b X. H u,89 Y. H uang,42 Z. Hubacek,30 F. H ubaut,85 F. H uegging,21 T. B. H uffm an,120 E. W. H ughes,35 G. H ughes,72 M. Huhtinen,30 T. A. Hiilsing,83 N. Huseynov,65’6 J. H uston,90 J. Huth,57 G.

Iacobucci,49 G. Iakovidis,25 I. Ibragim ov,14- L. Iconom idou-Fayard,117 E. Ideal,177 Z. Idrissi,136e P. Iengo,104a

O. Igonkina,107 T. Iizaw a,172 Y. Ikegam i,66 K. Ikem atsu,142 M. Ikeno,66 Y. Ilchenko,3l q D. Iliadis,155 N. Ilic,159 Y. Inam aru,67 T. Ince,101 P. Ioannou,9 M. Iodice,1353 K. Iordanidou,9 V. Ippolito,”7 A. Irles Q uiles,168 C. Isaksson,167 M. Ishino,68 M. Ishitsuka,158 R. Ishm ukham etov,111 C. Issever,120 S. Istin,193 J. M. Iturbe Ponce,84 R. Iuppa,134a l34b J. Ivarsson,81 W. Iw anski,39 H. Iw asaki,66 J.M . Izen,41 V. Izzo,104a B. Jackson,122 M. Jackson,74 P. Jackson,1 M .R . Jaekel,30 V. Jain,2

161801-9

PHYSICAL

PRL 114, 161801 (2015)

REVIEW

week ending 24 APRIL 2015

LETTERS

K. Jakobs,48 S. Jakobsen,30 T. Jakoubek,127 J. Jakubek,128 D. O. Jam in,152 D. K. Jana.79 E. Jansen,78 R. W. Jansky,62 J. Janssen,21 M. Jan u s,171 G. Jarlskog,81 N. Javadov,65-0 T. Javurek,48 L. Jeanty,15 J. Jejelava,51a,r G.-Y. Jeng,151 D. Jennens,8 • 48,s P. Jenni, J. Jentzsch,43 C. Jeske,171 S. Jezequel,5 H. J i,174 J. Jia ,149 Y. J ia n g ,'1'1 J. Jim enez Pena, 168 S. Jin,33a A. Jinaru,26a O. Jinnouchi,158 M. D. Joergensen,36 P. Johansson,140 K. A. Johns,7 K. Jon-A nd,1473-1476 G. Jones,171 R. W. L. Jones,72 T. J. Jones,74 J. Jongm anns,58a P. M. Jorge,1263-1266 K. D. Joshi,84 J. Jovicevic,148 X. Ju ,174 C. A. Jung,43 P. Jussel,62 A. Juste R ozas,12 " M. K aci,168 A. K aczm arska,39 M. K ado,117 H. K agan,111 M. K agan,144 S. J. K ahn,85 E. Kajomovitz,45 C. W. K alderon,120 S. Kama,40 A. K am enshchikov,130 N. K anaya,156 M. K aneda,30 S. Kaneti,28 V. A. Kantserov,98 .53 10 J. Kanzaki,66 B. K aplan,110 A. Kapliy,31 D. Kar,53 K. K arakostas,10 A. Karam aoun,3 N. K arastathis,10'107 M. J. Kareem,54 M. K am evskiy,83 S .N . Karpov,65 Z. M. Karpova,65 K. K arthik,110 V. Kartvelishvili,72 A. N. K aryukhin,130 L. K ashif,174 R. D. K ass,111 A. K astanas,14 Y. K ataoka,156 A. Katre,49 J. Katzy,42 K. Kawagoe,70 T. K aw am oto,156 G. K awam ura,54 109 170 . 65 S. K azam a,156 V. F. K azanin,luy M. Y. Kazarinov,05 R. K eeler,1'0 R. Kehoe,40 M. Keil,54 J. S. Keller,42 J. J. Kempster,.77 H. K eoshkerian,84 O. K epka,127 B .P. Kersevan,75 S. K ersten,176 R. A. Keyes,87 F. Khalil-zada,11 H. K handanyan,147a,147b A. K hanov,114 A. K harlam ov,109 A. Khodinov,98 A. K hom ich,5811 T. J. K hoo,28 G. Khoriauli,21 V. Khovanskiy,97 E. Khramov,65 J. Khubua,516-1 H. Y. K im ,8 H. K im ,1473-1476 S. H. K im ,161 N. Kirnura,155 O. K ind,16 B. T. King,74 M. K ing,168 R. S . B. K ing,120 S .B . K ing,169 J. K irk,131 A. E. K iryunin,101 T. Kishim oto,67 D. Kisielewska,38a F. Kiss,48 K. K iuchi,161 145b 74 74 E. Kladiva, M. H. K lein,35 M. Klein,74 U. Klein,74 K. Kleinknecht,8-1 P. K lim ek,1473-1476 A. Klimentov,25 .84 ,

30 ,

106 ,

58a ,

107 ,

101 R. K lingenberg,43 J. A. Klinger,54 T. K lioutchnikova,"' P. F. K lok,'°° E.-E. Kluge,553 P. K luit,'"' S. K luth,lul E. Kneringer, 62

E. B .F. G. K noops,85 A. K nue,53 D. K obayashi,158 T. K obayashi,156 M. Kobe!,44 M. K ocian,144 P. K odys,129 T. Koffas,29 E. K offem an,107 L. A. K ogan,120 S. K ohlm ann,176 Z. K ohout,128 T. Kohriki,66 T. K oi,144 H. K olanoski,16 I. Koletsou,5 A. A. Komar,96-3 Y. K om ori,156 T. Kondo,66 N. K ondrashova,42 K. Koneke,48 A. C. K onig,106 S. K onig,83 T. Kono,66-u R. K onoplich,110-' N. Konstantinidis,78 R. K opeliansky,15-1 S. Kopemy,38a L. K opke,83 A. K. Kopp,48 K. Korcyl,39 K. K ordas,155 A. K orn,78 A. A. K orol,109-0 I. K orolkov,1- E. V. K orolkova,140 O. Kortner,101 S. Kortner,101 T. K osek,129 ,65

45

V. V. K ostyukhin,-1 V. M. Kotov,03 A. Kotwal,43 A. K ourkoum eli-Charalam pidi,133 C. Kourkoumelis,9 V. Kouskoura, 25 A. K outsm an,1603 R. K ow alew ski,170 T .Z . Kowalski,383 W. K ozanecki,137 A. S. K ozhin,130 V. A. Kram arenko,99 G. Kram berger,73 D. Krasnopevtsev,98 M. W. Krasny,80 A. Krasznahorkay,30 J. K. Kraus,21 A. K ravchenko,25 S. K reiss,110 M. Kretz,58" J. Kretzschm ar,74 K. K reutzfeldt,52 P. K rieger,159 K. K rizka,31 K. Kroeninger,43 H. K roha,101 J. K roll,122 J. K roseberg,21 J. K rstic,13 U. K ruchonak,65 H. Kruger,21 N. Krum nack,64 Z. V. Krum shteyn,65 A. K ruse,174 M. C. Kruse,45 M. Kruskal,22 T. K ubota,88 H. Kucuk,78 S. Kuday,4c S. Kuehn,48 A. Kugel,58c F. K uger,175 A. K uhl,138 T. Kuhl,42 V. Kukhtin,63 Y. K ulchitsky,92 S. Kuleshov,326 M. K una,1333,1336 T. Kunigo,68 A. K upco,127 H. Kurashige,67 Y. A. K urochkin,92 R. K urum ida,67 V. K us,127 E. S. K uw ertz,148 M. K uze,158 J. K vita,115 T. K w an,170 D. K yriazopoulos,140 A. La Rosa,49 J. L. L a Rosa Navarro,240 L. La Rotonda,373-376 C. Lacasta,168 F. Lacava,1333’1336 J. Lacey,29 H. Lacker,16 D. Lacour,80 V. R. L acuesta,168 E. Ladygin,65 R. Lafaye,5 B. Laforge,80 T. L agouri,177 S. Lai,48 L. L am boum e,78 S. Lam m ers,61 C. L. Larnpen.7 W. Lam pl,7 E. Lanqon,137 U. Landgraf,48 M. P, J. Landon,76 V. S. Lang,583 A. J. L ankford,164 F. Lanni,25 K. Lantzsch,30 S. Laplace,80 C. Lapoire,30 J. F. Laporte,137 T. Lari,913 F. Lasagni M anghi,203’206 M. Lassnig,30 P. Laurelli,47 W. L avrijsen,13 A. T. L aw ,138 P. L aycock,74 O. Le D ortz,80 E. Le G uiniec,85 E. Le M enedeu,12 T. LeCom pte,6 F. Ledroit-G uillon,33 C. A. L ee,1466 S. C. L ee,13- L. L ee.1 G. Lefebvre,80 M. Lefebvre,170 F. Legger,100 C. L eggett,15 A. Lehan,74 G. Lehm ann M iotto,30 X. Lei,7 W. A. Leight,29 A. L eisos,155 A. G. L eister,177 M. A. L. Leite,24d R. Leitner,129 D. L ellouch,173 B. Lem m er,54 K. J. C. Leney,78 T. Lenz,21 G. L enzen,176 B. Lenzi,30 R. Leone,7 S. L eone,1243,1246 C. Leonidopoulos,46 S. L eontsinis,10 C. Leroy,95 C. G. Lester,28 M. Levchenko,123 J. Leveque,5 D. Levin,89 L .J. Levinson,173 M. L evy,18 A. L ew is,120 A. M. Leyko,21 M. Leyton,41 B. Li,33b,w B. Li,85 H. L i,149 H. L. Li,31 L. Li,45 L. Li,33e S. Li,45 Y. Li,33c,x Z. L iang,138 H. Liao,34 B. L iberti,1343 P. Lichard,30 K. L ie,166 J. Liebal,21 W. Liebig,14 C. Lim bach,-1 A. L im osani,1 1 S. C. L in ,15--y T. H. Lin,83 F. L inde,107 B. E. Lindquist,141 J. T. Linnem ann,90 E. L ipeles,122 A. Lipniacka,14 M. Lisovyi,42 T. M. L iss,166 D. Lissauer,25 A. Lister,169 A. M. Litke,138 B. Liu,152 D. Liu,152 J. Liu,85 J.B . Liu,33b K. Liu, 33b,z L. Liu.89 M. Liu,45 M. Liu,336 Y. Liu,336 M. L ivan.1-13-1 16 A. Lleres,55 J. Llorente M erino,82 76 , 42 S. L. L lo y d ,'0 F. Lo S terzo,15 E. Lobodzinska,4- P. L och,' W. S. Lockm an,138 F. K. Loebinger,84 A. E. Loevschall-Jensen, 36 A. Loginov,177 T. L o h se,16 K. Lohwasser,42 M. L okajicek,127 B. A. Long,22 J. D. Long,89 R. E. Long,72 K. A. L ooper,111 L. L opes,1-6a D. Lopez M ateos,57 B. Lopez Paredes,140 T — - Paz. n "~ 12 J. T Lorenz, T ------- 100 N. Lorenzo M artinez,61 M. L osada,163 I. T Lopez P. Loscutoff,15 P. J. L o sel,100 X. Lou,33a A. L ounis,117 J. Love,6 P. A. Love,72 F. L u,33a N. L u,89 H. J. L ubatti,139 C. L uci,133a,133b A. Lucotte,55 F. Luehring,61 W. Lukas,62 L. Lum inari,1333 O. Lundberg,1473,1476 B. Lund-Jensen,148

161801-10

PRL 114, 161801 (2015)

PHYSICAL

REVIEW

LETTERS

week ending

24 APRIL 2015

M. Lungw itz,83 D. Lynn,25 R. Lysak,127 E. Lytken,81 H. M a,25 L .L . M a,33d G. M accarrone,47 A. M acchiolo,101 J. M achado M iguens,126a,126b D. M acina,30 D. M adaffari,85 R. M adar,34 H .J. M addocks,72 W. F. M ader,44 A. M adsen,167 T. M aeno,25 A. M aevskiy," E. M agradze,54 K. M ahboubi,48 J. M ahlstedt,107 S. M ahm oud,74 C. M aiani,137 C. M aidantchik,243 A. A. M aier,101 A. M aio,126a,126b,126d S. M ajew ski,116 Y. M akida,66 N. M akovec,117 B. M alaescu,80 Pa. M alecki,39 V. P. M aleev,123 F. M alek,55 U. M allik,63 D. M alon,6 C. M alone,144 S. M altezos,10 V .M . M alyshev,109 S. M alyukov,30 J. M am uzic,42 B. M andelli,30 L. M andelli,913 I. M andic,75 R. M andrysch,63 J. M aneira,126a’126b A.

M anfredini,101 L. M anhaes de A ndrade Filho,241’ J. ManjaiTes R am os,160b A. M ann,100 P. M. M anning,138

A. M anousakis-K atsikakis,9 B. M ansoulie,137 R. M antifel,87 M. M antoani,54 L. M apelli,30 L. M arch,146c G. M archiori,80 M. M arcisovsky,127 C. P. M arino,170 M. M arjanovic,13 F. M arroquim,24" S.P. M arsden,84 Z. M arshall,15 L. F. M arti,17 S. M arti-G arcia,168 B. M artin,90 T. A. M artin,171 V. J. M artin,46 B. M artin dit Latour,14 H. M artinez,137 M. M artinez,12,0 S. M artin-H augh,131 A. C. M artyniuk,78 M. M arx,139 F. M arzano,1333 A. M arzin,30 L. M asetti,83 T. M ashim o,156 R. M ashinistov,96 J. M asik,84 A. L. M aslennikov,109,d I. M assa,20a,20b L. M assa,20a,20b N. M assol,5 P. M astrandrea,149 A. M astroberardino,373,376 T. M asubuchi,156 P. M attig,176 J. M attm ann,83 J. M aurer,26,1 S. J. M axfield,74 D. A. M axim ov,l09’d R. M azini,152 S .M . M azza,91a,91b L. M azzaferro,134a,134b G. M e G oldrick,159 S.P. Me Kee,89 A. M cC am ,89 R .L . M cCarthy,149 T. G. M cCarthy,29 N. A. M cC ubbin,131 K .W . M cFarlane,56,3 J. A. M cfayden,78 G. M chedlidze,54 S. J. M cM ahon,131 R. A. M cPherson,170,k J. M echnich,107 M. M edinnis,42 S. M eehan,1463 S. M ehlhase,100 A. M ehta,74 K. M eier,583 C. M eineck,100 B. M eirose,41 C. M elachrinos,31 B. R. M ellado G arcia,146c F. M eloni,17 A. M engarelli,20a,20b S. M enke,101 E. M eoni,162 K. M. M ercurio,57 S. M ergelmeyer,21 N. M eric,137 P. M erm od,49 L. M erola,104a,104b C. M eroni,913 F. S. M erritt,31 H. M erritt,111 A. M essina,30,33 J. M etcalfe,25 A. S. M ete,164 C. M eyer,83 C. M eyer,122 J-P. M eyer,137 J. M eyer,107 R. P. M iddleton,131 S. M igas,74 S. M iglioranzi,165a,165t L. M ijovic,21 G. M ikenberg,173 M. M ikestikova,127 M. M ikuz,75 A. M ilic,30 D. W. M iller,31 C. M ills,46 A. M ilov,173 D. A. M ilstead,147a,147b A. A. M inaenko,130 Y. M inam i,156 L A . M inashvili,65 A. I. M incer,110 B. M indur,383 M. Mineev,65 Y. M ing,174 L. M. M ir,12 G. M irabelli,1333 T. M itani,172 J. M itrevski,100 V. A. M itsou,168 A. M iucci,49 P. S. M iyagaw a,140 J. U. M jom m ark,81 T. M oa,147a,147b K. M ochizuki,85 S. M ohapatra,35 W. M ohr,48 S. M olander,147a,147b R. M oles-Valls,168 K. M onig,42 C. M onini,55 J. M onk,36 E. M onnier,85 J. M ontejo B erlingen,12 F. M onticelli,71 S. M onzani,133a,I33b R. W. M oore,3 N. M orange,117 D. M oreno,163 M. M oreno Llacer,54 P. M orettini,503 M. M orgenstem ,44 M. M orii,57 V. M orisbak,119 S. M oritz,83 A. K. M orley,148 G. M om acchi,30 J. D. M orris,76 A. M orton,53 L. M orvaj,103 H. G. M oser,101 M. M osidze,516 J. M oss,111 K. M otohashi,158 R. M ount,144 E. M ountricha,23 S. V. M ouraviev,96,3 E. J. W. M oyse,86 S. M uanza,85 R. D. M udd,18 F. M ueller,101 J. M ueller,125 K. M ueller,21 R. S. P. M ueller,100 T. M ueller,28 D. M uensterm ann 49 P. M ullen,53 Y. M unw es,154 J. A. M urillo Q uijada,18 W. J. M urray,171131 H. M usheghyan,54 E. M usto,153 A. G. M yagkov,130,bb M. M yska,128 O. N ackenhorst,54 J. Nadal,54 K. N agai,120 R. N agai,158 Y. N agai,85 K. N agano,66 A. N agarkar,111 Y. Nagasaka,59 K. N agata,161 M. N agel,101 E. Nagy,85 A. M. Nairz,30 Y. N akaham a,30 K. N akam ura,66 T. N akam ura,156 I. N akano,112 H. N am asivayam ,41 G. Nanava,21 R. F. Naranjo Garcia,42 R. N arayan,586 T. N atterm ann,21 T. Naum ann,42 G. N avarro,163 R. Nayyar,7 H. A. N eal,89 P. Yu. Nechaeva,96 T. J. N eep,84 P. D. N ef,144 A. N egri,121a,121b M. Negrini,203 S. N ektarijevic,106 C. N ellist,117 A. N elson,164 S. N em ecek,127 P. N em ethy,110 A. A. N epom uceno,243 M. N essi,30,cc M. S. N eubauer,166 M. N eum ann,176 R. M. N eves,110 P. N evski,25 P. R. N ew m an,18 D. H. N guyen,6 R. B. N ickerson,120 R. N icolaidou,137 B. Nicquevert,30 J. N ielsen,138 N. N ikiforou,35 A. N ikiforov,16 V. N ikolaenko,130,bb I. N ikolic-A udit,80 K. N ikolopoulos,18 P. N ilsson,25 Y. N inom iya,156 A. N isati,1333 R. N isius,101 T. N obe,158 M. N om achi,118 I. Nom idis,29 S. N orberg,113 M. N ordberg,30 O. N ovgorodova,44 S. N ow ak,101 M. N ozaki,66 L. N ozka,115 K. N tekas,10 G. Nunes Hanninger,88 T. N unnem ann,100 E. Nurse,78 F. N uti,88 B .J. O ’Brien,46 F. O ’grady,7 D. C. O ’N eil,143 V. O ’Shea,53 F. G. O akham ,29,6 H. O berlack,101 T. O berm ann,21 J. O cariz,80 A. Ochi,671. Ochoa,78 S. O da,70 S. O daka,66 H. O gren,61 A. O h,84 S. H. Oh,45 C. C. O h m ,15 H. O hm an,167 H. O ide,30 W. O kam ura,118 H. O kaw a,161 Y. O kum ura,31 T. O kuyam a,156 A. O lariu,263 A. G. Olchevski,65 S. A. Olivares Pino,46 D. Oliveira Dam azio,25 E. Oliver G arcia,168 A. O lszewski,39 J. O lszow ska,39 A. O nofre,126a,126e P .U .E . O nyisi,31,q C. J. O ram ,1603 M .J. Oreglia,31 Y. O ren,154 D. O restano,135a,135b N. O rlando,155 C. O ropeza Barrera,53 R. S. O rr,159 B. Osculati,50a,50b R. Ospanov,84 G. Otero y Garzon,27 H. O tono,70 M. O uchrif,136,1 E. A. O uellette,170 F. O uld-Saada,119 A. O uraou,137 K. P. O ussoren,107 Q. O uyang,33a A. O vcharova,15 M. O wen,53 V. E. O zcan,193 N. O zturk,8 K. Pachal,120 A. Pacheco Pages,12 C. Padilla A randa,12 M. Pagacova,48 S. Pagan G riso,15 E. Paganis,140 C. Pahl,101 F. Paige,25 P. Pais,86 K. Pajchel,119 G. Palacino,160b S. Palestini,30 M. Palka,38b D. Pallin,34 A. Palm a,l26a,126b Y. B. P a n ,174 E. Panagiotopoulou,10 C. E. Pandini,80 J. G. Panduro Vazquez,77 P. P ani,147a,147b

161801-11

PRL 114, 161801 (2015)

PHYSICAL

REVIEW

LETTERS

week ending

24 APRIL 2015

N. Panikashvili,89 S. Panitkin,25 L. Paolozzi,1343'1346 Th. D. Papadopoulou,10 K. Papageorgiou,133 A. Paramonov,6 D. Paredes H ernandez,155 M. A. Parker,28 K. A. Parker,140 F. Parodi,50a’50b J. A. Parsons,35 U. Parzefall,48 E. Pasqualucci,133a S. Passaggio,503 F. P astore,135a’l35b’a Fr. Pastore,77 G. Pasztor,29 S. Pataraia,176 N. D. Patel,151 J. R. Pater,84 T. Pauly,30 J. Pearce,170 L. E. Pedersen,36 M. P edersen,119 S. Pedraza L opez,168 R. Pedro, 126a , 126b s v Peleganchuk,109 D. Pelikan,167 H. Peng,336 B. Penning,31 J. Penw ell,61 D. V. Perepelitsa,25 E. Perez C odina,l60a M. T. Perez G arcla-Estan,168 L. Perini,9la’91b H. Pem egger,30 S. Perrella,l04a'l04b R. Peschke,42 V. D. Peshekhonov,65 K. Peters,30 R. F. Y. Peters,84 B. A. Petersen,30 T .C . Petersen,36 E. Petit,42 A. Petridis,147a’147b C. Petridou,155 E. Petrolo,133a F. Petrucci, 135a’135b N. E. Pettersson,158 R. Pezoa,3 6 P. W. P hillips,131 G. Piacquadio,144 E. Pianori,171 A. Picazio,49 E. Piccaro,76 M. Piccinini,20a'20b M. A. Pickering,120 R. Piegaia,27 D. T. Pignotti,1" J. E. Pilcher,31 A. D. Pilkington,78 J. Pina,

126a, 126b, 126d

M. Pinam onti,165a’165c’dd J. L. Pinfold,3 A. Pingel,36 B. Pinto,126a S. Pires,80 M. P itt,173 C. Pizio,91a’91b L. Plazak,145a 65 M.-A. Pleier,25 V. Pleskot,129 E. Plotnikova, P. P lucinski,i47a,147b D. Pluth,64 R. Poettgen,83 L. Poggioli, 17 D. Pohl,21 G. Polesello,l2la A. Policicchio,37a’37b R. Polifka,159 A. Polini,20a C. S. Pollard,53 V. Polychronakos,25 K. Pom m es,30 L. Pontecorvo,l33a B .G . Pope,90 G. A. Popeneciu,26b D. S. Popovic,13 A. Poppleton,30 S. Pospisil,128 K. Potam ianos,15 I. N. Potrap,65 C. J. Potter,150 C. T. Potter,116 G. Poulard,30 J. Poveda,30 V. Pozdnyakov,65 P. Pralavorio,85 A. Pranko,15 S. Prasad,5" S. Prell,64 D. Price,84 J. Price,74 L. E. Price,6 M. Primavera,73'1 S. Prince,87 M. Proissl,46 K. Prokofiev,60c F. Prokoshin,326 E. P rotopapadaki,137 S. Protopopescu,25 J. Proudfoot,6 M. Przybycien,383 E. Ptacek,116 D. Puddu,135a,135b E. Pueschel,86 D. P uldon,149 M. Purohit,25'ee P. Puzo,117 J, Q ian,89 G. Q in,53 Y. Q in,84 A. Q uadt,54 D. R. Q uarrie,15 W. B. Q uayle,l65a,l65b M. Q ueitsch-M aitland,84 D. Quilty,53 A. Q ureshi,160,1 V. Radeka,25 V. Radescu,42 S. K. R adhakrishnan,149 P. Radloff,116 P. R ados,88 F. Ragusa,913'916 G. R ahal,179 S. Rajagopalan,25 M. Ram m ensee,30 C. R angel-Sm ith,167 F. R auscher,100 S. Rave,83 T .C . Rave,48 T. Ravenscroft,53 M. Raym ond,30 A .L . R ead,119 N .P. Readioff,74 D. M. R ebuzzi,12laJ21b A. R edelbach,175 G. Redlinger,25 R. R eece,138 K. Reeves,41 L. R ehnisch,16 H. Reisin,27 M. R elich,164 C. Rem bser,30 H. Ren,33a A. R enaud.117 M. R escigno,133a S. Resconi,913 O. L. Rezanova,l09'd P. R eznicek,129 R. Rezvani,95 R. Richter,101 E. Richter-W as,38b M. Ridel,80 P. R ieck,16 C. J. R iegel,176 J. Rieger,54 M. R ijssenbeek,149 A. R im oldi,1213'1216 L. Rinaldi,203 E. Ritsch,621. R iu,12 F. R izatdinova,114 E. Rizvi,76 S. H. R obertson , 1ilM Roe,30 A. Robichaud-V eronneau,87 D. R obinson,28 J. E. M. R obinson,84 A. Robson,53 C. Roda, 1_4a. 1_4b ^ O. R p hne,119 S. R olli,16 A. R om aniouk,98 M. Rom ano,203'206 S. M. Rom ano Saez,34 E. Romero A dam ,168 N. R om potis,139 M. Ronzani,48 L. R oos,80 E. R os,168 S. R osati,133a K. Rosbach,48 P. R ose,138 P. L. R osendahl,14 O. R osenthal,142 V. R ossetti,1473' 1476 E. R ossi,1043' 1046 L. P. Rossi,50'1 R. R osten,139 M. Rotaru,"6'11. R oth,173 J. R othberg,19 D. R ousseau,117 C. R. R oyon,137 A. Rozanov,85 Y. R ozen,153 X. R uan,146c F. R ubbo,12 I. Rubinskiy,42 V. I. Rud,99 C. Rudolph,44 M. S. R udolph,159 F. Ruhr,48 A. R uiz-M artinez,30 Z. Rurikova,48 N. A. Rusakovich,65 A. R uschke,100 H. L. R ussell,139 J. P. Rutherfoord,7 N. R uthm ann,48 Y. F. Ryabov,123 M. Rybar,129 G. R ybkin,117 N. C. R yder,120 A. F. Saavedra,151 G. Sabato,107 S. Sacerdoti,27 A. Saddique,3 H. F-W. Sadrozinski,138 R. Sadykov,65 F. Safai Tehrani,1333 M. Saim pert,137 H. Sakam oto,156 Y. Sakurai,172 G. Salam anna,135a'135b A. S alam on,134a M. Saleem ,113 D. Salek,107 P. H. Sales De B ruin,139 37a,37b D. Salihagic,101 A. Salnikov,144 J. S alt,168 D. Salvatore, F. Salvatore,150 A. Salvucci,106 A. Salzburger,30 D. Sam psonidis,155 A. Sanchez,1043' 1046 J. Sanchez,168 V. Sanchez M artinez,168 H. Sandaker,14 R. L. Sandbach,76 H. G. Sander,83 M. P. Sanders,100 M. Sandhoff,176 C. Sandoval,163 R. Sandstroem ,101 D. P. C. Sankey,131 A. Sansoni,47 C. Santoni,34 R. S antonico,1343' 1346 H. Santos,1263 I. Santoyo C astillo,150 K. S app.125 A. Sapronov,65 J. G. Saraiva,126a,126d B. Sarrazin,^1 O. Sasaki,66 Y. Sasaki,156 K. S ato ,161 G. Sauvage,5'3 E. Sauvan,5 G. Savage,77 P. Savard,159'6 C. Saw yer,120 L. Sawyer,79'11D. H. Saxon,53 J. Saxon,31 C. S b a rra f0,1 A. Sbrizzi,203’06 T. Scanlon,78 D. A. Scannicchio,164 M. Scarcella,151 V. Scarfone,37a37b J. Schaarschm idt,173 P. Schacht,101 D. Schaefer,30 R. Schaefer,42 J. Schaeffer,83 S. Schaepe,21 S. Schaetzel,586 U. Schafer,83 A. C. Schaffer,117 D. S chaile,100 R. D. Scham berger,149 V. Scharf,583 V. A. Schegelsky,123 D. Scheirich,129 M. S chem au,164 C. Schiavi,50a'50b J. Schieck,100 C. Schillo,48 M. Schioppa,37a'37b S. Schlenker,30 E. Schm idt,48 K. Schm ieden,' 0 C. Schm itt,83 S. Schm itt,586 B. Schneider,1603 Y. J. Schnellbach,74 U. Schnoor,44 L. Schoeffel,1 7 A. Schoening,586 B. D. Schoenrock,90 A. L. S. Schorlemmer,54 M. Schott,83 D. Schouten,1603 J. Schovancova.8 S. Schram m ,159 M. Schreyer,17'5 C. Schroeder,83 N. Schuh,83 M. J. Schultens,21 H.-C. Schultz-Coulon,58a H. Schulz,16 M. Schum acher,48 B. A. Schum m ,138 Ph. Schune,137 C. Schwanenberger, 84 A. Schw artzm an,144 T. A. Schw arz,89 Ph. Schw egler,101 Ph. Schw em ling,137 R. Schwienhorst,90 J. Schw indling,137 T. Schw indt,21 42 ■ 123 . 89 M. Schwoerer,'5 F. G. Sciacca,17 E. Scifo,n / G. Sciolla,23 F. Scuri, 124a, 124b F. Scutti,21 J. Searcy,sy G. Sedov,42 E. Sedykh, P. Seem a,21 S. C. S eidel,105 A. S eiden,138 F. Seifert,128 J. M. Seixas,243 G. Sekhniaidze,1043 S. J. Sekula,40 K. E. Selbach,46

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LETTERS

week ending

24 APRIL 2015

M. Seliverstov,123,3 N. Sem prini-Cesari,20a'20b C. Serfon,30 L. Serin,117 L. Serkin,54 T. Seine,85 R. Seuster,160a

H. Severini,113 T. Sfiligoj,75 F. Sforza,101 A. Sfyrla,30 E. Shabalina,54 M. Sham im ,116 L. Y. Shan,33a R. Shang,166 J.T . Shank,22 M. Shapiro,15 P.B. Shatalov,97 K. Shaw,165a,165b A. Shcherbakova,l47a’l47b C .Y . Shehu,150 P. Sherw ood,78 L.

S hi,15211 S. Shim izu,67 C. O. Shim m in,164 M. Shim ojim a,102 M. Shiyakova,65 A. Shmeleva,96 D. Shoaleh Saadi,95 M .J. Shochet,31 S. Shojaii,91a’91b S. Shrestha,111 E. Shulga,98 M. A. Shupe,7 S. Shushkevich,42 P. Sicho,127

O. Sidiropoulou,175 D. Sidorov,114 A. Sidoti,20a 20b F. Siegert,44 Dj. Sijacki,13 J. Silva,l26a l26d Y. Silver,154 D. Silverstein,144 S. B. Silverstein,147d V. S im ak,128 O. Sim ard,5 Lj. Sim ic,13 S. Sim ion,117 E. Simioni,83 B. Sim m ons,78 D. Sim on,34 R. Sim oniello,91a,91b P. Sinervo,159 N. B. Sinev,116 G. Siragusa,175 A. Sircar,79 A. N. Sisakyan,65,3 S. Yu. Sivoklokov," J. Sjolin,1473,1476 T .B . Sjursen,14 M. B. Skinner,72 H. P. Skottowe,57 P. Skubic,113 M. Slater,18 T. Slavicek,128 M. Slaw inska,107 K. S liw a,162 V. Sm akhtin,17' B .H . Smart,46 L. Sm estad,14 S. Yu. Smirnov,98 Y. Smirnov,98 L. N. Sm irnova,99'gg O. Sm irnova,81 K. M. Sm ith,53 M. Smith,35 M. Sm izanska,72 K. Sm olek,128 A. A. Snesarev,96 G.

Snidero,76 S. Snyder,25 R. Sobie,170’k F. Socher,44 A. Soffer,154 D. A. Soh,152’ff C. A. Solans,30 M. Solar,128 J. Sole,128

E. Yu. Soldatov,98 U. Soldevila,168 A. A. Solodkov,130 A. Soloshenko,65 O. V. Solovyanov,130 V. Solovyev,123 P. Sommer,48 H. Y. Song,33b N. Soni,1 A. Sood,15 A. Sopczak,128 B. Sopko,128 V. Sopko,128 V. Sorin,12 D. Sosa,58b M. Sosebee,8 C. L. Sotiropoulou,155 R. Soualah,165a l65c P. Soueid,95 A. M. Soukharev,l09 d D. South,42 S. Spagnolo,73d,73b F. Spano,77 W. R. Spearman,57 F. Spettel,101 R. Spighi,20a G. Spigo,30 L. A. Spiller,88 M. Spousta,129 T. Spreitzer,159 R. D. St. Denis,53,3 S.

Staerz,44 J. Stahlm an,122 R. Stam en,583 S. Stam m ,16 E. Stanecka,39 C. Stanescu,l35a M. Stanescu-Bellu,42

M. M. Stanitzki,42 S. Stapnes,119 E. A. Starchenko,130 J. Stark.55 P. Staroba,127 P. Starovoitov,42 R. Staszewski,39 P. Stavina,145a,a P. Steinberg,25 B. Stelzer,143 H. J. Stelzer,30 O. Stelzer-Chilton,1603 H. Stenzel,52 S. S tem ,101 G. A. Stewart,53 J. A. Stillings,21 M. C. Stockton,87 M. Stoebe,87 G. Stoicea,263 P. Stolte,54 S. Stonjek,101 A. R. Stradling,8 A. Straessner 44 M. E. Stram aglia,17 J. Strandberg,148 S. Strandberg,1473,1476 A. Strandlie,119 E. Strauss,144 M. Strauss,113 P. Strizenec,1456 R. Strohm er,175 D. M. Strom ,116 R. Stroynowski,40 A. Strubig,106 S. A. Stucci,17 B. Stugu,14N. A. Styles 42 D. S u,144 J. S u,125 R. Subram aniam ,79 A. Succurro,12 Y. S ugaya,118 C. Suhr,108 M. S uk,128 V. V. Sulin,96 S. Sultansoy,4c T. Sum ida,68 S. Sun,57 X. Sun,33a J. E. Sunderm ann,48 K. Sum liz,150 G. Susinno,37a,37b M. R. Sutton,150 Y. Suzuki,66 M. Svatos,127 S. Sw edish,169 M. Sw iatlow ski,144 I. Sykora,1453 T. Sykora,129 D. Ta,90 C. Taccini,1353,1356 K. Tackmann,42 J. Taenzer,159 A. Taffard,164 R. Tafirout,1603 N. Taiblum ,154 H. Takai,25 R. Takashima,69 H. Takeda,67 T. Takeshita,141 Y. Takubo,66 M. Talby,85 A. A. Talyshev,109’d J. Y. C. Tam ,175 K. G. Tan,88 J. Tanaka,156 R. Tanaka,117 S. Tanaka,132 S. Tanaka,66 A. J. Tanasijczuk,143 B. B. Tannenw ald,111 N. Tannoury,21 S. Tapprogge,83 S. Tarem ,153 F. Tarrade,29 G. F. Tartarelli.91,1 P. Tas,1”9 M. Tasevsky,1"7 T. Tashiro,68 E. Tassi,37a'37b A. Tavares D elgado,1263,1266 Y. Tayalati,136d F. E. Taylor,94 G. N. Taylor,88 W. Taylor,1606 F. A. Teischinger,30 M. Teixeira Dias C astanheira,76 P. Teixeira-Dias,77 K. K. Temming,48 H. Ten Kate,30 P. K. Teng,152 J. J. Teoh,118 F. Tepel,176 S. Terada,66 K. Terashi,156 J. Terron,82 S. Terzo,101 M. Testa,47 R. J. Teuscher,159,k J. Therhaag,21 T. Theveneaux-Pelzer,34 J. P. T hom as,18 J. Thom as-W ilsker,77 E. N. Thom pson,15 P. D. Thom pson.18 R. J. Thom pson,84 A. S. Thom pson,53 L. A. Thom sen,36 E. T hom son,122 M. Thom son,28 W. M. Thong,88 R. P. Thun,89,3 F. Tian,35 M .J. T ibbetts,15 R. E. Ticse Torres,85 V. O. Tikhomirov,96,hh Yu. A. Tikhonov,109 d S. Tim oshenko,98 E. Tiouchichine,85 P. T ipton,177 S. Tisserant,85 T. Todorov,5,3 S. Todorova-Nova,129 J. Tojo,70 S. Tokar,l45d K. Tokushuku,66 K. Tollefson,90 E. Tolley,57 L. Tom linson,84 M. Tom oto,103 L. Tom pkins,144’11 K. Tom s,105 N. D. Topilin,65 E. Torrence,116 H. Torres,143 E. Torro Pastor,168 J. Toth,85’jj F. Touchard,85 D. R. Tovey,140 H. L. T ran,117 T. Trefzger,175 L. Tremblet,30 A. Tricoli,30 I. M. Trigger,1603 S. Trincaz-D uvoid,80 M. F. Tripiana,12 W. Trischuk,159 B. Trocm e,55 C. Troncon,913 M. Trottier-M cD onald,15 M. Trovatelli,135a,135b P. True,90 M. Trzebinski,39 A. Trzupek.39 C. Tsarouchas,30 J. C-L. T seng,120 P. V. Tsiareshka,92 D. T sionou,137 G. T sipolitis,10 N. Tsirintanis,9 S. Tsiskaridze,12 V. Tsiskaridze 48 E. G. Tskhadadze,5' 3 1.1. Tsukerm an,97 V. T sulaia,15 S. Tsuno,66 D. Tsybychev,149 A. Tudorache,263 V. Tudorache,263 A. N. T una,1-2 S. A. Tupputi,203’206 S. T urch ik h in ,"’gg D. Turecek,128 I. Turk Cakir,4c R. Turra,9l3’91b A. J. Turvey,40 P. M. Tuts,35 A. Tykhonov,49 M. Tylm ad,1473’1476 M. Tyndel,131 I. U eda,156 R. Ueno,29 M. U ghetto,85 M. U gland,14 M. U hlenbrock,21 F. U kegaw a,161 G. U nal,30 A. U ndm s,25 G. U nel,164 F. C. Ungaro,48 Y. Unno,66 C. U nverdorben,100 J. U rban,1456 P. U rquijo,88 P. U rrejola,83 G. U sai,8 A. Usanova,62 L. Vacavant,85 V. V acek,1”8 B. Vachon,87 N. Valencic,107 S. Valentinetti,203,206 A. Valero,168 L. Valery,12 S. Valkar,129 E. Valladolid G allego,168 S. Vallecorsa,49 J. A. Vails Ferrer,168 W. Van Den W ollenberg,107 P. C. Van D er D eijl,107 R. van der G eer,107 H. van der G raaf,107 R. Van Der Leeuw ,107 N. van Eldik,30 P. van G em m eren,6 J. Van N ieuw koop,143 I. van V ulpen,107 M. C. van W oerden,30 M. Vanadia,1333’1336 W. Vandelli,30 R. Vanguri,122 A. Vaniachine,6 F. Vannucci,80 G. V ardanyan,178 R. Vari,133d E. W. Vames,7 T. Varol,40

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LETTERS

week ending 24 APRIL 2015

D. Varouchas,80 A. Vartapetian,8 K. E. Varvell,151 F. Vazeille,34 T. Vazquez Schroeder,54 J. Veatch,7 F. Veloso,126a'126c T. Velz,21 S. V eneziano,133a A. Ventura,73a,73b D. Ventura,86 M. Venturi,170 N. Venturi,159 A. Venturing23 V. Vercesi,12la M. V erducci,l33a'133b W. Verkerke,107 J .C . Verm eulen,107 A. Vest,44 M. C. Vetterli,143'e O. Viazlo,81 I. V ichou,166 T. Vickey,146c,kk O. E. Vickey B oeriu,146c G. H. A. Viehhauser,120 S. Viel,15 R. Vigne,30 M. Villa,20a’20b M. Villaplana Perez,91a'91b E. Vilucchi,47 M. G. Vincter,29 V. B, Vinogradov,67 J. Virzi,15 I. Vivarelli,150 F. Vives Vaque,3 S. V lachos,10 D. V ladoiu,100 M. V lasak,128 M. Vogel,32a P. Vokac,128 G. Volpi,124a’124b M. Volpi,88 H. von der Schm itt,101 H. von Radziew ski,48 E. von Toem e,21 V. Vorobei,129 K. Vorobev,98 M. Vos,168 R. Voss,30 J. H. Vossebeld,74 N. V ranjes,13 M. Vranjes M ilosavljevic,13 V. V rba,127 M. V reesw ijk,107 R. Vuillermet,30 I. Vukotic,31 Z. V ykydal,128 P. Wagner,21 W. W agner,176 H. W ahlberg,71 S. W ahrmund,44 J. W akabayashi,103 J. Walder,72 R. W alker,100 W. W alkowiak,142 C. W ang,33c F. W ang,174 H. W ang,15 H. Wang 40 J. W ang,42 J. W ang,33a K. W ang,87 R. W ang,105 S. M. W ang,152 T. W ang,21 X. W ang,177 C. W anotayaroj,"6 A. W arburton,87 C. P W ard,28 D. R. W ardrope,78 M. Warsinsky,48 A. W ashbrook,46 C. Wasicki,42 P.M . W atkins,18 A. T. W atson,18 I. J. W atson,151 M. F. W atson,18 G. W atts,139 S. Watts,84 B .M . W augh,78 S. W ebb,84 M. S. W eber,17 S. W. W eber,177 J. S. Webster,31 A. R. W eidberg,120 B. W einert,61 J. W eingarten,54 C. Weiser,48 H. W eits,107 P. S. W ells,30 T. W enaus,25 D. W endland,16 T. W engler,30 S. W enig,30 N. W ermes,21 M. Werner,48 P. Werner,30 M. W essels,58a J. W etter,162 K. W halen,29 A. M. W harton,72 A. W hite,8 M .J. W hite,1 R. W hite,326 S. W hite,124a'124b D. W hiteson,164 D. W icke,176 F. J. W ickens,131 W. W iedenm ann,174 M. W ielers,131 P. W ienem ann,21 C. W iglesworth,36 L. A. M. W iik-Fuchs,21 A. W ildauer,101 H. G. W ilkens,30 H. H. W illiam s,122 S. W illiam s,107 C. W illis,90 S. W illocq,86 A. W ilson,89 J. A. W ilson,18 I. W ingerter-Seez,5 F. W inklm eier,116 B.T. W inter,21 M. W ittgen,144 J. W ittkow ski,100 S. J. W ollstadt,83 M. W. W olter,39 H. W olters,126a’126c B. K. W osiek,31 J. W otschack,30 M. J. W oudstra,84 K. W. W ozniak,39 M. W u,55 S. L. W u,174 X. W u,49 Y. W u,89 T. R. W yatt,84 B. M. W ynne,46 S. Xella,36 D. X u,33a L. X u,336'" B. Yabsley,151 S. Y acoob,1466 "11'1 R. Yakabe,67 M. Yamada,66 Y. Y am aguchi,118 A. Yamamoto,66 S. Yam am oto,156 T. Yam anaka,176 K. Yam auchi,103 Y. Yamazaki,67 Z. Yan,22 H. Yang,33e H. Y ang,174 Y. Y ang,152 S. Yanush,93 L. Yao,33a W-M. Yao,15 Y. Yasu,66 E. Yatsenko,42 K. H. Yau W ong,21 J. Ye,40 S. Ye,25 I. Yeletskikh,65 A. L. Yen,57 E. Yildirim,42 K. Yorita,172 R. Yoshida,6 K. Y oshihara,122 C. Young,144 C. J. S. Young,30 S. Youssef,22 D. R. Yu,15 J. Yu,8 J. M. Yu,89 J. Yu,114 L. Yuan,67 A. Yurkewicz,108 I. Yusuff,28'"" B. Zabinski,39 R. Z a id a n 63 A. M. Zaitsev, 130'bb A. Zam an,149 S. Zam bito,23 L. Z anello,I33a,I33b D. Z anzi,88 C. Z eitnitz,176 M. Zernan,128 A. Zem la,38a K. Zengel,23 O. Z enin,130 T. Z enis,145a D. Z erw as,"7 D. Z hang,89 F. Z hang,174 J. Zhang,6 L. Z hang,152 R. Z hang,336 X. Zhang,33d Z. Z hang,117 X. Zhao,40 Y. Zhao,33d Z. Zhao,336 A. Zhem chugov,65 J. Z hong,120 B. Zhou,89 C. Zhou,45 L. Zhou,35 L. Zhou 40 N. Z h o u ,164 C .G . Zhu,33d H. Zhu,33a J. Z hu,89 Y. Zhu,33b X. Zhuang,33a K. Zhukov,96 A. Zibell,175 D. Ziem inska,61 N. I. Zim ine,65 C. Zim m erm ann,83 R. Zim m erm ann,21 S. Zim m erm ann 48 Z. Zinonos,54 M. Z iolkow ski,142 L. Z ivkovic,13 G. Zobernig,174 A. Zoccoli,20a’20b M. zur N edden,16 G. Zurzolo,104a,1H4b and L. Zwalinski30 (ATLAS Collaboration) 'Department o f Physics, University o f Adelaide, Adelaide, Australia 2Physics Department, SUNY Albany, Albany NY, United States o f America 3Department o f Physics, University o f Alberta, Edmonton AB, Canada 4aDepartment o f Physics, Ankara University, Ankara, Turkey 4hIstanbul Aydin University, Istanbul, Turkey LDivision o f Physics, TOBB University o f Economics and Technology, Ankara, Turkey 7LAPP, CNRS/IN2P3 and Universite de Savoie, Annecy-le-Vieux, France ’High Energy Physics Division, Argonne National Laboratory, Argonne IL, United States o f America Department o f Physics, University o f Arizona, Tucson AZ, United States o f America 'Department o f Physics, The University o f Texas at Arlington, Arlington TX, United States o f America Physics Department, University o f Athens, Athens, Greece Physics Department, National Technical University o f Athens, Zografou, Greece ^ Institute o f Physics, Azerbaijan Academy o f Sciences, Baku, Azerbaijan Institut de Fisica d ’Altes Energies and Departament de Fisica de la Universitat Autdnoma de Barcelona, Barcelona, Spain Institute o f Physics, University o f Belgrade, Belgrade, Serbia Department fo r Physics and Technology, University o f Bergen, Bergen, Norway Physics Division, Lawrence Berkeley National Laboratory and University o f California, Berkeley CA, United States o f America 5Department o f Physics, Humboldt University, Berlin, Germany Albert Einstein Center fo r Fundamental Physics and Laboratory fo r High Energy Physics, University o f Bern, Bern, Switzerland

161801-14

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LETTERS

week ending 24 APRIL 2015

18School o f Physics and Astronomy, University o f Birmingham, Birmingham, United Kingdom ^ ‘'Department o f Physics, Bogazici University, Istanbul, Turkey l9bDepartment o f Physics, Dogus University, Istanbul, Turkey l9tDepartment o f Physics Engineering, Gaziantep University, Gaziantep, Turkey 20aINFN Sezione di Bologna, Italy "obDipartimento di Fisica e Astronomia, Universita di Bologna, Bologna, Italy 21Physikalisches Institut, University o f Bonn, Bonn, Germany 22Department o f Physics, Boston University, Boston MA, United States o f America 23Department o f Physics, Brandeis University, Waltham MA, United States o f America 24aUniversidade Federal do Rio De Janeiro COPPE/EE/IF, Rio de Janeiro, Brazil 24bElectrical Circuits Department, Federal University o f Juiz de Fora (UFJF), Juiz de Fora, Brazil 24cFederal University o f Sao Joao del Rei (UFSJ), Sao Joao del Rei, Brazil 24AInstituto de Fisica, Universidade de Sao Paulo, Sao Paulo, Brazil 25Physics Department, Brookhaven National Laboratory, Upton NY, United States o f America 2baNational Institute o f Physics and Nuclear Engineering, Bucharest, Romania 2bbNational Institute for Research and Development o f Isotopic and Molecular Technologies, Physics Department, Cluj Napoca, Romania 26cUniversity Politehnica Bucharest, Bucharest, Romania 2MWest University in Timisoara, Timisoara, Romania 27Departamento de Fisica, Universidad de Buenos Aires, Buenos Aires, Argentina 2t,Cavendish Laboratory, University o f Cambridge, Cambridge, United Kingdom 29Department o f Physics, Carleton University, Ottawa ON, Canada i0CERN, Geneva, Switzerland 31Enrico Fermi Institute, University o f Chicago, Chicago IL, United States o f America 32aDepartamento de Fisica, Pontificia Universidad Catolica de Chile, Santiago, Chile 32bDepartamento de Fisica, Universidad Tecnica Federico Santa Maria, Valparaiso, Chile 33aInstitute o f High Energy Physics, Chinese Academy o f Sciences, Beijing, China 33hDepartment o f Modem Physics, University o f Science and Technology o f China, Anhui, China 33cDepartment o f Physics, Nanjing University, Jiangsu, China i3dSchool o f Physics, Shandong University, Shandong, China 33eDepartment o f Physics and Astronomy, Shanghai Key Laboratory fo r Particle Physics and Cosmology, Shanghai Jiao Tong University, Shanghai, China 33fPhysics Department, Tsinghua University, Beijing 100084, China 34Laboratoire de Physique Corpusculaire, Clermont Universite and Universite Blaise Pascal and CNRS/IN2P3, Clermont-Ferrand, France 35Nevis Laboratory, Columbia University, Irvington NY, United States o f America 36Niels Bohr Institute, University o f Copenhagen, Kobenhavn, Denmark 37aINFN Gruppo Collegato di Cosenza, Laboratori Nazionali di Frascati, Italy 37bDipartimento di Fisica, Universita della Calabria, Rende, Italy iSaAGH University o f Science and Technology, Faculty o f Physics and Applied Computer Science, Krakow, Poland 'm Marian Smoluchowski Institute o f Physics, Jagiellonian University, Krakow, Poland 39The Henryk Niewodniczanski Institute o f Nuclear Physics, Polish Academy o f Sciences, Krakow, Poland 411Physics Department, Southern Methodist University, Dallas TX, United States o f America 41Physics Department, University o f Texas at Dallas, Richardson TX, United States o f America 42DESY, Hamburg and Zeuthen, Germany 43Institut fu r Experimented Physik IV, Technische Universitat Dortmund, Dortmund, Germany 44Institut fu r Kem- und Teilchenphysik, Technische Universitat Dresden, Dresden, Germany 45Department o f Physics, Duke University, Durham NC, United States o f America 46SUPA-School o f Physics and Astronomy, University o f Edinburgh, Edinburgh, United Kingdom 41INFN Laboratori Nazionali di Frascati, Frascati, Italy 4SFakultat fu r Mathematik und Physik, Albert-Ludwigs-Universitat, Freiburg, Germany 49Section de Physique, Universite de Geneve, Geneva, Switzerland 50aINFN Sezione di Genova, Italy 50bDipartimento di Fisica, Universita di Genova, Genova, Italy 5laE. Andronikashvili Institute o f Physics, Iv. Javakhishvili Tbilisi State University, Tbilisi, Georgia 5]bHigh Energy Physics Institute, Tbilisi State University, Tbilisi, Georgia 52II Physikalisches Institut, Justus-Liebig-Universitdt Giessen, Giessen, Germany b3SUPA-School o f Physics and Astronomy, University o f Glasgow, Glasgow, United Kingdom 54II Physikalisches Institut, Georg-August-Universitat, Gottingen, Germany 55Laboratoire de Physique Subatomique et de Cosmologie, Universite Grenoble-Alpes, CNRS/IN2P3, Grenoble, France

161801-15

PRL 114, 161801 (2015)

PHYSICAL

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LETTERS

week ending

24 APRIL 2015

56Department o f Physics, Hampton University, Hampton VA, United States o f America 5 Laboratory fo r Particle Physics and Cosmology, Harvard University, Cambridge MA, United States o f America Kirchhoff-lnstitut fu r Physik, Ruprecht-Karls-Universitdt Heidelberg, Heidelberg, Germany 5HbPhysikalisches Institut, Ruprecht-Karls-Universitdt Heidelberg, Heidelberg, Germany ZITI Institut fu r technische lnformatik, Ruprecht-Karls-Universitdt Heidelberg, Mannheim, Germany Faculty o f Applied Information Science, Hiroshima Institute o f Technology, Hiroshima, Japan 60aDepartment o f Physics, The Chinese University o f Hong Kong, Shatin, N.T., Hong Kong, China bDepartment o f Physics, The University o f Hong Kong, Hong Kong, China 6 1Department o f Physics, The Hong Kong University o f Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Department o f Physics, Indiana University, Bloomington IN, United States o f America "Institut fu r Astro-und Teilchenphysik, Leopold-Franzens-Universitat, Innsbruck, Austria University o f Iowa, Iowa City I A, United States o f America 1 Department o f Physics and Astronomy, Iowa State University, Ames IA, United States o f America b>Joint Institute fo r Nuclear Research, JINR Dubna, Dubna, Russia KEK, High Energy Accelerator Research Organization, Tsukuba, Japan Graduate School o f Science, Kobe University, Kobe, Japan 68Faculty o f Science, Kyoto University, Kyoto, Japan 69Kyoto University o f Education, Kyoto, Japan 10Department o f Physics, Kyushu University, Fukuoka, Japan 71Instituto de Fisica La Plata, Universidad Nacional de La Plata and CONICET, La Plata, Argentina ~Physics Department, Lancaster University, Lancaster, United Kingdom 13dINFN Sezione di Lecce, Italy Dipartimento di Matematica e Fisica, Universita del Salento, Lecce, Italy Oliver Lodge Laboratory, University o f Liverpool, Liverpool, United Kingdom Department o f Physics, Jozef Stefan Institute and University o f Ljubljana, Ljubljana, Slovenia School o f Physics and Astronomy, Queen Mary University o f London, London, United Kingdom Department o f Physics, Royal Holloway University o f London, Surrey, United Kingdom Department o f Physics and Astronomy, University College London, London, United Kingdom Louisiana Tech University, Ruston LA, United States o f America Laboratoire de Physique Nucleaire et de Hautes Energies, UPMC and Universite Paris-Diderot and CNRS/IN2P3, Paris, France Fysiska institutionen, Lunds universitet, Lund, Sweden 82 "Departamento de Fisica Teorica C-I5, Universidad Autonoma de Madrid, Madrid, Spain Institut fu r Physik, Universitat Mainz, Mainz, Germany School o f Physics and Astronomy, University o f Manchester, Manchester, United Kingdom 85CPPM, Aix-Marseille Universite and CNRS/IN2P3, Marseille, France 86Department o f Physics, University o f Massachusetts, Amherst MA, United States o f America Department o f Physics, McGill University, Montreal QC, Canada School o f Physics, University o f Melbourne, Victoria, Australia 1 Department o f Physics, The University o f Michigan, Ann Arbor MI, United States o f America Department o f Physics and Astronomy, Michigan State University, East Lansing MI, United States o f America >UINFN Sezione di Milano, Italy 9 1b Dipartimento di Fisica, Universita di Milano, Milano, Italy B L Stepanov Institute o f Physics, National Academy o f Sciences o f Belarus, Minsk, Republic o f Belarus National Scientific and Educational Centre fo r Particle and High Energy Physics, Minsk, Republic o f Belarus 94Department o f Physics, Massachusetts Institute o f Technology, Cambridge MA, United States o f America ~Group o f Particle Physics, University o f Montreal, Montreal QC, Canada P.N. Lebedev Institute o f Physics, Academy o f Sciences, Moscow, Russia Institute fo r Theoretical and Experimental Physics (ITEP), Moscow, Russia National Research Nuclear University MEPhI, Moscow, Russia D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow, Russia Fakultdt fu r Physik, Ludwig-Maximilians-Universitat Miinchen, Miinchen, Germany Max-Planck-Institut fu r Physik (Werner-Heisenberg-Institut), Miinchen, Germany Nagasaki Institute o f Applied Science, Nagasaki, Japan Graduate School o f Science and Kobayashi-Maskawa Institute, Nagoya University, Nagoya, Japan m *INFN Sezione di Napoli, Italy bDipartimento di Fisica, Universita di Napoli, Napoli, Italy Department o f Physics and Astronomy, University o f New Mexico, Albuquerque NM, United States o f America Institute fo r Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen/Nikhef Nijmegen, Netherlands Nikhef National Institute fo r Subatomic Physics and University o f Amsterdam, Amsterdam, Netherlands 108Department o f Physics, Northern Illinois University, DeKalb IL, United States o f America

161801-16

PRL 114, 161801 (2015)

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week ending 24 APRIL 2015

i09Budker Institute o f Nuclear Physics, SB RAS, Novosibirsk, Russia 110Department o f Physics, New York University, New York NY, United States o f America "'O hio State University, Columbus OH, United States o f America 112 Faculty o f Science, Okayama University, Okayama, Japan 113Homer L. Dodge Department o f Physics and Astronomy, University o f Oklahoma, Norman OK, United States o f America 114Department o f Physics, Oklahoma State University, Stillwater OK, United States o f America U5Palacky University, RCPTM, Olomouc, Czech Republic 116Center fo r High Energy Physics, University o f Oregon, Eugene OR, United States o f America U1LAL, Universite Paris-Sud and CNRS/IN2P3, Orsay, France 118Graduate School o f Science, Osaka University, Osaka, Japan 119Department o f Physics, University o f Oslo, Oslo, Norway 120Department o f Physics, Oxford University, Oxford, United Kingdom l2ldINFN Sezione di Pavia, Italy 1~lbDipartimento di Fisica, Universita di Pavia, Pavia, Italy 122Department o f Physics, University o f Pennsylvania, Philadelphia PA, United States o f America 1-3Petersburg Nuclear Physics Institute, Gatchina, Russia l24iINFN Sezione di Pisa, Italy 124bDipartimento di Fisica E. Fermi, Universita di Pisa, Pisa, Italy l2>Department o f Physics and Astronomy, University o f Pittsburgh, Pittsburgh PA, United States o f America maLaboratorio de Instrumentacao e Fisica Experimental de Particulas-LIP, Lisboa, Portugal mbFaculdade de Ciencias, Universidade de Lisboa, Lisboa, Portugal l26cDepartment o f Physics, University o f Coimbra, Coimbra, Portugal nMCentro de Fisica Nuclear da Universidade de Lisboa, Lisboa, Portugal ]26eDepartamento de Fisica, Universidade do Minho, Braga, Portugal l26fDepartamento de Fisica Teorica y del Cosmos and CAFPE, Universidad de Granada, Granada, Spain l26gDep Fisica and CEFITEC o f Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal 127Institute o f Physics, Academy o f Sciences o f the Czech Republic, Praha, Czech Republic m Czech Technical University in Prague, Praha, Czech Republic 129Faculty o f Mathematics and Physics, Charles University in Prague, Praha, Czech Republic 130State Research Center Institute fo r High Energy Physics, Protvino, Russia 131Particle Physics Department, Rutherford Appleton Laboratory, Didcot, United Kingdom ~Ritsumeikan University, Kusatsu, Shiga, Japan 12211INFN Sezione di Roma, Italy l33bDipartimento di Fisica, Sapienza Universita di Roma, Roma, Italy l34‘7NFN Sezione di Roma Tor Vergata, Italy l34hDipartimento di Fisica, Universita di Roma Tor Vergata, Roma, Italy l35dINFN Sezione di Roma Tre, Italy i35bDipartimento di Matematica e Fisica, Universita Roma Tre, Roma, Italy mdFaculte des Sciences Ain Chock, Reseau Universitaire de Physique des Hautes Energies-Universite Hassan II, Casablanca, Morocco i36bCentre National de I’Energie des Sciences Techniques Nucleaires, Rabat, Morocco l36cFaculte des Sciences Semlalia, Universite Cadi Ayyad, LPHEA-Marrakech, Morocco l36dFaculte des Sciences, Universite Mohamed Premier and LPTPM, Oujda, Morocco ubeFaculte des sciences, Universite Mohammed V-Agdal, Rabat, Morocco 137DSM/IRFU (Institut de Recherches sur les Lois Fondamentales de I'Univers), CEA Saclay (Commissariat a I ’Energie Atomique et aux Energies Alternatives), Gif-sur-Yvette, France 138Santa Cruz Institute fo r Particle Physics, University o f California Santa Cruz, Santa Cruz CA, United States o f America 139Department o f Physics, University o f Washington, Seattle WA, United States o f America 140Department o f Physics and Astronomy, University o f Sheffield, Sheffield, United Kingdom 141Department o f Physics, Shinshu University, Nagano, Japan H2Fachbereich Physik, Universitat Siegen, Siegen, Germany 143Department o f Physics, Simon Fraser University, Burnaby BC, Canada H4SLAC National Accelerator Laboratory, Stanford CA, United States o f America '45dFaculty o f Mathematics, Physics & Informatics, Comenius University, Bratislava, Slovak Republic l45bDepartment o f Subnuclear Physics, Institute o f Experimental Physics o f the Slovak Academy o f Sciences, Kosice, Slovak Republic i4bdDepartment o f Physics, University o f Cape Town, Cape Town, South Africa 146bDepartment o f Physics, University o f Johannesburg, Johannesburg, South Africa 146cSchool o f Physics, University o f the Witwatersrand, Johannesburg, South Africa '41dDepartment o f Physics, Stockholm University, Sweden

161801-17

PRL 114, 161801 (2015)

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week ending 24 APRIL 2015

ulbThe Oskar Klein Centre, Stockholm, Sweden 148Physics Department, Royal Institute o f Technology, Stockholm, Sweden 4JDepartments o f Physics & Astronomy and Chemistry, Stony Brook University, Stony Brook NY, United States o f America Department o f Physics and Astronomy, University o f Sussex, Brighton, United Kingdom 1 5 1 School o f Physics, University o f Sydney, Sydney, Australia i5~Institute o f Physics, Academia Sinica, Taipei, Taiwan x Department o f Physics, Technion: Israel Institute o f Technology, Haifa, Israel 5 Raymond and Beverly Sackler School o f Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel Department o f Physics, Aristotle University o f Thessaloniki, Thessaloniki, Greece International Center fo r Elementary Particle Physics and Department o f Physics, The University o f Tokyo, Tokyo, Japan 51Graduate School o f Science and Technology, Tokyo Metropolitan University, Tokyo, Japan Department o f Physics, Tokyo Institute o f Technology, Tokyo, Japan 154Department o f Physics, University o f Toronto, Toronto ON, Canada l60dTRIUMF, Vancouver BC, Canada l60bDepartment o f Physics and Astronomy, York University, Toronto ON, Canada Faculty o f Pure and Applied Sciences, University o f Tsukuba, Tsukuba, Japan 162Department o f Physics and Astronomy, Tufts University, Medford MA, United States o f America Centro de Investigaciones, Universidad Antonio Narino, Bogota, Colombia Department o f Physics and Astronomy, University o f California Irvine, Irvine CA, United States o f America ' aINFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy l65bICTP, Trieste, Italy ib^Dipartimento di Chimica, Fisica e Ambiente, Universita di Udine, Udine, Italy 66Department o f Physics, University o f Illinois, Urbana IL, United States o f America Department o f Physics and Astronomy, University o f Uppsala, Uppsala, Sweden Instituto de Fisica Corpuscular (IFIC) and Departamento de Fisica Atomica, Molecular y Nuclear and Departamento de Ingenierla Electronica and Instituto de Microelectronica de Barcelona (IMB-CNM), University o f Valencia and CSIC, Valencia, Spain ’ Department o f Physics, University o f British Columbia, Vancouver BC, Canada ’Department o f Physics and Astronomy, University o f Victoria, Victoria BC, Canada Department o f Physics, University o f Warwick, Coventry, United Kingdom ll'Waseda University, Tokyo, Japan Department o f Particle Physics, The Weizmann Institute o f Science, Rehovot, Israel Department o f Physics, University o f Wisconsin, Madison WI, United States o f America Fakultat fu r Physik und Astronomie, Julius-Maximilians-Universitat, Wurzburg, Germany Fachbereich C Physik, Bergische Universitat Wuppertal, Wuppertal, Germany 7 Department o f Physics, Yale University, New Haven CT, United States o f America 178Yerevan Physics Institute, Yerevan, Armenia Centre de Calcul de I’Institut National de Physique Nucleaire et de Physique des Pcirticules (IN2P3), Villeurbanne, France JDeceased. '’Also at Department of Physics, King’s College London. London, United Kingdom. ’Also at Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan. c,Also at Novosibirsk State University, Novosibirsk, Russia. ’Also at TRIUMF, Vancouver BC, Canada. 'Also at Department of Physics, California State University, Fresno CA, United States of America. 8Also at Department of Physics, University of Fribourg, Fribourg, Switzerland. hAlso at Tomsk State University, Tomsk, Russia. ‘Also at CPPM, Aix-Marseille Universite and CNRS/IN2P3, Marseille, France. 'Also at Universita di Napoli Parthenope, Napoli, Italy. kAlso at Institute of Particle Physics (IPP), Canada. 'Also at Particle Physics Department, Rutherford Appleton Laboratory, Didcot, United Kingdom. "’Also at Department of Physics, St. Petersburg State Polytechnical University, St. Petersburg, Russia. "Also at Louisiana Tech University, Ruston LA, United States of America. “Also at Institucio Catalana de Recerca i Estudis Avancats, ICREA, Barcelona, Spain. pAlso at Department of Physics, National Tsing Hua University, Taiwan. qAlso at Department of Physics, The University of Texas at Austin, Austin TX, United States of America. rAIso at Institute of Theoretical Physics, Ilia State University, Tbilisi, Georgia. ’Also at CERN, Geneva, Switzerland. 'Also at Georgian Technical University (GTU),Tbilisi, Georgia.

161801-18

PRL 114, 161801 (2015)

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LETTERS

week ending

24 APRIL 2015

“Also at Ochadai Academic Production, Ochanomizu University, Tokyo, Japan. “Also at Manhattan College, New York NY, United States of America. wAlso at Institute of Physics, Academia Sinica, Taipei, Taiwan. xAlso at LAL, Universite Paris-Sud and CNRS/IN2P3, Orsay, France. yAlso at Academia Sinica Grid Computing, Institute of Physics, Academia Sinica, Taipei, Taiwan. zAlso at Laboratoire de Physique Nucleaire et de Hautes Energies, UPMC and Universite Paris-Diderot and CNRS/IN2P3, Paris, France. “ Also at Dipartimento di Fisica, Sapienza Universita di Roma, Roma, Italy. bbAlso at Moscow Institute of Physics and Technology State University, Dolgoprudny, Russia. “ Also at Section de Physique, Universite de Geneve, Geneva, Switzerland. ddAlso at International School for Advanced Studies (SISSA), Trieste, Italy. “ Also at Department of Physics and Astronomy, University of South Carolina, Columbia SC, United States of America. f,Also at School of Physics and Engineering, Sun Yat-sen University, Guangzhou, China. 88Also at Faculty of Physics, M.V.Lomonosov Moscow State University, Moscow, Russia. hbAlso at National Research Nuclear University MEPhI, Moscow, Russia. "Also at Department of Physics, Stanford University, Stanford CA, United States of America. 11Also at Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Budapest, Hungary. kkAlso at Department of Physics, Oxford University, Oxford, United Kingdom. "Also at Department of Physics, The University of Michigan, Ann Arbor MI, United States of America. mmAlso at Discipline of Physics, University of KwaZulu-Natal, Durban, South Africa. ""Also at University of Malaya, Department of Physics, Kuala Lumpur, Malaysia.

161801-19

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Search for Scalar Charm Quark Pair Production in pp Collisions at sqrt[s]=8  TeV with the ATLAS Detector.

The results of a dedicated search for pair production of scalar partners of charm quarks are reported. The search is based on an integrated luminosity...
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