Measurement of prompt psi(2S) to J/psi yield ratios in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV
EEUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN)
CERN-PH-EP/2013-0372018/10/16
CMS-HIN-12-007
Measurement of prompt ψ (2S) to J/ ψ yield ratios in PbPband pp collisions at √ s NN = The CMS Collaboration ∗ Abstract
The ratio between the prompt ψ (2S) and J/ ψ yields, reconstructed via their decaysinto µ + µ − , is measured in PbPb and pp collisions at √ s NN = µ b − and 5.4 pb − , respectively.The double ratio of measured yields, ( N ψ (2S) / N J/ ψ ) PbPb / ( N ψ (2S) / N J/ ψ ) pp , is computedin three PbPb collision centrality bins and two kinematic ranges: one at midrapid-ity, | y | < < p T <
30 GeV/ c ,and the other at forward rapidity, 1.6 < | y | < p T val-ues, 3 < p T <
30 GeV/ c . The centrality-integrated double ratio changes from0.45 ± ± ± ± Published in Physical Review Letters as doi:10.1103/PhysRevLett.113.262301. c (cid:13) ∗ See Appendix A for the list of collaboration members a r X i v : . [ nu c l - e x ] J a n The goal of the study of ultrarelativistic heavy-ion collisions is to create and characterize thequark-gluon plasma (QGP), a medium where quarks and gluons are no longer confined inhadrons [1]. Charmonia should dissociate when the Debye screening radius of this medium,which decreases with increasing QGP temperature, becomes smaller than the binding radiusof the charmonium state [2]. Since the ψ (2S) meson is less bound than the J/ ψ , it should melt atlower temperatures [3], an idea consistent with charmonium suppression measurements madeat the CERN SPS [4, 5]. At the CERN LHC, a suppression of J/ ψ mesons in PbPb collisions at acenter-of-mass energy per nucleon-nucleon pair of √ s NN = R AA , the ratio of nucleus-nucleus and ppcharmonium production yields normalized by the number of inelastic nucleon-nucleon colli-sions. The suppression increases with transverse momentum ( p T ), exhibiting a strong centralitydependence at high p T , but almost no dependence when integrated over p T . Related results atthe SPS and BNL RHIC are presented in Ref. [9] and references therein.Given the large number ( O ( ) ) of charm quarks produced per central PbPb collision at √ s NN = p T [10]. Charmonium production is also affected by “cold nu-clear matter” effects [10, 13, 14], such as nuclear modifications of the parton distribution func-tions. Recently, ALICE [15] and LHCb [16] observed J/ ψ suppression in pPb collisions, whilePHENIX [17] and ALICE [18] reported that the ψ (2S) is more strongly suppressed than theJ/ ψ in dAu and pPb collisions, complementing analogous observations made by fixed-targetexperiments [19].This Letter presents a measurement of the prompt ψ (2S) and J/ ψ yields (excluding productionfrom decays of b hadrons) in PbPb and pp collisions at √ s NN = µ b − and 5.4 pb − , respectively. Follow-ing related studies of the bottomonium family [20–22], the results are reported as a doubleratio, ( N ψ (2S) / N J/ ψ ) PbPb / ( N ψ (2S) / N J/ ψ ) pp , so that efficiency and acceptance corrections cancelto a large extent, reducing the systematic uncertainties. Using a previous measurement of R AA ( J/ ψ ) [6], a first measurement of R AA ( ψ (2S) ) is derived.The central feature of CMS is a superconducting solenoid of 6 m internal diameter, providinga magnetic field of 3.8 T. Within the field volume are the silicon tracker, the crystal electro-magnetic calorimeter, and the brass/scintillator hadron calorimeter. The silicon pixel and striptracker measures charged-particle trajectories in the pseudorapidity range | η | < | η | < p T is measuredwith a resolution between 1 and 2% for a typical muon in this analysis. Two steel/quartz-fibreCherenkov forward hadron (HF) calorimeters cover the range 2.9 < | η | < matched to tracks in the silicon tracker, using an algorithm optimized for the heavy-ion envi-ronment [24, 25]. In addition, an iterative track reconstruction algorithm [26] is applied to thePbPb data, limited to cone regions defined by the standalone muons. The pp reconstructionalgorithm includes an iterative tracking step in the full silicon tracker. The final parameters ofthe muon trajectory are obtained from a global fit of the standalone muon with a track in the sil-icon tracker. The single muon acceptance and identification criteria are the same as in Ref. [6].Opposite-sign muon pairs are fitted with a common vertex constraint and are kept if the fit χ probability is greater than 1%. Most of the non-prompt J/ ψ and ψ (2S) mesons, originating fromb-hadron decays, are rejected using the pseudo-proper decay length, (cid:96) ψ = L xy m ψ / p T , where L xy is the transverse distance between the µ + µ − vertex and the interaction point and m ψ is theJ/ ψ or ψ (2S) mass. The (cid:96) ψ selection condition is tuned with Monte Carlo (MC) simulation stud-ies, separately for the pp and PbPb collision systems, such that 90% of the prompt J/ ψ and ψ (2S)are kept, typically rejecting 80% of the non-prompt ones. For these studies, unpolarized promptand non-prompt J/ ψ and ψ (2S) mesons are generated with PYTHIA
EVTGEN [28], while the final-state bremsstrahlung is simulated with
PHOTOS [29]. The sig-nal events are embedded in underlying heavy-ion events, generated with
HYDJET
EANT | y | < ψ and ψ (2S) mesons are only reconstructed for p T > c , while the “forward rapidity” domain covers the range 1.6 < | y | < p T = c . Dimuons are restricted to p T <
30 GeV/ c in orderto have a well defined kinematic interval. The available PbPb data at forward rapidity couldnot be fitted reliably when split into the intervals 3 < p T < c and 6.5 < p T <
30 GeV/ c .Therefore, this analysis cannot differentiate between p T and rapidity dependent effects on themeasured double ratios. The PbPb sample is split in three bins of collision centrality, definedusing fractions of the inelastic hadronic cross section where 0% denotes the most central col-lisions: 40–100%, 20–40%, and 0–20%. This fraction is determined from the HF energy distri-bution [32]. Related variables, such as the number of nucleons participating in the collision( N part ), are evaluated using a Glauber-model calculation [33] and are only used to display thecentrality dependence of the measurements. The average N part values corresponding to thethree centrality bins above are (cid:104) N part (cid:105) = m µ + µ − ) distributions measured in central (0–20%)PbPb and pp collisions, for the midrapidity and forward rapidity bins. The results of unbinnedmaximum likelihood fits are also shown. Each charmonium resonance is described by thesum of a Gaussian function and a Crystal Ball (CB) function [34], with common mean m ,independent widths σ G and σ CB , and relative contribution of the Gaussian to the signal yield f G .In all cases, the fitted J/ ψ mean agrees within 0.3% with the world average [35]. The resolution,after averaging the Gaussian and CB widths, is about 30 MeV/ c at midrapidity and 50 MeV/ c at forward rapidity, both for pp and PbPb data. The CB radiative tail parameters α and n ,common to both charmonia, are fixed to the values obtained in fits to simulated distributions.The m , σ G , and σ CB parameters of the ψ (2S) resonance shape match the J/ ψ parameters, scaledby the ratio of their masses, m ψ (2S) / m J/ ψ [35]. This scaling assumption has been validated inanalyses of larger event samples [21, 36]. The same value for f G is used in the definition ofthe ψ (2S) and J/ ψ signal shapes. Six parameters are left free in the pp fit: m , σ G , σ CB , f G , theJ/ ψ yield, and the ψ (2S) to J/ ψ yield ratio. In the PbPb fits, instead, the double ratio replaces ) (GeV/c - m + m m ) E v en t s / ( . G e V / c = 2.76 TeV NN sCMS PbPb (a) -1 b m = 150 int L|y| < 1.6 < 30 GeV/c T ) (GeV/c - m + m m ) E v en t s / ( . G e V / c ) (GeV/c - m + m m ) E v en t s / ( . G e V / c = 2.76 TeVsCMS pp (b) -1 = 5.4 pb int L|y| < 1.6 < 30 GeV/c T ) (GeV/c - m + m m ) E v en t s / ( . G e V / c ) (GeV/c - m + m m ) E v en t s / ( . G e V / c = 2.76 TeV NN sCMS PbPb (c) -1 b m = 150 int L1.6 < |y| < 2.4 < 30 GeV/c T ) (GeV/c - m + m m ) E v en t s / ( . G e V / c ) (GeV/c - m + m m ) E v en t s / ( . G e V / c = 2.76 TeVsCMS pp (d) -1 = 5.4 pb int L1.6 < |y| < 2.4 < 30 GeV/c T ) (GeV/c - m + m m ) E v en t s / ( . G e V / c Figure 1: Dimuon invariant-mass distributions measured in central PbPb (left) and pp (right)collisions, for | y | < < p T <
30 GeV/ c (top) as well as 1.6 < | y | < < p T <
30 GeV/ c (bottom). The results of unbinned maximum likelihood fits are also shown. The ψ (2S)region is magnified in the insets.the ψ (2S) to J/ ψ ratio as one of the free parameters. In addition, given their smaller signal-to-background ratio, the PbPb data are fitted fixing the σ G / σ CB ratio to the value obtained in fitsto MC distributions.The background is described by Chebychev polynomials, of order (0 ≤ N ≤
3) determinedfor each analysis bin with log-likelihood ratio (LLR) tests. The background shape is mostlydetermined by the kinematic distributions of the muons produced in meson decays, whichare expected to change with collision centrality [6, 37, 38]. Once the background functionsare selected, the pp and three PbPb centrality samples are fitted simultaneously. Since thesignal shape does not depend on the collision centrality [6], the three PbPb centrality bins arefitted with common signal shape parameters, which are independent of the pp values; the fourbackground shapes are independent. The simultaneous fit directly provides the three doubleratios (one per centrality class), for each rapidity interval.
The systematic uncertainties from the fitting method are studied by varying the signal andbackground shapes as well as the fitted invariant-mass range. As an alternative signal shape,the sum of two CB functions with common mean and tail parameters is used, leaving allparameters free in the fit except for the mass scaling between the J/ ψ and ψ (2S) means andwidths. The uncertainty on the background is evaluated by considering three fit variations:(i) use as background shape an exponential function with a Chebychev polynomial of order1 ≤ N ≤ < m µ + µ − < c ; (iii) fit the J/ ψ and ψ (2S) regions (below 3.5 GeV/ c and above3.3 GeV/ c , respectively) with independent background functions. The maximum deviationfrom the nominal fit is added in quadrature with the signal shape uncertainty to obtain the fitsystematic uncertainty in the double ratio, which varies between 8% at midrapidity and 28%at forward rapidity. The dominant contribution to this uncertainty changes from bin to bin be-cause of the strongly varying signal-to-background ratio. A cross-check made on the centrality-integrated sample shows that counting the signal yields above a polynomial exclusively fittedto the sidebands gives a result consistent with the nominal values.Assuming no change in their polarizations, the J/ ψ and ψ (2S) acceptances are independent ofthe collision system and cancel in the double ratio. Residual effects from imperfect double-ratiocancellations of the muon reconstruction and trigger efficiency corrections have been evaluatedwith MC simulation studies. The MC double ratio of the signal efficiencies is compatible withunity. The MC statistical uncertainties, 1% at midrapidity and 5% at forward rapidity, are as-signed as the systematic uncertainties on the assumption that the efficiency corrections cancel.Differences between the MC and data distributions [6] have a negligible impact on the effi-ciency double ratio. The same charmonium p T and rapidity distributions have been used inthe generation of pp and PbPb events. The efficiency double-ratio varies by less than 1% whenchanging the kinematic distributions in PbPb within a reasonable range, evaluated using R AA measurements as a function of p T and rapidity [6].The prompt charmonia are simulated unpolarized, a scenario in good agreement with pp mea-surements [39–41]. Alternative scenarios have been considered, where the polarizations changesignificantly from the J/ ψ to the ψ (2S) and/or from pp to PbPb collisions. The impact is com-pletely negligible on the double ratio of the measurement efficiencies, while the double ratio ofthe acceptances can change by ≈ ψ and ψ (2S) yields include a residual contam-ination from b-hadron decays of up to 5%. These b-hadron contaminations are conservativelyassumed to be independent in the four yields entering the double ratio.Adding in quadrature the uncertainties mentioned above leads to total systematic uncertaintiesof 13–30%, values smaller than the corresponding statistical uncertainties.The double ratio of measured yields, ( N ψ (2S) / N J/ ψ ) PbPb / ( N ψ (2S) / N J/ ψ ) pp , is shown in Fig. 2 as afunction of centrality, for both kinematic bins. The quadratic sum of the pp statistical and sys-tematic uncertainties ( ≈ ψ (2S)signal has been observed in the midrapidity bin and an upper limit of 0.47 at 95% confidencelevel (CL) is set on the double ratio, using the Feldman–Cousins method [42].In the midrapidity bin, restricted to p T > c , the double ratio is below unity in all cen- part N pp ] y J / / N ( S ) y / [ N P b P b ] y J / / N ( S ) y [ N = 2.76 TeV NN sCMS PbPb & pp < 30 GeV/c, 1.6 < |y| < 2.4 T T Figure 2: Double ratio of measured yields, ( N ψ (2S) / N J/ ψ ) PbPb / ( N ψ (2S) / N J/ ψ ) pp , as a function ofcentrality, for the midrapidity (blue squares) and forward rapidity (red circles, slightly shifted)analysis bins. The centrality-integrated results are displayed in the right panel. Statistical (sys-tematic) uncertainties are shown as bars (boxes). The boxes at unity indicate the (global) ppuncertainties.trality bins, with a centrality-integrated value of 0.45 ± ± p T = c ,the centrality-integrated double ratio increases to 1.67 ± ± ± ± ± ψ (2S) to J/ ψ yield ratio is enhanced in central PbPb collisions with respect to pp collisions (thehypothesis of being compatible with unity has a p-value of only 0.011).Nuclear modification factors for prompt ψ (2S) production, R AA ( ψ (2S) ) , can be derived by mul-tiplying the centrality-integrated double ratios by the corresponding prompt J/ ψ R AA whichcan be found in Ref. [6]. The resulting centrality-integrated R AA values for ψ (2S) are 0.13 ± ± ± ( pp ) at midrapidity and 0.67 ± ± ± ( pp ) at forward rapidity. While the ψ (2S)/J/ ψ ratio at low p T (forward rapidity) is enhanced in cen-tral PbPb collisions, as compared to pp, the yield of ψ (2S) itself in PbPb collisions is still sup-pressed in comparison to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions.In summary, the CMS measurements reported in this Letter show two interesting observations.First, ψ (2S) production is suppressed in PbPb collisions with respect to pp collisions, in bothkinematic regions investigated. Second, in comparison to J/ ψ production and in the most cen-tral PbPb collisions, ψ (2S) production is suppressed in the range | y | < < p T <
30 GeV/ c , as expected in the sequential melting scenario and matching the corresponding bot-tomonia pattern [21], while it is enhanced in the range 1.6 < | y | < < p T <
30 GeV/ c .Such behavior implies the presence of physics processes that either cause the p T dependenceof R AA ( ψ (2S) ) to be weaker than for the R AA ( J/ ψ ) or cause the R AA ( ψ (2S) ) to start decreas-ing at higher p T . Alternatively, these processes would have to have the opposite dependence R eferences with increasing rapidity. Larger event samples are needed to evaluate in more detail how theseobservations depend separately on the p T and rapidity of the charmonium states. Acknowledgments
We congratulate our colleagues in the CERN accelerator departments for the excellent perfor-mance of the LHC and thank the technical and administrative staffs at CERN and at other CMSinstitutes for their contributions to the success of the CMS effort. In addition, we gratefullyacknowledge the computing centers and personnel of the Worldwide LHC Computing Gridfor delivering so effectively the computing infrastructure essential to our analyses. Finally, weacknowledge the enduring support for the construction and operation of the LHC and the CMSdetector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS andFWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS,MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus);MoER, ERC IUT and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA andCNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH(Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Re-public of Korea); LAS (Lithuania); MOE and UM (Malaysia); CINVESTAV, CONACYT, SEP,and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland);FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR (Russia); MESTD (Serbia);SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter,IPST, STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine);STFC (United Kingdom); DOE and NSF (USA).
References [1] F. Karsch and E. Laermann, “Thermodynamics and in-medium hadron properties fromlattice QCD”, in
Quark-Gluon Plasma III , R. C. Hwa and X.-N. Wang, eds. World ScientificPublishing Co. Pte. Ltd., 2004. arXiv:hep-lat/0305025 .[2] T. Matsui and H. Satz, “J/ ψ suppression by quark-gluon plasma formation”, Phys. Lett. B (1986) 416, doi:10.1016/0370-2693(86)91404-8 .[3] F. Karsch, D. Kharzeev, and H. Satz, “Sequential charmonium dissociation”,
Phys. Lett. B (2006) 75, doi:10.1016/j.physletb.2006.03.078 , arXiv:hep-ph/0512239 .[4] NA38 Collaboration, “ ψ (cid:48) and J/ ψ production in pW, pU and SU interactions at200 GeV/nucleon”, Phys. Lett. B (1995) 617, doi:10.1016/0370-2693(94)01614-I .[5] NA50 Collaboration, “ ψ (cid:48) production in PbPb collisions at 158 GeV/nucleon”, Eur. Phys. J.C (2007) 559, doi:10.1140/epjc/s10052-006-0153-y , arXiv:nucl-ex/0612013 .[6] CMS Collaboration, “Suppression of non-prompt J/ ψ , prompt J/ ψ , and Υ ( ) in PbPbcollisions at √ s NN = 2.76 TeV”, JHEP (2012) 063, doi:10.1007/JHEP05(2012)063 , arXiv:1201.5069 .[7] ALICE Collaboration, “J/ ψ suppression at forward rapidity in PbPb collisions at √ s NN =2.76 TeV”, Phys. Rev. Lett. (2012) 072301, doi:10.1103/PhysRevLett.109.072301 , arXiv:1202.1383 . eferences [8] ALICE Collaboration, “Centrality, rapidity and transverse momentum dependence of J/ ψ suppression in PbPb collisions at √ s NN = 2.76 TeV”, Phys. Lett. B (2013) 314, doi:10.1016/j.physletb.2014.05.064 , arXiv:1311.0214 .[9] N. Brambilla et al., “Heavy quarkonium: progress, puzzles, and opportunities”, Eur.Phys. J. C (2011) 1534, doi:10.1140/epjc/s10052-010-1534-9 , arXiv:1010.5827 .[10] X. Zhao and R. Rapp, “Medium modifications and production of charmonia at LHC”, Nucl. Phys. A (2011) 114, doi:10.1016/j.nuclphysa.2011.05.001 , arXiv:1102.2194 .[11] R. L. Thews, M. Schroedter, and J. Rafelski, “Enhanced J/ ψ production in deconfinedquark matter”, Phys. Rev. C (2001) 054905, doi:10.1103/PhysRevC.63.054905 , arXiv:hep-ph/0007323 .[12] A. Andronic, P. Braun-Munzinger, K. Redlich, and J. Stachel, “Statistical hadronization ofheavy quarks in ultra-relativistic nucleus–nucleus collisions”, Nucl. Phys. A (2007)334, doi:10.1016/j.nuclphysa.2007.02.013 , arXiv:nucl-th/0611023 .[13] R. Vogt, “Cold nuclear matter effects on J/ ψ and Υ production at energies available at theCERN Large Hadron Collider (LHC)”, Phys. Rev. C (2010) 044903, doi:10.1103/PhysRevC.81.044903 , arXiv:1003.3497 .[14] F. Arleo, “J/ ψ suppression in pA collisions from parton energy loss in cold nuclearmatter”, Nucl. Phys. A (2013) 223, doi:10.1016/j.nuclphysa.2012.12.005 .[15] ALICE Collaboration, “J/ ψ production and nuclear effects in pPb collisions at √ s NN =5.02 TeV”, JHEP (2014) 073, doi:10.1007/JHEP02(2014)073 , arXiv:1308.6726 .[16] LHCb Collaboration, “Study of J/ ψ production and cold nuclear matter effects in pPbcollisions at √ s NN = 5 TeV”, JHEP (2014) 072, doi:10.1007/JHEP02(2014)072 , arXiv:1308.6729 .[17] PHENIX Collaboration, “Nuclear modification of ψ (2S), χ c and J/ ψ production in dAucollisions at √ s NN = 200 GeV”, Phys. Rev. Lett. (2013) 202301, doi:10.1103/PhysRevLett.111.202301 , arXiv:1305.5516 .[18] ALICE Collaboration, “Suppression of ψ (2S) production in pPb collisions at √ s NN =5.02 TeV”, (2014). arXiv:1405.3796 . Submitted to Phys. Rev. Lett.[19] C. Lourenc¸o, R. Vogt, and H. K. W ¨ohri, “Energy dependence of J/ ψ absorption inproton-nucleus collisions”, JHEP (2009) 014, doi:10.1088/1126-6708/2009/02/014 , arXiv:0901.3054 .[20] CMS Collaboration, “Indications of suppression of excited Υ states in PbPb collisions at √ s NN = 2.76 TeV”, Phys. Rev. Lett. (2011) 052302, doi:10.1103/PhysRevLett.107.052302 , arXiv:1105.4894 .[21] CMS Collaboration, “Observation of sequential Υ suppression in PbPb collisions”, Phys.Rev. Lett. (2012) 222301, doi:10.1103/PhysRevLett.109.222301 , arXiv:1208.2826 . R eferences [22] CMS Collaboration, “Event activity dependence of Y(nS) production in √ s NN = 5.02 TeVpPb and √ s = 2.76 TeV pp collisions”, JHEP (2014) 103, doi:10.1007/JHEP04(2014)103 , arXiv:1312.6300 .[23] CMS Collaboration, “The CMS experiment at the CERN LHC”, JINST (2008) S08004, doi:10.1088/1748-0221/3/08/S08004 .[24] CMS Collaboration, “CMS physics technical design report: Addendum on high densityQCD with heavy ions”, J. Phys. G (2007) 2307, doi:10.1088/0954-3899/34/11/008 .[25] C. Roland, “Track reconstruction in heavy ion collisions with the CMS silicon tracker”, Nucl. Instrum. Meth. A (2006) 123, doi:10.1016/j.nima.2006.05.023 .[26] CMS Collaboration, “Description and performance of track and primary-vertexreconstruction with the CMS tracker”, (2014). arXiv:1405.6569 . Submitted to J.Instrum.[27] T. Sj ¨ostrand, S. Mrenna, and P. Z. Skands, “PYTHIA 6.4 physics and manual”,
JHEP (2006) 026, doi:10.1088/1126-6708/2006/05/026 , arXiv:hep-ph/0603175 .[28] D. J. Lange, “The EvtGen particle decay simulation package”, Nucl. Instrum. Meth. A (2001) 152, doi:10.1016/S0168-9002(01)00089-4 .[29] E. Barberio and Z. Was, “PHOTOS — A universal Monte Carlo for QED radiativecorrections: version 2.0”,
Comput. Phys. Commun. (1994) 291, doi:10.1016/0010-4655(94)90074-4 .[30] I. P. Lokhtin and A. M. Snigirev, “A model of jet quenching in ultrarelativistic heavy ioncollisions and high- p T hadron spectra at RHIC”, Eur. Phys. J. C (2006) 211, doi:10.1140/epjc/s2005-02426-3 , arXiv:hep-ph/0506189 .[31] GEANT Collaboration, “Geant4—a simulation toolkit”, Nucl. Instrum. Meth. A (2003) 250, doi:10.1016/S0168-9002(03)01368-8 .[32] CMS Collaboration, “Dependence on pseudorapidity and centrality of charged hadronproduction in PbPb collisions at √ s NN = 2.76 TeV”, JHEP (2011) 141, doi:10.1007/JHEP08(2011)141 , arXiv:1107.4800 .[33] CMS Collaboration, “Observation and studies of jet quenching in PbPb collisions at √ s NN = 2.76 TeV”, Phys. Rev. C (2011) 024906, doi:10.1103/PhysRevC.84.024906 , arXiv:1102.1957 .[34] M. J. Oreglia, “A study of the reactions ψ (cid:48) → γγψ ”. PhD thesis, Stanford University,1980. SLAC Report SLAC-R-236.[35] Particle Data Group, K. A. Olive et al., “Review of Particle Physics”, Chin. Phys. C (2014) 090001, doi:10.1088/1674-1137/38/9/090001 .[36] CMS Collaboration, “J/ ψ and ψ (2S) production in pp collisions at √ s = 7 TeV”, JHEP (2012) 011, doi:10.1007/JHEP02(2012)011 , arXiv:1111.1557 .[37] CMS Collaboration, “Study of high- p T charged particle suppression in PbPb compared topp collisions at √ s NN = 2.76 TeV”, Eur. Phys. J. C (2012) 1945, doi:10.1140/epjc/s10052-012-1945-x , arXiv:1202.2554 . eferences [38] ALICE Collaboration, “Suppression of high transverse momentum D mesons in centralPbPb collisions at √ s NN = 2.76 TeV”, JHEP (2012) 112, doi:10.1007/JHEP09(2012)112 , arXiv:1203.2160 .[39] ALICE Collaboration, “J/ ψ polarization in pp collisions at √ s = 7 TeV”, Phys. Rev. Lett. (2011) 082001, doi:10.1103/PhysRevLett.108.082001 , arXiv:1111.1630 .[40] CMS Collaboration, “Measurement of the prompt J/ ψ and ψ (2S) polarizations in ppcollisions at √ s = 7 TeV”, Phys. Lett. B (2013) 381, doi:10.1016/j.physletb.2013.10.055 , arXiv:1307.6070 .[41] LHCb Collaboration, “Measurement of J/ ψ polarization in pp collisions at √ s = 7 TeV”, Eur. Phys. J. C (2013) 2631, doi:10.1140/epjc/s10052-013-2631-3 , arXiv:1307.6379 .[42] G. J. Feldman and R. D. Cousins, “Unified approach to the classical statistical analysis ofsmall signals”, Phys. Rev. D (1998) 3873, doi:10.1103/PhysRevD.57.3873 , arXiv:physics/9711021 . R eferences A The CMS Collaboration
Yerevan Physics Institute, Yerevan, Armenia
V. Khachatryan, A.M. Sirunyan, A. Tumasyan
Institut f ¨ur Hochenergiephysik der OeAW, Wien, Austria
W. Adam, T. Bergauer, M. Dragicevic, J. Er ¨o, C. Fabjan , M. Friedl, R. Fr ¨uhwirth , V.M. Ghete,C. Hartl, N. H ¨ormann, J. Hrubec, M. Jeitler , W. Kiesenhofer, V. Kn ¨unz, M. Krammer ,I. Kr¨atschmer, D. Liko, I. Mikulec, D. Rabady , B. Rahbaran, H. Rohringer, R. Sch ¨ofbeck,J. Strauss, A. Taurok, W. Treberer-Treberspurg, W. Waltenberger, C.-E. Wulz National Centre for Particle and High Energy Physics, Minsk, Belarus
V. Mossolov, N. Shumeiko, J. Suarez Gonzalez
Universiteit Antwerpen, Antwerpen, Belgium
S. Alderweireldt, M. Bansal, S. Bansal, T. Cornelis, E.A. De Wolf, X. Janssen, A. Knutsson,S. Luyckx, S. Ochesanu, B. Roland, R. Rougny, M. Van De Klundert, H. Van Haevermaet, P. VanMechelen, N. Van Remortel, A. Van Spilbeeck
Vrije Universiteit Brussel, Brussel, Belgium
F. Blekman, S. Blyweert, J. D’Hondt, N. Daci, N. Heracleous, J. Keaveney, S. Lowette, M. Maes,A. Olbrechts, Q. Python, D. Strom, S. Tavernier, W. Van Doninck, P. Van Mulders, G.P. VanOnsem, I. Villella
Universit´e Libre de Bruxelles, Bruxelles, Belgium
C. Caillol, B. Clerbaux, G. De Lentdecker, D. Dobur, L. Favart, A.P.R. Gay, A. Grebenyuk,A. L´eonard, A. Mohammadi, L. Perni`e , T. Reis, T. Seva, L. Thomas, C. Vander Velde, P. Vanlaer,J. Wang Ghent University, Ghent, Belgium
V. Adler, K. Beernaert, L. Benucci, A. Cimmino, S. Costantini, S. Crucy, S. Dildick, A. Fagot,G. Garcia, J. Mccartin, A.A. Ocampo Rios, D. Ryckbosch, S. Salva Diblen, M. Sigamani,N. Strobbe, F. Thyssen, M. Tytgat, E. Yazgan, N. Zaganidis
Universit´e Catholique de Louvain, Louvain-la-Neuve, Belgium
S. Basegmez, C. Beluffi , G. Bruno, R. Castello, A. Caudron, L. Ceard, G.G. Da Silveira,C. Delaere, T. du Pree, D. Favart, L. Forthomme, A. Giammanco , J. Hollar, P. Jez, M. Komm,V. Lemaitre, C. Nuttens, D. Pagano, L. Perrini, A. Pin, K. Piotrzkowski, A. Popov ,L. Quertenmont, M. Selvaggi, M. Vidal Marono, J.M. Vizan Garcia Universit´e de Mons, Mons, Belgium
N. Beliy, T. Caebergs, E. Daubie, G.H. Hammad
Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil
W.L. Ald´a J ´unior, G.A. Alves, L. Brito, M. Correa Martins Junior, T. Dos Reis Martins, C. MoraHerrera, M.E. Pol
Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
W. Carvalho, J. Chinellato , A. Cust ´odio, E.M. Da Costa, D. De Jesus Damiao, C. De OliveiraMartins, S. Fonseca De Souza, H. Malbouisson, D. Matos Figueiredo, L. Mundim, H. Nogima,W.L. Prado Da Silva, J. Santaolalla, A. Santoro, A. Sznajder, E.J. Tonelli Manganote , A. VilelaPereira A The CMS Collaboration
Universidade Estadual Paulista a , Universidade Federal do ABC b , S˜ao Paulo, Brazil C.A. Bernardes b , S. Dogra a , T.R. Fernandez Perez Tomei a , E.M. Gregores b , P.G. Mercadante b ,S.F. Novaes a , Sandra S. Padula a Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
A. Aleksandrov, V. Genchev , P. Iaydjiev, A. Marinov, S. Piperov, M. Rodozov, S. Stoykova,G. Sultanov, V. Tcholakov, M. Vutova University of Sofia, Sofia, Bulgaria
A. Dimitrov, I. Glushkov, R. Hadjiiska, V. Kozhuharov, L. Litov, B. Pavlov, P. Petkov
Institute of High Energy Physics, Beijing, China
J.G. Bian, G.M. Chen, H.S. Chen, M. Chen, R. Du, C.H. Jiang, S. Liang, R. Plestina , J. Tao,X. Wang, Z. Wang State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China
C. Asawatangtrakuldee, Y. Ban, Y. Guo, Q. Li, W. Li, S. Liu, Y. Mao, S.J. Qian, D. Wang, L. Zhang,W. Zou
Universidad de Los Andes, Bogota, Colombia
C. Avila, L.F. Chaparro Sierra, C. Florez, J.P. Gomez, B. Gomez Moreno, J.C. Sanabria
University of Split, Faculty of Electrical Engineering, Mechanical Engineering and NavalArchitecture, Split, Croatia
N. Godinovic, D. Lelas, D. Polic, I. Puljak
University of Split, Faculty of Science, Split, Croatia
Z. Antunovic, M. Kovac
Institute Rudjer Boskovic, Zagreb, Croatia
V. Brigljevic, K. Kadija, J. Luetic, D. Mekterovic, L. Sudic
University of Cyprus, Nicosia, Cyprus
A. Attikis, G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis
Charles University, Prague, Czech Republic
M. Bodlak, M. Finger, M. Finger Jr. Academy of Scientific Research and Technology of the Arab Republic of Egypt, EgyptianNetwork of High Energy Physics, Cairo, Egypt
Y. Assran , A. Ellithi Kamel , M.A. Mahmoud , A. Radi National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
M. Kadastik, M. Murumaa, M. Raidal, A. Tiko
Department of Physics, University of Helsinki, Helsinki, Finland
P. Eerola, G. Fedi, M. Voutilainen
Helsinki Institute of Physics, Helsinki, Finland
J. H¨ark ¨onen, V. Karim¨aki, R. Kinnunen, M.J. Kortelainen, T. Lamp´en, K. Lassila-Perini, S. Lehti,T. Lind´en, P. Luukka, T. M¨aenp¨a¨a, T. Peltola, E. Tuominen, J. Tuominiemi, E. Tuovinen,L. Wendland
Lappeenranta University of Technology, Lappeenranta, Finland
T. Tuuva DSM/IRFU, CEA/Saclay, Gif-sur-Yvette, France
M. Besancon, F. Couderc, M. Dejardin, D. Denegri, B. Fabbro, J.L. Faure, C. Favaro, F. Ferri,S. Ganjour, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, E. Locci, J. Malcles,J. Rander, A. Rosowsky, M. Titov
Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
S. Baffioni, F. Beaudette, P. Busson, C. Charlot, T. Dahms, M. Dalchenko, L. Dobrzynski,N. Filipovic, A. Florent, R. Granier de Cassagnac, L. Mastrolorenzo, P. Min´e, C. Mironov,I.N. Naranjo, M. Nguyen, C. Ochando, P. Paganini, S. Regnard, R. Salerno, J.B. Sauvan, Y. Sirois,C. Veelken, Y. Yilmaz, A. Zabi
Institut Pluridisciplinaire Hubert Curien, Universit´e de Strasbourg, Universit´e de HauteAlsace Mulhouse, CNRS/IN2P3, Strasbourg, France
J.-L. Agram , J. Andrea, A. Aubin, D. Bloch, J.-M. Brom, E.C. Chabert, C. Collard, E. Conte ,J.-C. Fontaine , D. Gel´e, U. Goerlach, C. Goetzmann, A.-C. Le Bihan, P. Van Hove Centre de Calcul de l’Institut National de Physique Nucleaire et de Physique des Particules,CNRS/IN2P3, Villeurbanne, France
S. Gadrat
Universit´e de Lyon, Universit´e Claude Bernard Lyon 1, CNRS-IN2P3, Institut de PhysiqueNucl´eaire de Lyon, Villeurbanne, France
S. Beauceron, N. Beaupere, G. Boudoul , E. Bouvier, S. Brochet, C.A. Carrillo Montoya,J. Chasserat, R. Chierici, D. Contardo , P. Depasse, H. El Mamouni, J. Fan, J. Fay, S. Gascon,M. Gouzevitch, B. Ille, T. Kurca, M. Lethuillier, L. Mirabito, S. Perries, J.D. Ruiz Alvarez,D. Sabes, L. Sgandurra, V. Sordini, M. Vander Donckt, P. Verdier, S. Viret, H. Xiao Institute of High Energy Physics and Informatization, Tbilisi State University, Tbilisi,Georgia
Z. Tsamalaidze RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany
C. Autermann, S. Beranek, M. Bontenackels, M. Edelhoff, L. Feld, O. Hindrichs, K. Klein,A. Ostapchuk, A. Perieanu, F. Raupach, J. Sammet, S. Schael, H. Weber, B. Wittmer, V. Zhukov RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany
M. Ata, E. Dietz-Laursonn, D. Duchardt, M. Erdmann, R. Fischer, A. G ¨uth, T. Hebbeker,C. Heidemann, K. Hoepfner, D. Klingebiel, S. Knutzen, P. Kreuzer, M. Merschmeyer, A. Meyer,P. Millet, M. Olschewski, K. Padeken, P. Papacz, H. Reithler, S.A. Schmitz, L. Sonnenschein,D. Teyssier, S. Th ¨uer, M. Weber
RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany
V. Cherepanov, Y. Erdogan, G. Fl ¨ugge, H. Geenen, M. Geisler, W. Haj Ahmad, A. Heister,F. Hoehle, B. Kargoll, T. Kress, Y. Kuessel, J. Lingemann , A. Nowack, I.M. Nugent, L. Perchalla,O. Pooth, A. Stahl Deutsches Elektronen-Synchrotron, Hamburg, Germany
I. Asin, N. Bartosik, J. Behr, W. Behrenhoff, U. Behrens, A.J. Bell, M. Bergholz , A. Bethani,K. Borras, A. Burgmeier, A. Cakir, L. Calligaris, A. Campbell, S. Choudhury, F. Costanza,C. Diez Pardos, S. Dooling, T. Dorland, G. Eckerlin, D. Eckstein, T. Eichhorn, G. Flucke, J. GarayGarcia, A. Geiser, P. Gunnellini, J. Hauk, M. Hempel, D. Horton, H. Jung, A. Kalogeropoulos,M. Kasemann, P. Katsas, J. Kieseler, C. Kleinwort, D. Kr ¨ucker, W. Lange, J. Leonard, K. Lipka,A. Lobanov, W. Lohmann , B. Lutz, R. Mankel, I. Marfin, I.-A. Melzer-Pellmann, A.B. Meyer,G. Mittag, J. Mnich, A. Mussgiller, S. Naumann-Emme, A. Nayak, O. Novgorodova, F. Nowak, A The CMS Collaboration
E. Ntomari, H. Perrey, D. Pitzl, R. Placakyte, A. Raspereza, P.M. Ribeiro Cipriano, E. Ron,M. ¨O. Sahin, J. Salfeld-Nebgen, P. Saxena, R. Schmidt , T. Schoerner-Sadenius, M. Schr ¨oder,C. Seitz, S. Spannagel, A.D.R. Vargas Trevino, R. Walsh, C. Wissing University of Hamburg, Hamburg, Germany
M. Aldaya Martin, V. Blobel, M. Centis Vignali, A.R. Draeger, J. Erfle, E. Garutti, K. Goebel,M. G ¨orner, J. Haller, M. Hoffmann, R.S. H ¨oing, H. Kirschenmann, R. Klanner, R. Kogler,J. Lange, T. Lapsien, T. Lenz, I. Marchesini, J. Ott, T. Peiffer, N. Pietsch, J. Poehlsen, T. Poehlsen,D. Rathjens, C. Sander, H. Schettler, P. Schleper, E. Schlieckau, A. Schmidt, M. Seidel, V. Sola,H. Stadie, G. Steinbr ¨uck, D. Troendle, E. Usai, L. Vanelderen
Institut f ¨ur Experimentelle Kernphysik, Karlsruhe, Germany
C. Barth, C. Baus, J. Berger, C. B ¨oser, E. Butz, T. Chwalek, W. De Boer, A. Descroix, A. Dierlamm,M. Feindt, F. Frensch, M. Giffels, F. Hartmann , T. Hauth , U. Husemann, I. Katkov ,A. Kornmayer , E. Kuznetsova, P. Lobelle Pardo, M.U. Mozer, Th. M ¨uller, A. N ¨urnberg,G. Quast, K. Rabbertz, F. Ratnikov, S. R ¨ocker, H.J. Simonis, F.M. Stober, R. Ulrich, J. Wagner-Kuhr, S. Wayand, T. Weiler, R. Wolf Institute of Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi,Greece
G. Anagnostou, G. Daskalakis, T. Geralis, V.A. Giakoumopoulou, A. Kyriakis, D. Loukas,A. Markou, C. Markou, A. Psallidas, I. Topsis-Giotis
University of Athens, Athens, Greece
A. Agapitos, S. Kesisoglou, A. Panagiotou, N. Saoulidou, E. Stiliaris
University of Io´annina, Io´annina, Greece
X. Aslanoglou, I. Evangelou, G. Flouris, C. Foudas, P. Kokkas, N. Manthos, I. Papadopoulos,E. Paradas
Wigner Research Centre for Physics, Budapest, Hungary
G. Bencze, C. Hajdu, P. Hidas, D. Horvath , F. Sikler, V. Veszpremi, G. Vesztergombi ,A.J. Zsigmond Institute of Nuclear Research ATOMKI, Debrecen, Hungary
N. Beni, S. Czellar, J. Karancsi , J. Molnar, J. Palinkas, Z. Szillasi University of Debrecen, Debrecen, Hungary
P. Raics, Z.L. Trocsanyi, B. Ujvari
National Institute of Science Education and Research, Bhubaneswar, India
S.K. Swain
Panjab University, Chandigarh, India
S.B. Beri, V. Bhatnagar, R. Gupta, U.Bhawandeep, A.K. Kalsi, M. Kaur, M. Mittal, N. Nishu,J.B. Singh
University of Delhi, Delhi, India
Ashok Kumar, Arun Kumar, S. Ahuja, A. Bhardwaj, B.C. Choudhary, A. Kumar, S. Malhotra,M. Naimuddin, K. Ranjan, V. Sharma
Saha Institute of Nuclear Physics, Kolkata, India
S. Banerjee, S. Bhattacharya, K. Chatterjee, S. Dutta, B. Gomber, Sa. Jain, Sh. Jain, R. Khurana,A. Modak, S. Mukherjee, D. Roy, S. Sarkar, M. Sharan5
S. Banerjee, S. Bhattacharya, K. Chatterjee, S. Dutta, B. Gomber, Sa. Jain, Sh. Jain, R. Khurana,A. Modak, S. Mukherjee, D. Roy, S. Sarkar, M. Sharan5 Bhabha Atomic Research Centre, Mumbai, India
A. Abdulsalam, D. Dutta, S. Kailas, V. Kumar, A.K. Mohanty , L.M. Pant, P. Shukla, A. Topkar Tata Institute of Fundamental Research, Mumbai, India
T. Aziz, S. Banerjee, S. Bhowmik , R.M. Chatterjee, R.K. Dewanjee, S. Dugad, S. Ganguly,S. Ghosh, M. Guchait, A. Gurtu , G. Kole, S. Kumar, M. Maity , G. Majumder, K. Mazumdar,G.B. Mohanty, B. Parida, K. Sudhakar, N. Wickramage Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
H. Bakhshiansohi, H. Behnamian, S.M. Etesami , A. Fahim , R. Goldouzian, A. Jafari,M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi, F. RezaeiHosseinabadi, B. Safarzadeh , M. Zeinali University College Dublin, Dublin, Ireland
M. Felcini, M. Grunewald
INFN Sezione di Bari a , Universit`a di Bari b , Politecnico di Bari c , Bari, Italy M. Abbrescia a , b , L. Barbone a , b , C. Calabria a , b , S.S. Chhibra a , b , A. Colaleo a , D. Creanza a , c , N. DeFilippis a , c , M. De Palma a , b , L. Fiore a , G. Iaselli a , c , G. Maggi a , c , M. Maggi a , S. My a , c , S. Nuzzo a , b ,A. Pompili a , b , G. Pugliese a , c , R. Radogna a , b ,2 , G. Selvaggi a , b , L. Silvestris a ,2 , G. Singh a , b ,R. Venditti a , b , P. Verwilligen a , G. Zito a INFN Sezione di Bologna a , Universit`a di Bologna b , Bologna, Italy G. Abbiendi a , A.C. Benvenuti a , D. Bonacorsi a , b , S. Braibant-Giacomelli a , b , L. Brigliadori a , b ,R. Campanini a , b , P. Capiluppi a , b , A. Castro a , b , F.R. Cavallo a , G. Codispoti a , b , M. Cuffiani a , b ,G.M. Dallavalle a , F. Fabbri a , A. Fanfani a , b , D. Fasanella a , b , P. Giacomelli a , C. Grandi a ,L. Guiducci a , b , S. Marcellini a , G. Masetti a ,2 , A. Montanari a , F.L. Navarria a , b , A. Perrotta a ,F. Primavera a , b , A.M. Rossi a , b , T. Rovelli a , b , G.P. Siroli a , b , N. Tosi a , b , R. Travaglini a , b INFN Sezione di Catania a , Universit`a di Catania b , CSFNSM c , Catania, Italy S. Albergo a , b , G. Cappello a , M. Chiorboli a , b , S. Costa a , b , F. Giordano a ,2 , R. Potenza a , b ,A. Tricomi a , b , C. Tuve a , b INFN Sezione di Firenze a , Universit`a di Firenze b , Firenze, Italy G. Barbagli a , V. Ciulli a , b , C. Civinini a , R. D’Alessandro a , b , E. Focardi a , b , E. Gallo a , S. Gonzi a , b ,V. Gori a , b ,2 , P. Lenzi a , b , M. Meschini a , S. Paoletti a , G. Sguazzoni a , A. Tropiano a , b INFN Laboratori Nazionali di Frascati, Frascati, Italy
L. Benussi, S. Bianco, F. Fabbri, D. Piccolo
INFN Sezione di Genova a , Universit`a di Genova b , Genova, Italy F. Ferro a , M. Lo Vetere a , b , E. Robutti a , S. Tosi a , b INFN Sezione di Milano-Bicocca a , Universit`a di Milano-Bicocca b , Milano, Italy M.E. Dinardo a , b , S. Fiorendi a , b ,2 , S. Gennai a ,2 , R. Gerosa a , b ,2 , A. Ghezzi a , b , P. Govoni a , b ,M.T. Lucchini a , b ,2 , S. Malvezzi a , R.A. Manzoni a , b , A. Martelli a , b , B. Marzocchi a , b , D. Menasce a ,L. Moroni a , M. Paganoni a , b , D. Pedrini a , S. Ragazzi a , b , N. Redaelli a , T. Tabarelli de Fatis a , b INFN Sezione di Napoli a , Universit`a di Napoli ’Federico II’ b , Universit`a dellaBasilicata (Potenza) c , Universit`a G. Marconi (Roma) d , Napoli, Italy S. Buontempo a , N. Cavallo a , c , S. Di Guida a , d ,2 , F. Fabozzi a , c , A.O.M. Iorio a , b , L. Lista a ,S. Meola a , d ,2 , M. Merola a , P. Paolucci a ,2 A The CMS Collaboration
INFN Sezione di Padova a , Universit`a di Padova b , Universit`a di Trento (Trento) c , Padova,Italy M. Bellato a , M. Biasotto a ,25 , D. Bisello a , b , A. Branca a , b , R. Carlin a , b , P. Checchia a ,M. Dall’Osso a , b , T. Dorigo a , F. Fanzago a , M. Galanti a , b , F. Gasparini a , b , U. Gasparini a , b ,A. Gozzelino a , K. Kanishchev a , c , S. Lacaprara a , M. Margoni a , b , A.T. Meneguzzo a , b , J. Pazzini a , b ,N. Pozzobon a , b , P. Ronchese a , b , F. Simonetto a , b , E. Torassa a , M. Tosi a , b , A. Triossi a , S. Ventura a ,A. Zucchetta a , b , G. Zumerle a , b INFN Sezione di Pavia a , Universit`a di Pavia b , Pavia, Italy M. Gabusi a , b , S.P. Ratti a , b , C. Riccardi a , b , P. Salvini a , P. Vitulo a , b INFN Sezione di Perugia a , Universit`a di Perugia b , Perugia, Italy M. Biasini a , b , G.M. Bilei a , D. Ciangottini a , b , L. Fan `o a , b , P. Lariccia a , b , G. Mantovani a , b ,M. Menichelli a , F. Romeo a , b , A. Saha a , A. Santocchia a , b , A. Spiezia a , b ,2 INFN Sezione di Pisa a , Universit`a di Pisa b , Scuola Normale Superiore di Pisa c , Pisa, Italy K. Androsov a ,26 , P. Azzurri a , G. Bagliesi a , J. Bernardini a , T. Boccali a , G. Broccolo a , c , R. Castaldi a ,M.A. Ciocci a ,26 , R. Dell’Orso a , S. Donato a , c , F. Fiori a , c , L. Fo`a a , c , A. Giassi a , M.T. Grippo a ,26 ,F. Ligabue a , c , T. Lomtadze a , L. Martini a , b , A. Messineo a , b , C.S. Moon a ,27 , F. Palla a ,2 , A. Rizzi a , b ,A. Savoy-Navarro a ,28 , A.T. Serban a , P. Spagnolo a , P. Squillacioti a ,26 , R. Tenchini a , G. Tonelli a , b ,A. Venturi a , P.G. Verdini a , C. Vernieri a , c ,2 INFN Sezione di Roma a , Universit`a di Roma b , Roma, Italy L. Barone a , b , F. Cavallari a , G. D’imperio a , b , D. Del Re a , b , M. Diemoz a , M. Grassi a , b , C. Jorda a ,E. Longo a , b , F. Margaroli a , b , P. Meridiani a , F. Micheli a , b ,2 , S. Nourbakhsh a , b , G. Organtini a , b ,R. Paramatti a , S. Rahatlou a , b , C. Rovelli a , F. Santanastasio a , b , L. Soffi a , b ,2 , P. Traczyk a , b INFN Sezione di Torino a , Universit`a di Torino b , Universit`a del Piemonte Orientale (No-vara) c , Torino, Italy N. Amapane a , b , R. Arcidiacono a , c , S. Argiro a , b ,2 , M. Arneodo a , c , R. Bellan a , b , C. Biino a ,N. Cartiglia a , S. Casasso a , b ,2 , M. Costa a , b , A. Degano a , b , N. Demaria a , L. Finco a , b , C. Mariotti a ,S. Maselli a , E. Migliore a , b , V. Monaco a , b , M. Musich a , M.M. Obertino a , c ,2 , G. Ortona a , b ,L. Pacher a , b , N. Pastrone a , M. Pelliccioni a , G.L. Pinna Angioni a , b , A. Potenza a , b , A. Romero a , b ,M. Ruspa a , c , R. Sacchi a , b , A. Solano a , b , A. Staiano a , U. Tamponi a INFN Sezione di Trieste a , Universit`a di Trieste b , Trieste, Italy S. Belforte a , V. Candelise a , b , M. Casarsa a , F. Cossutti a , G. Della Ricca a , b , B. Gobbo a , C. LaLicata a , b , M. Marone a , b , D. Montanino a , b , A. Schizzi a , b ,2 , T. Umer a , b , A. Zanetti a Kangwon National University, Chunchon, Korea
S. Chang, A. Kropivnitskaya, S.K. Nam
Kyungpook National University, Daegu, Korea
D.H. Kim, G.N. Kim, M.S. Kim, D.J. Kong, S. Lee, Y.D. Oh, H. Park, A. Sakharov, D.C. Son
Chonbuk National University, Jeonju, Korea
T.J. Kim
Chonnam National University, Institute for Universe and Elementary Particles, Kwangju,Korea
J.Y. Kim, S. Song
Korea University, Seoul, Korea
S. Choi, D. Gyun, B. Hong, M. Jo, H. Kim, Y. Kim, B. Lee, K.S. Lee, S.K. Park, Y. Roh University of Seoul, Seoul, Korea
M. Choi, J.H. Kim, I.C. Park, S. Park, G. Ryu, M.S. Ryu
Sungkyunkwan University, Suwon, Korea
Y. Choi, Y.K. Choi, J. Goh, D. Kim, E. Kwon, J. Lee, H. Seo, I. Yu
Vilnius University, Vilnius, Lithuania
A. Juodagalvis
National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia
J.R. Komaragiri, M.A.B. Md Ali
Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico
H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-de La Cruz , R. Lopez-Fernandez,A. Sanchez-Hernandez Universidad Iberoamericana, Mexico City, Mexico
S. Carrillo Moreno, F. Vazquez Valencia
Benemerita Universidad Autonoma de Puebla, Puebla, Mexico
I. Pedraza, H.A. Salazar Ibarguen
Universidad Aut ´onoma de San Luis Potos´ı, San Luis Potos´ı, Mexico
E. Casimiro Linares, A. Morelos Pineda
University of Auckland, Auckland, New Zealand
D. Krofcheck
University of Canterbury, Christchurch, New Zealand
P.H. Butler, S. Reucroft
National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan
A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, S. Khalid, W.A. Khan, T. Khurshid,M.A. Shah, M. Shoaib
National Centre for Nuclear Research, Swierk, Poland
H. Bialkowska, M. Bluj, B. Boimska, T. Frueboes, M. G ´orski, M. Kazana, K. Nawrocki,K. Romanowska-Rybinska, M. Szleper, P. Zalewski
Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
G. Brona, K. Bunkowski, M. Cwiok, W. Dominik, K. Doroba, A. Kalinowski, M. Konecki,J. Krolikowski, M. Misiura, M. Olszewski, W. Wolszczak
Laborat ´orio de Instrumenta¸c˜ao e F´ısica Experimental de Part´ıculas, Lisboa, Portugal
P. Bargassa, C. Beir˜ao Da Cruz E Silva, P. Faccioli, P.G. Ferreira Parracho, M. Gallinaro,F. Nguyen, J. Rodrigues Antunes, J. Seixas, J. Varela, P. Vischia
Joint Institute for Nuclear Research, Dubna, Russia
S. Afanasiev, I. Golutvin, V. Karjavin, V. Konoplyanikov, V. Korenkov, G. Kozlov, A. Lanev,A. Malakhov, V. Matveev , V.V. Mitsyn, P. Moisenz, V. Palichik, V. Perelygin, S. Shmatov,N. Skatchkov, V. Smirnov, E. Tikhonenko, A. Zarubin Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg), Russia
V. Golovtsov, Y. Ivanov, V. Kim , P. Levchenko, V. Murzin, V. Oreshkin, I. Smirnov, V. Sulimov,L. Uvarov, S. Vavilov, A. Vorobyev, An. Vorobyev A The CMS Collaboration
Institute for Nuclear Research, Moscow, Russia
Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, M. Kirsanov, N. Krasnikov, A. Pashenkov,D. Tlisov, A. Toropin
Institute for Theoretical and Experimental Physics, Moscow, Russia
V. Epshteyn, V. Gavrilov, N. Lychkovskaya, V. Popov, G. Safronov, S. Semenov, A. Spiridonov,V. Stolin, E. Vlasov, A. Zhokin
P.N. Lebedev Physical Institute, Moscow, Russia
V. Andreev, M. Azarkin, I. Dremin, M. Kirakosyan, A. Leonidov, G. Mesyats, S.V. Rusakov,A. Vinogradov
Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow,Russia
A. Belyaev, E. Boos, A. Ershov, A. Gribushin, A. Kaminskiy , O. Kodolova, V. Korotkikh,I. Lokhtin, S. Obraztsov, S. Petrushanko, V. Savrin, A. Snigirev, I. Vardanyan State Research Center of Russian Federation, Institute for High Energy Physics, Protvino,Russia
I. Azhgirey, I. Bayshev, S. Bitioukov, V. Kachanov, A. Kalinin, D. Konstantinov, V. Krychkine,V. Petrov, R. Ryutin, A. Sobol, L. Tourtchanovitch, S. Troshin, N. Tyurin, A. Uzunian, A. Volkov
University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, Belgrade,Serbia
P. Adzic , M. Ekmedzic, J. Milosevic, V. Rekovic Centro de Investigaciones Energ´eticas Medioambientales y Tecnol ´ogicas (CIEMAT),Madrid, Spain
J. Alcaraz Maestre, C. Battilana, E. Calvo, M. Cerrada, M. Chamizo Llatas, N. Colino, B. De LaCruz, A. Delgado Peris, D. Dom´ınguez V´azquez, A. Escalante Del Valle, C. Fernandez Bedoya,J.P. Fern´andez Ramos, J. Flix, M.C. Fouz, P. Garcia-Abia, O. Gonzalez Lopez, S. Goy Lopez,J.M. Hernandez, M.I. Josa, G. Merino, E. Navarro De Martino, A. P´erez-Calero Yzquierdo,J. Puerta Pelayo, A. Quintario Olmeda, I. Redondo, L. Romero, M.S. Soares
Universidad Aut ´onoma de Madrid, Madrid, Spain
C. Albajar, J.F. de Troc ´oniz, M. Missiroli, D. Moran
Universidad de Oviedo, Oviedo, Spain
H. Brun, J. Cuevas, J. Fernandez Menendez, S. Folgueras, I. Gonzalez Caballero, L. LloretIglesias
Instituto de F´ısica de Cantabria (IFCA), CSIC-Universidad de Cantabria, Santander, Spain
J.A. Brochero Cifuentes, I.J. Cabrillo, A. Calderon, J. Duarte Campderros, M. Fernandez,G. Gomez, A. Graziano, A. Lopez Virto, J. Marco, R. Marco, C. Martinez Rivero, F. Matorras,F.J. Munoz Sanchez, J. Piedra Gomez, T. Rodrigo, A.Y. Rodr´ıguez-Marrero, A. Ruiz-Jimeno,L. Scodellaro, I. Vila, R. Vilar Cortabitarte
CERN, European Organization for Nuclear Research, Geneva, Switzerland
D. Abbaneo, E. Auffray, G. Auzinger, M. Bachtis, P. Baillon, A.H. Ball, D. Barney, A. Benaglia,J. Bendavid, L. Benhabib, J.F. Benitez, C. Bernet , G. Bianchi, P. Bloch, A. Bocci, A. Bonato,O. Bondu, C. Botta, H. Breuker, T. Camporesi, G. Cerminara, S. Colafranceschi , M. D’Alfonso,D. d’Enterria, A. Dabrowski, A. David, F. De Guio, A. De Roeck, S. De Visscher, M. Dobson,M. Dordevic, N. Dupont-Sagorin, A. Elliott-Peisert, J. Eugster, G. Franzoni, W. Funk, D. Gigi,K. Gill, D. Giordano, M. Girone, F. Glege, R. Guida, S. Gundacker, M. Guthoff, J. Hammer, M. Hansen, P. Harris, J. Hegeman, V. Innocente, P. Janot, K. Kousouris, K. Krajczar, P. Lecoq,C. Lourenc¸o, N. Magini, L. Malgeri, M. Mannelli, J. Marrouche, L. Masetti, F. Meijers, S. Mersi,E. Meschi, F. Moortgat, S. Morovic, M. Mulders, P. Musella, L. Orsini, L. Pape, E. Perez,L. Perrozzi, A. Petrilli, G. Petrucciani, A. Pfeiffer, M. Pierini, M. Pimi¨a, D. Piparo, M. Plagge,A. Racz, G. Rolandi , M. Rovere, H. Sakulin, C. Sch¨afer, C. Schwick, A. Sharma, P. Siegrist,P. Silva, M. Simon, P. Sphicas , D. Spiga, J. Steggemann, B. Stieger, M. Stoye, Y. Takahashi,D. Treille, A. Tsirou, G.I. Veres , J.R. Vlimant, N. Wardle, H.K. W ¨ohri, H. Wollny, W.D. Zeuner Paul Scherrer Institut, Villigen, Switzerland
W. Bertl, K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski,U. Langenegger, D. Renker, T. Rohe
Institute for Particle Physics, ETH Zurich, Zurich, Switzerland
F. Bachmair, L. B¨ani, L. Bianchini, P. Bortignon, M.A. Buchmann, B. Casal, N. Chanon,A. Deisher, G. Dissertori, M. Dittmar, M. Doneg`a, M. D ¨unser, P. Eller, C. Grab, D. Hits,W. Lustermann, B. Mangano, A.C. Marini, P. Martinez Ruiz del Arbol, D. Meister, N. Mohr,C. N¨ageli , F. Nessi-Tedaldi, F. Pandolfi, F. Pauss, M. Peruzzi, M. Quittnat, L. Rebane,M. Rossini, A. Starodumov , M. Takahashi, K. Theofilatos, R. Wallny, H.A. Weber Universit¨at Z ¨urich, Zurich, Switzerland
C. Amsler , M.F. Canelli, V. Chiochia, A. De Cosa, A. Hinzmann, T. Hreus, B. Kilminster,C. Lange, B. Millan Mejias, J. Ngadiuba, P. Robmann, F.J. Ronga, S. Taroni, M. Verzetti, Y. Yang National Central University, Chung-Li, Taiwan
M. Cardaci, K.H. Chen, C. Ferro, C.M. Kuo, W. Lin, Y.J. Lu, R. Volpe, S.S. Yu
National Taiwan University (NTU), Taipei, Taiwan
P. Chang, Y.H. Chang, Y.W. Chang, Y. Chao, K.F. Chen, P.H. Chen, C. Dietz, U. Grundler, W.-S. Hou, K.Y. Kao, Y.J. Lei, Y.F. Liu, R.-S. Lu, D. Majumder, E. Petrakou, Y.M. Tzeng, R. Wilken
Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, Thailand
B. Asavapibhop, N. Srimanobhas, N. Suwonjandee
Cukurova University, Adana, Turkey
A. Adiguzel, M.N. Bakirci , S. Cerci , C. Dozen, I. Dumanoglu, E. Eskut, S. Girgis,G. Gokbulut, E. Gurpinar, I. Hos, E.E. Kangal, A. Kayis Topaksu, G. Onengut , K. Ozdemir,S. Ozturk , A. Polatoz, K. Sogut , D. Sunar Cerci , B. Tali , H. Topakli , M. Vergili Middle East Technical University, Physics Department, Ankara, Turkey
I.V. Akin, B. Bilin, S. Bilmis, H. Gamsizkan, G. Karapinar , K. Ocalan, S. Sekmen, U.E. Surat,M. Yalvac, M. Zeyrek Bogazici University, Istanbul, Turkey
E. G ¨ulmez, B. Isildak , M. Kaya , O. Kaya Istanbul Technical University, Istanbul, Turkey
H. Bahtiyar , E. Barlas, K. Cankocak, F.I. Vardarlı, M. Y ¨ucel National Scientific Center, Kharkov Institute of Physics and Technology, Kharkov, Ukraine
L. Levchuk, P. Sorokin
University of Bristol, Bristol, United Kingdom
J.J. Brooke, E. Clement, D. Cussans, H. Flacher, R. Frazier, J. Goldstein, M. Grimes, G.P. Heath,H.F. Heath, J. Jacob, L. Kreczko, C. Lucas, Z. Meng, D.M. Newbold , S. Paramesvaran, A. Poll,S. Senkin, V.J. Smith, T. Williams A The CMS Collaboration
Rutherford Appleton Laboratory, Didcot, United Kingdom
A. Belyaev , C. Brew, R.M. Brown, D.J.A. Cockerill, J.A. Coughlan, K. Harder, S. Harper,E. Olaiya, D. Petyt, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin, W.J. Womersley,S.D. Worm Imperial College, London, United Kingdom
M. Baber, R. Bainbridge, O. Buchmuller, D. Burton, D. Colling, N. Cripps, M. Cutajar,P. Dauncey, G. Davies, M. Della Negra, P. Dunne, W. Ferguson, J. Fulcher, D. Futyan, A. Gilbert,G. Hall, G. Iles, M. Jarvis, G. Karapostoli, M. Kenzie, R. Lane, R. Lucas , L. Lyons, A.-M. Magnan, S. Malik, B. Mathias, J. Nash, A. Nikitenko , J. Pela, M. Pesaresi, K. Petridis,D.M. Raymond, S. Rogerson, A. Rose, C. Seez, P. Sharp † , A. Tapper, M. Vazquez Acosta,T. Virdee Brunel University, Uxbridge, United Kingdom
J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, D. Leggat, D. Leslie, W. Martin, I.D. Reid,P. Symonds, L. Teodorescu, M. Turner
Baylor University, Waco, USA
J. Dittmann, K. Hatakeyama, A. Kasmi, H. Liu, T. Scarborough
The University of Alabama, Tuscaloosa, USA
O. Charaf, S.I. Cooper, C. Henderson, P. Rumerio
Boston University, Boston, USA
A. Avetisyan, T. Bose, C. Fantasia, P. Lawson, C. Richardson, J. Rohlf, D. Sperka, J. St. John,L. Sulak
Brown University, Providence, USA
J. Alimena, E. Berry, S. Bhattacharya, G. Christopher, D. Cutts, Z. Demiragli, N. Dhingra,A. Ferapontov, A. Garabedian, U. Heintz, G. Kukartsev, E. Laird, G. Landsberg, M. Luk,M. Narain, M. Segala, T. Sinthuprasith, T. Speer, J. Swanson
University of California, Davis, Davis, USA
R. Breedon, G. Breto, M. Calderon De La Barca Sanchez, S. Chauhan, M. Chertok, J. Conway,R. Conway, P.T. Cox, R. Erbacher, M. Gardner, W. Ko, R. Lander, T. Miceli, M. Mulhearn,D. Pellett, J. Pilot, F. Ricci-Tam, M. Searle, S. Shalhout, J. Smith, M. Squires, D. Stolp, M. Tripathi,S. Wilbur, R. Yohay
University of California, Los Angeles, USA
R. Cousins, P. Everaerts, C. Farrell, J. Hauser, M. Ignatenko, G. Rakness, E. Takasugi, V. Valuev,M. Weber
University of California, Riverside, Riverside, USA
J. Babb, K. Burt, R. Clare, J. Ellison, J.W. Gary, G. Hanson, J. Heilman, M. Ivova Rikova, P. Jandir,E. Kennedy, F. Lacroix, H. Liu, O.R. Long, A. Luthra, M. Malberti, H. Nguyen, M. OlmedoNegrete, A. Shrinivas, S. Sumowidagdo, S. Wimpenny
University of California, San Diego, La Jolla, USA
W. Andrews, J.G. Branson, G.B. Cerati, S. Cittolin, R.T. D’Agnolo, D. Evans, A. Holzner,R. Kelley, D. Klein, M. Lebourgeois, J. Letts, I. Macneill, D. Olivito, S. Padhi, C. Palmer, M. Pieri,M. Sani, V. Sharma, S. Simon, E. Sudano, M. Tadel, Y. Tu, A. Vartak, C. Welke, F. W ¨urthwein,A. Yagil, J. Yoo
University of California, Santa Barbara, Santa Barbara, USA
D. Barge, J. Bradmiller-Feld, C. Campagnari, T. Danielson, A. Dishaw, K. Flowers, M. Franco Sevilla, P. Geffert, C. George, F. Golf, L. Gouskos, J. Incandela, C. Justus, N. Mccoll, J. Richman,D. Stuart, W. To, C. West
California Institute of Technology, Pasadena, USA
A. Apresyan, A. Bornheim, J. Bunn, Y. Chen, E. Di Marco, J. Duarte, A. Mott, H.B. Newman,C. Pena, C. Rogan, M. Spiropulu, V. Timciuc, R. Wilkinson, S. Xie, R.Y. Zhu
Carnegie Mellon University, Pittsburgh, USA
V. Azzolini, A. Calamba, B. Carlson, T. Ferguson, Y. Iiyama, M. Paulini, J. Russ, H. Vogel,I. Vorobiev
University of Colorado at Boulder, Boulder, USA
J.P. Cumalat, W.T. Ford, A. Gaz, E. Luiggi Lopez, U. Nauenberg, J.G. Smith, K. Stenson,K.A. Ulmer, S.R. Wagner
Cornell University, Ithaca, USA
J. Alexander, A. Chatterjee, J. Chu, S. Dittmer, N. Eggert, N. Mirman, G. Nicolas Kaufman,J.R. Patterson, A. Ryd, E. Salvati, L. Skinnari, W. Sun, W.D. Teo, J. Thom, J. Thompson, J. Tucker,Y. Weng, L. Winstrom, P. Wittich
Fairfield University, Fairfield, USA
D. Winn
Fermi National Accelerator Laboratory, Batavia, USA
S. Abdullin, M. Albrow, J. Anderson, G. Apollinari, L.A.T. Bauerdick, A. Beretvas, J. Berryhill,P.C. Bhat, K. Burkett, J.N. Butler, H.W.K. Cheung, F. Chlebana, S. Cihangir, V.D. Elvira, I. Fisk,J. Freeman, Y. Gao, E. Gottschalk, L. Gray, D. Green, S. Gr ¨unendahl, O. Gutsche, J. Hanlon,D. Hare, R.M. Harris, J. Hirschauer, B. Hooberman, S. Jindariani, M. Johnson, U. Joshi,K. Kaadze, B. Klima, B. Kreis, S. Kwan, J. Linacre, D. Lincoln, R. Lipton, T. Liu, J. Lykken,K. Maeshima, J.M. Marraffino, V.I. Martinez Outschoorn, S. Maruyama, D. Mason, P. McBride,K. Mishra, S. Mrenna, Y. Musienko , S. Nahn, C. Newman-Holmes, V. O’Dell, O. Prokofyev,E. Sexton-Kennedy, S. Sharma, A. Soha, W.J. Spalding, L. Spiegel, L. Taylor, S. Tkaczyk,N.V. Tran, L. Uplegger, E.W. Vaandering, R. Vidal, A. Whitbeck, J. Whitmore, F. Yang University of Florida, Gainesville, USA
D. Acosta, P. Avery, D. Bourilkov, M. Carver, T. Cheng, D. Curry, S. Das, M. De Gruttola, G.P. DiGiovanni, R.D. Field, M. Fisher, I.K. Furic, J. Hugon, J. Konigsberg, A. Korytov, T. Kypreos,J.F. Low, K. Matchev, P. Milenovic , G. Mitselmakher, L. Muniz, A. Rinkevicius, L. Shchutska,M. Snowball, J. Yelton, M. Zakaria Florida International University, Miami, USA
S. Hewamanage, S. Linn, P. Markowitz, G. Martinez, J.L. Rodriguez
Florida State University, Tallahassee, USA
T. Adams, A. Askew, J. Bochenek, B. Diamond, J. Haas, S. Hagopian, V. Hagopian, K.F. Johnson,H. Prosper, V. Veeraraghavan, M. Weinberg
Florida Institute of Technology, Melbourne, USA
M.M. Baarmand, M. Hohlmann, H. Kalakhety, F. Yumiceva
University of Illinois at Chicago (UIC), Chicago, USA
M.R. Adams, L. Apanasevich, V.E. Bazterra, D. Berry, R.R. Betts, I. Bucinskaite, R. Cavanaugh,O. Evdokimov, L. Gauthier, C.E. Gerber, D.J. Hofman, S. Khalatyan, P. Kurt, D.H. Moon,C. O’Brien, C. Silkworth, P. Turner, N. Varelas A The CMS Collaboration
The University of Iowa, Iowa City, USA
E.A. Albayrak , B. Bilki , W. Clarida, K. Dilsiz, F. Duru, M. Haytmyradov, J.-P. Merlo,H. Mermerkaya , A. Mestvirishvili, A. Moeller, J. Nachtman, H. Ogul, Y. Onel, F. Ozok ,A. Penzo, R. Rahmat, S. Sen, P. Tan, E. Tiras, J. Wetzel, T. Yetkin , K. Yi Johns Hopkins University, Baltimore, USA
B.A. Barnett, B. Blumenfeld, S. Bolognesi, D. Fehling, A.V. Gritsan, P. Maksimovic, C. Martin,M. Swartz
The University of Kansas, Lawrence, USA
P. Baringer, A. Bean, G. Benelli, C. Bruner, J. Gray, R.P. Kenny III, M. Malek, M. Murray,D. Noonan, S. Sanders, J. Sekaric, R. Stringer, Q. Wang, J.S. Wood
Kansas State University, Manhattan, USA
A.F. Barfuss, I. Chakaberia, A. Ivanov, S. Khalil, M. Makouski, Y. Maravin, L.K. Saini,S. Shrestha, N. Skhirtladze, I. Svintradze
Lawrence Livermore National Laboratory, Livermore, USA
J. Gronberg, D. Lange, F. Rebassoo, D. Wright
University of Maryland, College Park, USA
A. Baden, A. Belloni, B. Calvert, S.C. Eno, J.A. Gomez, N.J. Hadley, R.G. Kellogg, T. Kolberg,Y. Lu, M. Marionneau, A.C. Mignerey, K. Pedro, A. Skuja, M.B. Tonjes, S.C. Tonwar
Massachusetts Institute of Technology, Cambridge, USA
A. Apyan, R. Barbieri, G. Bauer, W. Busza, I.A. Cali, M. Chan, L. Di Matteo, V. Dutta, G. GomezCeballos, M. Goncharov, D. Gulhan, M. Klute, Y.S. Lai, Y.-J. Lee, A. Levin, P.D. Luckey, T. Ma,C. Paus, D. Ralph, C. Roland, G. Roland, G.S.F. Stephans, F. St ¨ockli, K. Sumorok, D. Velicanu,J. Veverka, B. Wyslouch, M. Yang, M. Zanetti, V. Zhukova
University of Minnesota, Minneapolis, USA
B. Dahmes, A. Gude, S.C. Kao, K. Klapoetke, Y. Kubota, J. Mans, N. Pastika, R. Rusack,A. Singovsky, N. Tambe, J. Turkewitz
University of Mississippi, Oxford, USA
J.G. Acosta, S. Oliveros
University of Nebraska-Lincoln, Lincoln, USA
E. Avdeeva, K. Bloom, S. Bose, D.R. Claes, A. Dominguez, R. Gonzalez Suarez, J. Keller,D. Knowlton, I. Kravchenko, J. Lazo-Flores, S. Malik, F. Meier, G.R. Snow
State University of New York at Buffalo, Buffalo, USA
J. Dolen, A. Godshalk, I. Iashvili, A. Kharchilava, A. Kumar, S. Rappoccio
Northeastern University, Boston, USA
G. Alverson, E. Barberis, D. Baumgartel, M. Chasco, J. Haley, A. Massironi, D.M. Morse,D. Nash, T. Orimoto, D. Trocino, R.-J. Wang, D. Wood, J. Zhang
Northwestern University, Evanston, USA
K.A. Hahn, A. Kubik, N. Mucia, N. Odell, B. Pollack, A. Pozdnyakov, M. Schmitt, S. Stoynev,K. Sung, M. Velasco, S. Won
University of Notre Dame, Notre Dame, USA
A. Brinkerhoff, K.M. Chan, A. Drozdetskiy, M. Hildreth, C. Jessop, D.J. Karmgard, N. Kellams,K. Lannon, W. Luo, S. Lynch, N. Marinelli, T. Pearson, M. Planer, R. Ruchti, N. Valls, M. Wayne,M. Wolf, A. Woodard The Ohio State University, Columbus, USA
L. Antonelli, J. Brinson, B. Bylsma, L.S. Durkin, S. Flowers, C. Hill, R. Hughes, K. Kotov,T.Y. Ling, D. Puigh, M. Rodenburg, G. Smith, B.L. Winer, H. Wolfe, H.W. Wulsin
Princeton University, Princeton, USA
O. Driga, P. Elmer, P. Hebda, A. Hunt, S.A. Koay, P. Lujan, D. Marlow, T. Medvedeva,M. Mooney, J. Olsen, P. Pirou´e, X. Quan, H. Saka, D. Stickland , C. Tully, J.S. Werner, S.C. Zenz,A. Zuranski University of Puerto Rico, Mayaguez, USA
E. Brownson, H. Mendez, J.E. Ramirez Vargas
Purdue University, West Lafayette, USA
V.E. Barnes, D. Benedetti, G. Bolla, D. Bortoletto, M. De Mattia, Z. Hu, M.K. Jha, M. Jones,K. Jung, M. Kress, N. Leonardo, D. Lopes Pegna, V. Maroussov, P. Merkel, D.H. Miller,N. Neumeister, B.C. Radburn-Smith, X. Shi, I. Shipsey, D. Silvers, A. Svyatkovskiy, F. Wang,W. Xie, L. Xu, H.D. Yoo, J. Zablocki, Y. Zheng
Purdue University Calumet, Hammond, USA
N. Parashar, J. Stupak
Rice University, Houston, USA
A. Adair, B. Akgun, K.M. Ecklund, F.J.M. Geurts, W. Li, B. Michlin, B.P. Padley, R. Redjimi,J. Roberts, J. Zabel
University of Rochester, Rochester, USA
B. Betchart, A. Bodek, R. Covarelli, P. de Barbaro, R. Demina, Y. Eshaq, T. Ferbel, A. Garcia-Bellido, P. Goldenzweig, J. Han, A. Harel, A. Khukhunaishvili, G. Petrillo, D. Vishnevskiy
The Rockefeller University, New York, USA
R. Ciesielski, L. Demortier, K. Goulianos, G. Lungu, C. Mesropian
Rutgers, The State University of New Jersey, Piscataway, USA
S. Arora, A. Barker, J.P. Chou, C. Contreras-Campana, E. Contreras-Campana, D. Duggan,D. Ferencek, Y. Gershtein, R. Gray, E. Halkiadakis, D. Hidas, S. Kaplan, A. Lath, S. Panwalkar,M. Park, R. Patel, S. Salur, S. Schnetzer, S. Somalwar, R. Stone, S. Thomas, P. Thomassen,M. Walker
University of Tennessee, Knoxville, USA
K. Rose, S. Spanier, A. York
Texas A&M University, College Station, USA
O. Bouhali , A. Castaneda Hernandez, R. Eusebi, W. Flanagan, J. Gilmore, T. Kamon ,V. Khotilovich, V. Krutelyov, R. Montalvo, I. Osipenkov, Y. Pakhotin, A. Perloff, J. Roe, A. Rose,A. Safonov, T. Sakuma, I. Suarez, A. Tatarinov Texas Tech University, Lubbock, USA
N. Akchurin, C. Cowden, J. Damgov, C. Dragoiu, P.R. Dudero, J. Faulkner, K. Kovitanggoon,S. Kunori, S.W. Lee, T. Libeiro, I. Volobouev
Vanderbilt University, Nashville, USA
E. Appelt, A.G. Delannoy, S. Greene, A. Gurrola, W. Johns, C. Maguire, Y. Mao, A. Melo,M. Sharma, P. Sheldon, B. Snook, S. Tuo, J. Velkovska A The CMS Collaboration
University of Virginia, Charlottesville, USA
M.W. Arenton, S. Boutle, B. Cox, B. Francis, J. Goodell, R. Hirosky, A. Ledovskoy, H. Li, C. Lin,C. Neu, J. Wood
Wayne State University, Detroit, USA
C. Clarke, R. Harr, P.E. Karchin, C. Kottachchi Kankanamge Don, P. Lamichhane, J. Sturdy
University of Wisconsin, Madison, USA
D.A. Belknap, D. Carlsmith, M. Cepeda, S. Dasu, L. Dodd, S. Duric, E. Friis, R. Hall-Wilton, M. Herndon, A. Herv´e, P. Klabbers, A. Lanaro, C. Lazaridis, A. Levine, R. Loveless,A. Mohapatra, I. Ojalvo, T. Perry, G.A. Pierro, G. Polese, I. Ross, T. Sarangi, A. Savin,W.H. Smith, C. Vuosalo, N. Woods † : Deceased1: Also at Vienna University of Technology, Vienna, Austria2: Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland3: Also at Institut Pluridisciplinaire Hubert Curien, Universit´e de Strasbourg, Universit´e deHaute Alsace Mulhouse, CNRS/IN2P3, Strasbourg, France4: Also at National Institute of Chemical Physics and Biophysics, Tallinn, Estonia5: Also at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University,Moscow, Russia6: Also at Universidade Estadual de Campinas, Campinas, Brazil7: Also at Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France8: Also at Joint Institute for Nuclear Research, Dubna, Russia9: Also at Suez University, Suez, Egypt10: Also at Cairo University, Cairo, Egypt11: Also at Fayoum University, El-Fayoum, Egypt12: Also at British University in Egypt, Cairo, Egypt13: Now at Ain Shams University, Cairo, Egypt14: Also at Universit´e de Haute Alsace, Mulhouse, France15: Also at Brandenburg University of Technology, Cottbus, Germany16: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary17: Also at E ¨otv ¨os Lor´and University, Budapest, Hungary18: Also at University of Debrecen, Debrecen, Hungary19: Also at University of Visva-Bharati, Santiniketan, India20: Now at King Abdulaziz University, Jeddah, Saudi Arabia21: Also at University of Ruhuna, Matara, Sri Lanka22: Also at Isfahan University of Technology, Isfahan, Iran23: Also at Sharif University of Technology, Tehran, Iran24: Also at Plasma Physics Research Center, Science and Research Branch, Islamic AzadUniversity, Tehran, Iran25: Also at Laboratori Nazionali di Legnaro dell’INFN, Legnaro, Italy26: Also at Universit`a degli Studi di Siena, Siena, Italy27: Also at Centre National de la Recherche Scientifique (CNRS) - IN2P3, Paris, France28: Also at Purdue University, West Lafayette, USA29: Also at Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Mexico30: Also at Institute for Nuclear Research, Moscow, Russia31: Also at St. Petersburg State Polytechnical University, St. Petersburg, Russia32: Also at INFN Sezione di Padova; Universit`a di Padova; Universit`a di Trento (Trento),Padova, Italy33: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia5