Measurement of the Underlying Event Activity in Proton-Proton Collisions at 0.9 TeV
EEUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN)
CERN-PH-EP/2010-0142018/11/09
CMS-QCD-10-001
First Measurement of the Underlying Event Activityat the LHC with √ s = The CMS Collaboration ∗ Abstract
A measurement of the underlying activity in scattering processes with p T scale inthe GeV region is performed in proton-proton collisions at √ s = | η | < p T > c , and azimuthal direction transverse to that of the leadingobject. Submitted to the European Physical Journal C ∗ See Appendix A for the list of collaboration members a r X i v : . [ h e p - e x ] J u n In the presence of a “hard” process characterized by large transverse momenta p T with respectto the beam direction, the hadronic final states of hadron-hadron interactions can be describedas the superposition of several contributions: products of the partonic hard scattering with thehighest p T , including initial and final state radiation; hadrons produced in additional “multipleparton interactions” (MPI); and “beam-beam remnants” (BBR) resulting from the hadroniza-tion of the partonic constituents that did not participate in other scatters. Products of MPI andBBR form the “underlying event” (UE). The UE cannot be uniquely separated from initial andfinal state radiation.A good description of UE properties is crucial for precision measurements of Standard Modelprocesses and the search for new physics at the CERN Large Hadron Collider (LHC) [1]. Multi-plicity distributions measured by the UA5 collaboration at the Sp ¯pS collider [2] were modeledin Monte Carlo (MC) simulations [3]. Detailed UE studies performed at the Tevatron by theCDF collaboration [4–6] led to significant progress in MPI modeling [7]. The UE dynamics is,however, not fully understood, especially the centre-of-mass energy dependence. A new en-ergy domain is opening with the LHC, where UE properties can be studied with data taken at √ s = p T . This “leading” object is expected to reflect the direction of the partonproduced with the highest transverse momentum in the hard interaction. Three distinct topo-logical regions in the hadronic final state are thus defined by the azimuthal angle difference ∆ φ between the directions, in the plane transverse to the beam, of the leading object and that of anycharged hadron in the event. Hadron production in the “toward” region with | ∆ φ | < ◦ andin the “away” region with | ∆ φ | > ◦ is expected to be dominated by the hard parton-partonscattering and radiation. The UE structure can be best studied in the “transverse” region with60 ◦ < | ∆ φ | < ◦ .UE dynamics is studied through the confrontation of models with the data. In this paper,MC predictions for charged particle production are compared after full detector simulation tothe data, uncorrected for detector effects. The predictions for inelastic events are calculatedusing several tunes of the PYTHIA programme, version 6.420 [3, 8], which provide differentdescriptions of the non-diffractive component: D6T [9, 10], DW [10], Pro-Q20 [11], Perugia-0(P0) [12], and CW, the last being adapted from the DW tune as described below. They dif-fer, in particular, in the implementation of the regularization of the formal 1/ ˆ p T divergenceof the leading order partonic scattering amplitude as the final state parton transverse mo-mentum ˆ p T approaches 0. In PYTHIA this divergence is regularized through the replacement1/ ˆ p T → ( ˆ p T + ˆ p T ) . The energy dependence of the cutoff transverse momentum ˆ p T is pa-rameterized as ˆ p T ( √ s ) = ˆ p T ( √ s ) · ( √ s / √ s ) (cid:101) , where √ s is the reference energy at whichˆ p T is determined and (cid:101) is a parameter describing the energy dependence. CDF studies [4, 5]favour a value of ˆ p T = c for √ s = p T is used toregularize both MPI and hard scattering, this parameter governs the description of the amountof MPI in the event. More MPI activity is predicted for smaller values of ˆ p T .All tunes considered in this paper are consistent with the UE measurements by CDF. Tunes DW,P0, and Pro-Q20 use (cid:101) = √ s =
630 GeV and 1.8 TeV. TuneD6T uses the value (cid:101) = p T isdecreased to 1.8 GeV/ c and (cid:101) is increased to 0.30, while the parameters controlling the relative weighting of possible color connections in the matrix elements are changed back from the DWvalues to the PYTHIA defaults; these changes lead to a large increase of the simulated MPIactivity at √ s = √ s = z , where z denotes the fraction of the parton momentum carried by a final state particle. TuneP0 uses the new PYTHIA MPI model [16], which is interleaved with parton showering. A detailed description of the CMS detector can be found in [17]; features most relevant for thepresent analysis are described in the following. A right-handed coordinate system is used withthe origin at the nominal interaction point (IP). The x axis points to the centre of the LHC ring,the y axis is vertical and points upward, and the z axis is parallel to the anti-clockwise beamdirection. The azimuthal angle φ is measured with respect to the x axis in the xy plane and thepolar angle θ is defined with respect to the z axis.The pixel and silicon strip tracker, immersed in the axial 3.8 T magnetic field provided by the6 m diameter superconducting solenoid, measures charged particle trajectories in the pseudo-rapidity range | η | < η = − ln ( tan ( θ /2 )) . The p T resolution for 1 GeV/ c chargedparticles is between 0.7% at η = | η | = µ m in the barrel region [18].Three subsystems were involved in the trigger of the detector readout: the forward hadroncalorimeter (HF), the Beam Scintillator Counters (BSC) [17, 19], and the Beam Pick-up Timingfor eXperiments (BPTX) [17, 20]. The steel–quartz-fibre HF covers the region 2.9 < | η | < < | η | < × − .The event selection requires one reconstructed primary vertex [21] with z coordinate within15 cm of the centre of the beam collision region, of which the rms size is about 4 cm. Three ormore tracks must be identified as originating at the vertex. Table 1 gives the numbers of eventsthat pass these selection criteria. A study of data collected with non-colliding beams showedthat beam-induced backgrounds are negligible.Kinematic selections are based on the transverse momentum of the leading charged particle orof the leading track-jet, which must be reconstructed with pseudorapidity | η | <
2. The leadingcharged particle, or “leading track”, must be reconstructed in the tracking detector. The leadingtrack-jet is defined using the SISCone algorithm [22] as implemented in the fastjet package [23]with a clustering radius R = (cid:112) ( ∆ φ ) + ( ∆ η ) = Table 1: Numbers of events in the data satisfying the selection criteria, and correspondingcumulative event fractions in the data and for the simulation based on PYTHIA with tune D6T.In the lower part of the table, the effects of various selection cuts applied to the leading objectwith | η | < z window 238 977 93.7 92.8+ at least 3 tracks associated 230 611 90.4 88.7leading track, p T > c
216 215 93.8 93.2 p T > c
131 421 60.8 55.0 p T > c
28 210 21.5 19.5leading track-jet, p T > c
155 005 67.2 62.9 p T > c
24 928 16.1 15.9Table 2: Numbers of tracks in the selected event sample for successive track selection criteria,and corresponding fractions in the data and for the simulation based on PYTHIA with tuneD6T. Each fraction is given with respect to the previous selection cut.Track selection Data [nb. tracks] Data [%] MC [%]reconstruction algorithm 4 004 923 100 100+ p T > c | η | < | η | < d xy / σ ( d xy ) < d z / σ ( d z ) < σ ( p T ) / p T <
5% 1 168 530 97.0 96.9Total 1 168 530 29.2 29.8in the tracker, with p T > c and | η | < p T . The η range of the charged particles used to define thetrack-jet ( | η | < | η | <
2) in orderto avoid a kinematic bias. A simulation-based study of jets with p T > c indicates thattrack-jets in CMS are found with high efficiency and good angular and energy resolutions [24];this has been verified for softer jets in the present analysis. The results of selection cuts on theleading track and leading track-jet p T are given in Table 1.A detailed simulation of the CMS detector response was performed, based on the GEANT4package [25] with event simulation using PYTHIA tune D6T. The position and shape of thebeam interaction region were adjusted to agree with the data [21]. Simulated events were pro-cessed and reconstructed in the same manner as collision data, and the results of the simulationare also reported in Table 1. Table 3: Systematic uncertainties on track selection and reconstruction (see description in text).The uncertainties, expressed in %, are quoted for characteristic values of variables used for UEstudies in the transverse region. For the first two variables, p T designates the minimal valueof the track-jet p T ; for the last three variables, events with a leading track-jet with p T > c are selected. track tracker tracker bg. trigger dead beam totalsel. align. mater. cont. ch. spot d N ch /d η d ( ∆ φ ) ( p T = c ) 0.3 0.3 1.0 0.8 0.6 0.1 0.5 1.8d Σ p T /d η d ( ∆ φ ) ( p T = c ) 0.4 0.3 1.0 0.8 1.1 0.1 0.5 1.8d N ev /d N ch ( N ch =
4) 0.6 0.6 1.2 1.0 1.2 0.2 0.6 2.3d N ev /d Σ p T ( Σ p T = c ) 0.5 0.2 0.6 0.5 1.2 0.2 0.4 1.6d N ch /d p T ( p T = c ) 0.8 0.6 1.0 0.8 1.0 0.2 0.5 2.0 A charged particle track is selected for the UE analysis if it originates from the primary vertexand is reconstructed in the pixel and silicon strip tracker with transverse momentum p T > c and pseudorapidity | η | <
2. A high purity reconstruction algorithm (see Section 3of [21]) is used, which keeps low levels of fake and poorly reconstructed tracks. To decreasecontamination by secondary tracks from decays of long-lived particles and photon conversions,the distance of closest approach between track and primary vertex is required to be less thanfive times its estimated uncertainty, both in the transverse plane, d xy / σ ( d xy ) <
5, and alongthe z axis, d z / σ ( d z ) <
5. Poorly measured tracks are removed by requiring σ ( p T ) / p T < σ ( p T ) is the uncertainty on the transverse momentum measurement. In the selectedtrack sample with | η | <
2, these cuts result in a background level of 3%, 1% from K S and Λ decay products and 2% from fake tracks.The numbers of tracks accepted at the different selection steps and the corresponding fractionsare given in Table 2, together with the fractions calculated using simulated data. Agreement isobserved at the percent level between data and simulation, for all selection steps.Several systematic uncertainties may affect the comparison of models with the data. Thesources of these uncertainties include the implementation in the simulation of track selectioncriteria, tracker alignment and tracker material content, background contamination, triggerconditions, and run-to-run variations of tracker and beam conditions.The uncertainty in the simulation of track selection has been evaluated by applying varioussets of criteria and comparing their effects to the data and to simulated events.The tracking performance depends on occupancy; because efficiencies and fake rates computedusing different models are found to be consistent within statistical uncertainties, no systematicuncertainty due to occupancy variation is assigned. The effects of tracker misalignment arefound to change the results by less than 1%. The description in the simulation of inactivetracker material has been found to be adequate within 5%; increasing the material densities by5% in the simulation induces a change smaller than 1% in the tracking efficiency and has nosignificant effect on background rates.The simulation has been found to underestimate K S and Λ production as well as photon con-version rates. These discrepancies induce changes of less than 0.5% in the background contam- ination. Increasing the combinatorial background by a conservative 30% leads to a combined0.8% uncertainty due to background description.The uncertainty related to the simulation of the BSC-based trigger is taken to be half of the dif-ference between the distributions obtained with and without trigger simulation. This estimateof the trigger-related systematic uncertainty was verified by means of HF-triggered events forwhich the BSCs had not generated a trigger.The number of inactive tracker channels changes from run to run; reproducing this effect inthe simulation induces a change of less than 0.5% in the observed distributions. The beamcollision region is not perfectly centred within the detector, and its position changes from runto run; simulating different beam spot positions, consistent with those observed in differentruns, leads to a 0.5% uncertainty.The systematic uncertainties are largely independent from one another, but they are correlatedamong data points in the experimental distributions. Table 3 gives the main uncertainties forselected events with a leading track-jet with p T > c , for characteristic values of variablesused for UE studies in the transverse region. Most uncertainties increase by typically 50% whenthe selection requires a leading track with p T > c . Predictions from the various PYTHIA models, after full detector simulation, are compared tothe data. The scale of an interaction at parton level is defined by the p T value of the leadingobject, either a track or a track-jet with | η | <
2. As can be observed in Table 1, demanding aleading particle with p T > c or a leading track-jet with p T > c reduces the samplesize by a similar factor of about 10. h -3 -2 -1 0 1 2 3 h / d c h d N Data 0.9 TeVPYTHIA D6TPYTHIA DWPYTHIA P0PYTHIA Pro-Q20PYTHIA CW
CMS > 1 GeV/c T leading track-jet p > 0.5 GeV/c) T charged particles (p h -3 -2 -1 0 1 2 3 h / d c h d N Data 0.9 TeVPYTHIA D6TPYTHIA DWPYTHIA P0PYTHIA Pro-Q20PYTHIA CW
CMS > 3 GeV/c T leading track-jet p > 0.5 GeV/c) T charged particles (p Figure 1: Average multiplicity, per unit of pseudorapidity, of charged particles with p T > c , as a function of η . The leading track-jet is required to have | η | < p T > c , or (right) p T > c (note the different vertical scales). Predictions from severalPYTHIA MC tunes, including full detector simulation, are compared to the data.Figure 1 presents, as a function of η , the average multiplicity N ch per unit of pseudorapidityof charged particles with p T > c ; for this figure, the track selection is extended to | η | = p T of the leading track-jet. For a harder scale, the multiplicities are larger and charged particleswith p T > c are produced more centrally. The various PYTHIA tunes describe severalfeatures of the data: the overall normalization, the η dependence of particle production, and theeffect of the leading track-jet p T cut. However, no simulation describes perfectly all elementsof the data, either in normalization or in shape. For both values of the minimal p T of track-jets, the data show a significantly stronger η dependence than predicted by the PYTHIA tunes.Predictions of tune CW are too high in normalization, whereas those of tunes D6T, P0, andPro-Q20 are generally too low, with DW being too low in the central region and too high atlarge | η | values. The shape description is slightly better with tunes P0 and Pro-Q20. Similarobservations are made when the selection criteria are applied to the leading track p T . Theobserved features can be due to shortcomings in the description of parton fragmentation andradiation (essentially the toward and away regions), in the description of the UE (visible in thetransverse region), or in both. [degrees] fD -150 -100 -50 0 50 100 150 ) [ G e V / c ] fD d ( h / d T p S d Data 0.9 TeVPYTHIA D6TPYTHIA DW PYTHIA P0 PYTHIA Pro-Q20PYTHIA CW
CMS charged particles| < 2) h > 0.5 GeV/c, | T (p > 1 GeV/c T leading track p [degrees] fD -150 -100 -50 0 50 100 150 ) [ G e V / c ] fD d ( h / d T p S d Data 0.9 TeVPYTHIA D6TPYTHIA DW PYTHIA P0 PYTHIA Pro-Q20PYTHIA CW
CMS charged particles| < 2) h > 0.5 GeV/c, | T (p > 2 GeV/c T leading track p Figure 2: Average scalar sum of transverse momenta of charged particles with p T > c and | η | <
2, per unit of pseudorapidity and per radian, plotted as a function of the azimuthalangle difference ∆ φ relative to the leading track (the measurements have been symmetrized in ∆ φ ). The leading track, which is excluded from the p T sum, is required to have | η | < p T > c , or (right) p T > c (note the different vertical scales). Predictions fromseveral PYTHIA MC tunes, including full detector simulation, are compared to the data.The production of charged particles with p T > c and | η | < ∆ φ between the directions of the leading object and of any se-lected track. As an example, Fig. 2 presents the distribution of d Σ p T /d η d ( ∆ φ ) , where ∑ p T denotes the scalar sum of particle transverse momenta, excluding the leading track at ∆ φ = p T . The char-acteristic features of two-jet parton-parton production with underlying activity are observed.Although the leading track p T is not included in the calculation, the average ∑ p T in the to-ward region, | ∆ φ | < ◦ , shows substantial activity due to parton fragmentation and radiation.Charged hadron production is also significant around the opposite direction, | ∆ φ | > ◦ ; thisis attributed to the fragmentation of the second outgoing parton. In the transverse region with60 ◦ < | ∆ φ | < ◦ , hadron production is depleted but it is nonzero, a feature that is attributedmainly to MPI. Similar features of the event structure are observed for the average track multi-plicity and for selections based on the leading track-jet p T . In the toward region, all PYTHIA tune predictions are significantly above the data, except fortune P0 with the scale p T > c . The poor description by tune Pro-Q20 compared to thatof P0 may appear surprising since both use LEP results on jet fragmentation. A differencebetween these tunes is that P0 incorporates newer MPI modeling and p T ordered showering.Model descriptions are better for the away region, except for the CW and DW tunes, both ofwhich are significantly above the data when the scale is large.The transverse region is most relevant for understanding UE properties. Here, the best tunesare CW and DW. The predictions of the CW model are slightly too high, especially for thehigher p T scale, and those of DW slightly too low; predictions of the other tunes are even lower.In the following, studies of the UE using the transverse region will focus on the comparisonwith data of the predictions of the CW and DW tunes.Figures 3 and 4 provide detailed information on the production of charged particles with p T > c and | η | < ◦ < | ∆ φ | < ◦ . Figure 3 presents thedistributions of the average multiplicity, d N ch /d η d ( ∆ φ ) , and of the average scalar momentumsum, d Σ p T /d η d ( ∆ φ ) , as a function of the scale provided by the p T of the leading track or ofthe leading track-jet. At low p T of the leading object, the multiplicity and the scalar ∑ p T riserapidly with p T , which is attributed to MPI. This fast rise is followed by a slower increasefor leading tracks with p T ∼ > c (left plots) or leading track-jets with p T ∼ > c (rightplots), attributed to a saturation of MPI, plus additional radiation; as expected, a similar scaleis provided by a lower p T value for a leading track than for a leading track-jet. The behaviourof the data is reproduced by both the CW and DW tunes, as well as by the other PYTHIA tunes(not shown), with a better description by CW in the low p T region.The distributions of charged particle multiplicity, of scalar ∑ p T , and of particle p T are pre-sented in Fig. 4 for events selected with a leading track-jet with p T > c . The CW andDW tunes bracket the data over most of the experimental range, and they describe the variousdependences rather well. Similar behaviours are observed for selections based on the leadingtrack p T .The information is summarized in Fig. 5, which presents the ratio of the MC predictions to themeasurements, for the variables presented in Figs. 3 and 4. The shape of the steeply fallinghadron p T spectrum is well described by all tunes, in particular the P0 tune, which achievesgood agreement in the high-momentum tail because of its hard p T spectrum. The CW andDW tunes globally describe the measurement of hadron production in the transverse regionbest, both in normalization and in shape, with the CW predictions generally higher than thedata and the DW predictions lower. A small dependence on the choice of the leading objectis observed, with a preference for CW in the case of a leading track-jet and for DW in the caseof a leading particle (not shown). The predictions of tune D6T are too low and generally theleast consistent with the data. The predictions of tunes Pro-Q20 and P0 tend to lie between thepredictions of tunes D6T and DW. This paper describes a study of the production of hadrons with p T > c and | η | < √ s = c .Particular attention has been devoted to the transverse region, defined by the difference inazimuthal angle between the leading object and charged particle directions, 60 ◦ < | ∆ φ | < ◦ , [GeV/c] T Leading track p ) fD d ( h / d c h N d Data 0.9 TeVPYTHIA DWPYTHIA CW charged particles) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p CMS [GeV/c] T Leading track-jet p ) fD d ( h / d c h N d Data 0.9 TeVPYTHIA DWPYTHIA CW charged particles) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p CMS [GeV/c] T Leading track p ) [ G e V / c ] fD d ( h / d T p S d Data 0.9 TeVPYTHIA DWPYTHIA CW charged particles) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p CMS [GeV/c] T Leading track-jet p ) [ G e V / c ] fD d ( h / d T p S d Data 0.9 TeVPYTHIA DWPYTHIA CW charged particles) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p CMS
Figure 3: For charged particles with p T > c and | η | < ◦ < | ∆ φ | < ◦ : (upper plots) average multiplicity, and (lower plots) average scalar ∑ p T ,per unit of pseudorapidity and per radian, as a function of (left plots) the p T of the leadingtrack, and (right plots) the p T of the leading track-jet. The inner error bars indicate the sta-tistical uncertainty and the outer error bars the total experimental uncertainty (statistical andsystematic uncertainties added in quadrature); statistical errors dominate. Predictions of theDW and CW PYTHIA MC tunes, including full detector simulation, are compared to the data. ch N c h / d N e v ) d N e v ( / N -5 -4 -3 -2 -1 Data 0.9 TeVPYTHIA DWPYTHIA CW
CMS > 3 GeV/c T leading track-jet pcharged particles ) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p [GeV/c] T p S ] - [ ( G e V / c ) T p S / d e v ) d N e v ( / N -5 -4 -3 -2 -1 Data 0.9 TeVPYTHIA DWPYTHIA CW
CMS > 3 GeV/c T leading track-jet pcharged particles ) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p [GeV/c] T p ] - [ ( G e V / c ) T / dp c h d N -5 -4 -3 -2 -1 Data 0.9 TeVPYTHIA DWPYTHIA CW
CMS > 3 GeV/c T leading track-jet pcharged particles ) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p Figure 4: For charged particles with p T > c and | η | < ◦ < | ∆ φ | < ◦ : (upper left) normalized multiplicity distribution; (upper right) normal-ized scalar ∑ p T distribution; (bottom) p T spectrum. The leading track-jet is required to have | η | < p T > c . The inner error bars indicate the statistical uncertainty and the outererror bars the total experimental uncertainty (statistical and systematic uncertainties added inquadrature); statistical errors dominate. Predictions of the DW and CW PYTHIA MC tunes,including full detector simulation, are compared to the data. [GeV/c] T Leading track-jet p ) M C / D a t a fD d ( h / d c h N d PYTHIA D6TPYTHIA DWPYTHIA P0PYTHIA Pro-Q20PYTHIA CWsyst.syst. + stat.
Data 0.9 TeVcharged particles) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p CMS [GeV/c] T Leading track-jet p ) M C / D a t a fD d ( h / d T p S d PYTHIA D6TPYTHIA DWPYTHIA P0PYTHIA Pro-Q20PYTHIA CWsyst.syst. + stat.
CMS
Data 0.9 TeVcharged particles) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (pch N M C / D a t a c h / d N e v ) d N e v ( / N PYTHIA D6TPYTHIA DWPYTHIA P0PYTHIA Pro-Q20PYTHIA CWsyst.syst. + stat.
CMS > 3 GeV/c T leading track-jet pData 0.9 TeVcharged particles ) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p [GeV/c] T p S M C / D a t a T p S / d e v ) d N e v ( / N PYTHIA D6TPYTHIA DWPYTHIA P0PYTHIA Pro-Q20PYTHIA CWsyst.syst. + stat.
CMS > 3 GeV/c T leading track-jet pData 0.9 TeVcharged particles ) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p [GeV/c] T p M C / D a t a T / dp c h d N PYTHIA D6TPYTHIA DWPYTHIA P0PYTHIA Pro-Q20PYTHIA CWsyst.syst. + stat.
CMS > 3 GeV/c T leading track-jet pData 0.9 TeVcharged particles ) (cid:176) | < 120 fD < | (cid:176) | < 2, 60 h > 0.5 GeV/c, | T (p Figure 5: Ratios of various MC predictions, including full detector simulation, to the measure-ments of hadrons with p T > c and | η | < ◦ < | ∆ φ | < ◦ :(from top left to bottom) average multiplicity of charged particles, as a function of the leadingtrack-jet p T (cf. Fig. 3, upper right); average scalar ∑ p T , as a function of the leading track-jet p T (cf. Fig. 3, lower right); distribution of the charged particle multiplicity (cf. Fig. 4, upperleft); distribution of the scalar ∑ p T (cf. Fig. 4, upper right); p T spectrum (cf. Fig. 4, bottom).The inner bands correspond to the systematic uncertainties and the outer bands to the totalexperimental uncertainty (systematic and statistical uncertainties added in quadrature). which is most appropriate for the study of the underlying event.The predictions of several PYTHIA MC models, after full detector simulation, have been com-pared to the data. The models are all consistent with data taken at the Tevatron at √ s = p T cutoff aimed at regularizingsingularities in hard scattering and MPI. The present data favour an energy dependence of thisparameter along the lines of PYTHIA tune DW ( (cid:101) = (cid:101) = (cid:101) , as in tune D6T ( (cid:101) = √ s = Acknowledgments
We wish to congratulate our colleagues in the CERN accelerator departments for the excellentperformance of the LHC machine. We thank the technical and administrative staff at CERN andother CMS institutes for their devoted efforts during the design, construction and operation ofCMS. The cost of the detectors, computing infrastructure, data acquisition and all other sys-tems without which CMS would not be able to operate was supported by the financing agen-cies involved in the experiment. We are particularly indebted to: the Austrian Federal Min-istry of Science and Research; the Belgium Fonds de la Recherche Scientifique, and Fonds voorWetenschappelijk Onderzoek; the Brazilian Funding Agencies (CNPq, CAPES, FAPERJ, andFAPESP); the Bulgarian Ministry of Education and Science; CERN; the Chinese Academy of Sci-ences, Ministry of Science and Technology, and National Natural Science Foundation of China;the Colombian Funding Agency (COLCIENCIAS); the Croatian Ministry of Science, Educationand Sport; the Research Promotion Foundation, Cyprus; the Estonian Academy of Sciencesand NICPB; the Academy of Finland, Finnish Ministry of Education, and Helsinki Institute ofPhysics; the Institut National de Physique Nucl´eaire et de Physique des Particules / CNRS,and Commissariat `a l’ ´Energie Atomique, France; the Bundesministerium f ¨ur Bildung undForschung, Deutsche Forschungsgemeinschaft, and Helmholtz-Gemeinschaft Deutscher For-schungszentren, Germany; the General Secretariat for Research and Technology, Greece; theNational Scientific Research Foundation, and National Office for Research and Technology,Hungary; the Department of Atomic Energy, and Department of Science and Technology, In-dia; the Institute for Studies in Theoretical Physics and Mathematics, Iran; the Science Founda-tion, Ireland; the Istituto Nazionale di Fisica Nucleare, Italy; the Korean Ministry of Education,Science and Technology and the World Class University program of NRF, Korea; the Lithua-nian Academy of Sciences; the Mexican Funding Agencies (CINVESTAV, CONACYT, SEP, andUASLP-FAI); the Pakistan Atomic Energy Commission; the State Commission for Scientific Re-search, Poland; the Fundac¸ ˜ao para a Ciˆencia e a Tecnologia, Portugal; JINR (Armenia, Belarus,Georgia, Ukraine, Uzbekistan); the Ministry of Science and Technologies of the Russian Fed-eration, and Russian Ministry of Atomic Energy; the Ministry of Science and TechnologicalDevelopment of Serbia; the Ministerio de Ciencia e Innovacion, and Programa Consolider-Ingenio 2010, Spain; the Swiss Funding Agencies (ETH Board, ETH Zurich, PSI, SNF, UniZH,Canton Zurich, and SER); the National Science Council, Taipei; the Scientific and Technical Re- search Council of Turkey, and Turkish Atomic Energy Authority; the Science and TechnologyFacilities Council, UK; the US Department of Energy, and the US National Science Foundation.Individuals have received support from the Marie-Curie IEF program (European Union); theLeventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation;and the Associazione per lo Sviluppo Scientifico e Tecnologico del Piemonte (Italy). References [1] L. Evans and P. Bryant, (eds.), “LHC Machine”,
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A506 (2003) 250. doi:10.1016/S0168-9002(03)01368-8 . 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,J. Hammer , S. H¨ansel, M. Hoch, N. H ¨ormann, J. Hrubec, M. Jeitler, G. Kasieczka,W. Kiesenhofer, M. Krammer, D. Liko, I. Mikulec, M. Pernicka, H. Rohringer, R. Sch ¨ofbeck,J. Strauss, A. Taurok, F. Teischinger, W. Waltenberger, G. Walzel, E. Widl, C.-E. Wulz National Centre for Particle and High Energy Physics, Minsk, Belarus
V. Mossolov, N. Shumeiko, J. Suarez Gonzalez
Universiteit Antwerpen, Antwerpen, Belgium
L. Benucci, L. Ceard, E.A. De Wolf, M. Hashemi, X. Janssen, T. Maes, L. Mucibello, S. Ochesanu,B. Roland, R. Rougny, M. Selvaggi, H. Van Haevermaet, P. Van Mechelen, N. Van Remortel
Vrije Universiteit Brussel, Brussel, Belgium
V. Adler, S. Beauceron, S. Blyweert, J. D’Hondt, O. Devroede, A. Kalogeropoulos, J. Maes,M. Maes, S. Tavernier, W. Van Doninck, P. Van Mulders, I. Villella
Universit´e Libre de Bruxelles, Bruxelles, Belgium
E.C. Chabert, O. Charaf, B. Clerbaux, G. De Lentdecker, V. Dero, A.P.R. Gay, G.H. Hammad,P.E. Marage, C. Vander Velde, P. Vanlaer, J. Wickens
Ghent University, Ghent, Belgium
S. Costantini, M. Grunewald, B. Klein, A. Marinov, D. Ryckbosch, F. Thyssen, M. Tytgat,L. Vanelderen, P. Verwilligen, S. Walsh, N. Zaganidis
Universit´e Catholique de Louvain, Louvain-la-Neuve, Belgium
S. Basegmez, G. Bruno, J. Caudron, J. De Favereau De Jeneret, C. Delaere, P. Demin, D. Favart,A. Giammanco, G. Gr´egoire, J. Hollar, V. Lemaitre, O. Militaru, S. Ovyn, D. Pagano, A. Pin,K. Piotrzkowski , L. Quertenmont, N. Schul Universit´e de Mons, Mons, Belgium
N. Beliy, T. Caebergs, E. Daubie
Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil
G.A. Alves, M. Carneiro, M.E. Pol, M.H.G. Souza
Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
W. Carvalho, E.M. Da Costa, D. De Jesus Damiao, C. De Oliveira Martins, S. Fonseca De Souza,L. Mundim, H. Nogima, V. Oguri, A. Santoro, S.M. Silva Do Amaral, A. Sznajder, F. Torres DaSilva De Araujo
Instituto de Fisica Teorica, Universidade Estadual Paulista, Sao Paulo, Brazil
F.A. Dias, M.A.F. Dias, T.R. Fernandez Perez Tomei, E. M. Gregores , F. Marinho, S.F. Novaes,Sandra S. Padula Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
N. Darmenov , L. Dimitrov, V. Genchev , P. Iaydjiev , S. Piperov, S. Stoykova, G. Sultanov,R. Trayanov, I. Vankov A The CMS Collaboration
University of Sofia, Sofia, Bulgaria
M. Dyulendarova, R. Hadjiiska, V. Kozhuharov, L. Litov, E. Marinova, M. Mateev, B. Pavlov,P. Petkov
Institute of High Energy Physics, Beijing, China
J.G. Bian, G.M. Chen, H.S. Chen, C.H. Jiang, D. Liang, S. Liang, J. Wang, J. Wang, X. Wang,Z. Wang, M. Yang, J. Zang, Z. Zhang
State Key Lab. of Nucl. Phys. and Tech., Peking University, Beijing, China
Y. Ban, S. Guo, Z. Hu, Y. Mao, S.J. Qian, H. Teng, B. Zhu
Universidad de Los Andes, Bogota, Colombia
A. Cabrera, C.A. Carrillo Montoya, B. Gomez Moreno, A.A. Ocampo Rios, A.F. Osorio Oliveros,J.C. Sanabria
Technical University of Split, Split, Croatia
N. Godinovic, D. Lelas, K. Lelas, R. Plestina , D. Polic, I. Puljak University of Split, Split, Croatia
Z. Antunovic, M. Dzelalija
Institute Rudjer Boskovic, Zagreb, Croatia
V. Brigljevic, S. Duric, K. Kadija, S. Morovic
University of Cyprus, Nicosia, Cyprus
A. Attikis, R. Fereos, M. Galanti, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis, H. Rykaczewski
Academy of Scientific Research and Technology of the Arab Republic of Egypt, EgyptianNetwork of High Energy Physics, Cairo, Egypt
M.A. Mahmoud National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
A. Hektor, M. Kadastik, K. Kannike, M. M ¨untel, M. Raidal, L. Rebane
Department of Physics, University of Helsinki, Helsinki, Finland
V. Azzolini, P. Eerola
Helsinki Institute of Physics, Helsinki, Finland
S. Czellar, J. H¨ark ¨onen, A. Heikkinen, V. Karim¨aki, R. Kinnunen, J. Klem, M.J. Kortelainen,T. Lamp´en, K. Lassila-Perini, S. Lehti, T. Lind´en, P. Luukka, T. M¨aenp¨a¨a, E. Tuominen,J. Tuominiemi, E. Tuovinen, D. Ungaro, L. Wendland
Lappeenranta University of Technology, Lappeenranta, Finland
K. Banzuzi, A. Korpela, T. Tuuva
Laboratoire d’Annecy-le-Vieux de Physique des Particules, IN2P3-CNRS, Annecy-le-Vieux,France
D. Sillou
DSM/IRFU, CEA/Saclay, Gif-sur-Yvette, France
M. Besancon, M. Dejardin, D. Denegri, J. Descamps, B. Fabbro, J.L. Faure, F. Ferri, S. Ganjour,F.X. Gentit, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, E. Locci, J. Malcles,M. Marionneau, L. Millischer, J. Rander, A. Rosowsky, D. Rousseau, M. Titov, P. Verrecchia
Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
S. Baffioni, L. Bianchini, M. Bluj , C. Broutin, P. Busson, C. Charlot, L. Dobrzynski, S. Elgammal, R. Granier de Cassagnac, M. Haguenauer, A. Kalinowski, P. Min´e, P. Paganini, D. Sabes,Y. Sirois, C. Thiebaux, A. Zabi
Institut Pluridisciplinaire Hubert Curien, Universit´e de Strasbourg, Universit´e de HauteAlsace Mulhouse, CNRS/IN2P3, Strasbourg, France
J.-L. Agram , A. Besson, D. Bloch, D. Bodin, J.-M. Brom, M. Cardaci, E. Conte , F. Drouhin ,C. Ferro, J.-C. Fontaine , D. Gel´e, U. Goerlach, S. Greder, P. Juillot, M. Karim , A.-C. Le Bihan,Y. Mikami, J. Speck, P. Van Hove Centre de Calcul de l’Institut National de Physique Nucleaire et de Physique desParticules (IN2P3), Villeurbanne, France
F. Fassi, D. Mercier
Universit´e de Lyon, Universit´e Claude Bernard Lyon 1, CNRS-IN2P3, Institut de PhysiqueNucl´eaire de Lyon, Villeurbanne, France
C. Baty, N. Beaupere, M. Bedjidian, O. Bondu, G. Boudoul, D. Boumediene, H. Brun,N. Chanon, R. Chierici, D. Contardo, P. Depasse, H. El Mamouni, J. Fay, S. Gascon, B. Ille,T. Kurca, T. Le Grand, M. Lethuillier, L. Mirabito, S. Perries, V. Sordini, S. Tosi, Y. Tschudi,P. Verdier, H. Xiao
E. Andronikashvili Institute of Physics, Academy of Science, Tbilisi, Georgia
V. Roinishvili
RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany
G. Anagnostou, M. Edelhoff, L. Feld, N. Heracleous, O. Hindrichs, R. Jussen, K. Klein, J. Merz,N. Mohr, A. Ostapchuk, A. Perieanu, F. Raupach, J. Sammet, S. Schael, D. Sprenger, H. Weber,M. Weber, B. Wittmer
RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany
O. Actis, M. Ata, W. Bender, P. Biallass, M. Erdmann, J. Frangenheim, T. Hebbeker,A. Hinzmann, K. Hoepfner, C. Hof, M. Kirsch, T. Klimkovich, P. Kreuzer , D. Lanske † ,C. Magass, M. Merschmeyer, A. Meyer, P. Papacz, H. Pieta, H. Reithler, S.A. Schmitz,L. Sonnenschein, M. Sowa, J. Steggemann, D. Teyssier, C. Zeidler RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany
M. Bontenackels, M. Davids, M. Duda, G. Fl ¨ugge, H. Geenen, M. Giffels, W. Haj Ahmad,D. Heydhausen, T. Kress, Y. Kuessel, A. Linn, A. Nowack, L. Perchalla, O. Pooth, P. Sauerland,A. Stahl, M. Thomas, D. Tornier, M.H. Zoeller
Deutsches Elektronen-Synchrotron, Hamburg, Germany
M. Aldaya Martin, W. Behrenhoff, U. Behrens, M. Bergholz, K. Borras, A. Campbell, E. Castro,D. Dammann, G. Eckerlin, A. Flossdorf, G. Flucke, A. Geiser, J. Hauk, H. Jung, M. Kasemann,I. Katkov, C. Kleinwort, H. Kluge, A. Knutsson, E. Kuznetsova, W. Lange, W. Lohmann,R. Mankel, M. Marienfeld, I.-A. Melzer-Pellmann, A.B. Meyer, J. Mnich, A. Mussgiller, J. Olzem,A. Parenti, A. Raspereza, R. Schmidt, T. Schoerner-Sadenius, N. Sen, M. Stein, J. Tomaszewska,D. Volyanskyy, C. Wissing
University of Hamburg, Hamburg, Germany
C. Autermann, J. Draeger, D. Eckstein, H. Enderle, U. Gebbert, K. Kaschube, G. Kaussen,R. Klanner, B. Mura, S. Naumann-Emme, F. Nowak, C. Sander, H. Schettler, P. Schleper,M. Schr ¨oder, T. Schum, J. Schwandt, A.K. Srivastava, H. Stadie, G. Steinbr ¨uck, J. Thomsen,R. Wolf A The CMS Collaboration
Institut f ¨ur Experimentelle Kernphysik, Karlsruhe, Germany
J. Bauer, V. Buege, A. Cakir, T. Chwalek, D. Daeuwel, W. De Boer, A. Dierlamm, G. Dirkes,M. Feindt, J. Gruschke, C. Hackstein, F. Hartmann, M. Heinrich, H. Held, K.H. Hoffmann,S. Honc, T. Kuhr, D. Martschei, S. Mueller, Th. M ¨uller, M. Niegel, O. Oberst, A. Oehler, J. Ott,T. Peiffer, D. Piparo, G. Quast, K. Rabbertz, F. Ratnikov, M. Renz, A. Sabellek, C. Saout,A. Scheurer, P. Schieferdecker, F.-P. Schilling, G. Schott, H.J. Simonis, F.M. Stober, D. Troendle,J. Wagner-Kuhr, M. Zeise, V. Zhukov , E.B. Ziebarth Institute of Nuclear Physics ”Demokritos”, Aghia Paraskevi, Greece
G. Daskalakis, T. Geralis, A. Kyriakis, D. Loukas, I. Manolakos, A. Markou, C. Markou,C. Mavrommatis, E. Petrakou
University of Athens, Athens, Greece
L. Gouskos, P. Katsas, A. Panagiotou University of Io´annina, Io´annina, Greece
I. Evangelou, P. Kokkas, N. Manthos, I. Papadopoulos, V. Patras, F.A. Triantis
KFKI Research Institute for Particle and Nuclear Physics, Budapest, Hungary
A. Aranyi, G. Bencze, L. Boldizsar, G. Debreczeni, C. Hajdu , D. Horvath , A. Kapusi,K. Krajczar , A. Laszlo, F. Sikler, G. Vesztergombi Institute of Nuclear Research ATOMKI, Debrecen, Hungary
N. Beni, J. Molnar, J. Palinkas, Z. Szillasi , V. Veszpremi University of Debrecen, Debrecen, Hungary
P. Raics, Z.L. Trocsanyi, B. Ujvari
Panjab University, Chandigarh, India
S. Bansal, S.B. Beri, V. Bhatnagar, M. Jindal, M. Kaur, J.M. Kohli, M.Z. Mehta, N. Nishu,L.K. Saini, A. Sharma, R. Sharma, A.P. Singh, J.B. Singh, S.P. Singh
University of Delhi, Delhi, India
S. Ahuja, S. Bhattacharya, S. Chauhan, B.C. Choudhary, P. Gupta, S. Jain, S. Jain, A. Kumar,K. Ranjan, R.K. Shivpuri
Bhabha Atomic Research Centre, Mumbai, India
R.K. Choudhury, D. Dutta, S. Kailas, S.K. Kataria, A.K. Mohanty, L.M. Pant, P. Shukla,P. Suggisetti
Tata Institute of Fundamental Research - EHEP, Mumbai, India
T. Aziz, M. Guchait , A. Gurtu, M. Maity , D. Majumder, G. Majumder, K. Mazumdar,G.B. Mohanty, A. Saha, K. Sudhakar, N. Wickramage Tata Institute of Fundamental Research - HECR, Mumbai, India
S. Banerjee, S. Dugad, N.K. Mondal
Institute for Studies in Theoretical Physics & Mathematics (IPM), Tehran, Iran
H. Arfaei, H. Bakhshiansohi, A. Fahim, A. Jafari, M. Mohammadi Najafabadi, S. PaktinatMehdiabadi, B. Safarzadeh, M. Zeinali
INFN Sezione di Bari a , Universit`a di Bari b , Politecnico di Bari c , Bari, Italy M. Abbrescia a , b , L. Barbone a , A. Colaleo a , D. Creanza a , c , N. De Filippis a , M. De Palma a , b ,A. Dimitrov a , F. Fedele a , L. Fiore a , G. Iaselli a , c , L. Lusito a , b ,1 , G. Maggi a , c , M. Maggi a ,N. Manna a , b , B. Marangelli a , b , S. My a , c , S. Nuzzo a , b , G.A. Pierro a , A. Pompili a , b , G. Pugliese a , c ,F. Romano a , c , G. Roselli a , b , G. Selvaggi a , b , L. Silvestris a , R. Trentadue a , S. Tupputi a , b , 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 , S. Braibant-Giacomelli 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 ,1 , F. Fabbri a ,A. Fanfani a , b , D. Fasanella a , P. Giacomelli a , M. Giunta a ,1 , S. Marcellini a , G. Masetti a , b ,A. Montanari a , F.L. Navarria a , b , F. Odorici a , A. Perrotta a , T. Rovelli a , b , G. Siroli a , b ,R. Travaglini a , b INFN Sezione di Catania a , Universit`a di Catania b , Catania, Italy S. Albergo a , b , G. Cappello a , b , M. Chiorboli a , b , S. Costa a , b , A. Tricomi a , b , C. Tuve a INFN Sezione di Firenze a , Universit`a di Firenze b , Firenze, Italy G. Barbagli a , G. Broccolo a , b , V. Ciulli a , b , C. Civinini a , R. D’Alessandro a , b , E. Focardi a , b ,S. Frosali a , b , E. Gallo a , C. Genta a , b , P. Lenzi a , b ,1 , M. Meschini a , S. Paoletti a , G. Sguazzoni a ,A. Tropiano a INFN Laboratori Nazionali di Frascati, Frascati, Italy
L. Benussi, S. Bianco, S. Colafranceschi , F. Fabbri, D. Piccolo INFN Sezione di Genova, Genova, Italy
P. Fabbricatore, R. Musenich
INFN Sezione di Milano-Biccoca a , Universit`a di Milano-Bicocca b , Milano, Italy A. Benaglia a , b , G.B. Cerati a , b ,1 , F. De Guio a , b , L. Di Matteo a , b , A. Ghezzi a , b ,1 , P. Govoni a , b ,M. Malberti a , b ,1 , S. Malvezzi a , A. Martelli a , b ,3 , A. Massironi a , b , D. Menasce a , V. Miccio a , b ,L. Moroni a , P. Negri a , b , M. Paganoni a , b , D. Pedrini a , S. Ragazzi a , b , N. Redaelli a , S. Sala a ,R. Salerno a , b , T. Tabarelli de Fatis a , b , V. Tancini a , b , S. Taroni a , b INFN Sezione di Napoli a , Universit`a di Napoli ”Federico II” b , Napoli, Italy S. Buontempo a , A. Cimmino a , b , A. De Cosa a , b ,1 , M. De Gruttola a , b ,1 , F. Fabozzi a ,13 ,A.O.M. Iorio a , L. Lista a , P. Noli a , b , P. Paolucci a INFN Sezione di Padova a , Universit`a di Padova b , Universit`a di Trento (Trento) c , Padova,Italy P. Azzi a , N. Bacchetta a , P. Bellan a , b ,1 , D. Bisello a , b , R. Carlin a , b , P. Checchia a , M. De Mattia a , b ,T. Dorigo a , U. Dosselli a , F. Gasparini a , b , P. Giubilato a , b , A. Gresele a , c , M. Gulmini a ,14 ,S. Lacaprara a ,14 , I. Lazzizzera a , c , M. Margoni a , b , M. Mazzucato a , A.T. Meneguzzo a , b ,M. Passaseo a , L. Perrozzi a , N. Pozzobon a , b , P. Ronchese a , b , F. Simonetto a , b , E. Torassa a ,M. Tosi a , b , A. Triossi a , S. Vanini a , b , S. Ventura a , P. Zotto a , b INFN Sezione di Pavia a , Universit`a di Pavia b , Pavia, Italy P. Baesso a , b , U. Berzano a , C. Riccardi a , b , P. Torre a , b , P. Vitulo a , b , C. Viviani a , b INFN Sezione di Perugia a , Universit`a di Perugia b , Perugia, Italy M. Biasini a , b , G.M. Bilei a , B. Caponeri a , b , L. Fan `o a , P. Lariccia a , b , A. Lucaroni a , b ,G. Mantovani a , b , M. Menichelli a , A. Nappi a , b , A. Santocchia a , b , L. Servoli a , M. Valdata a ,R. Volpe a , b ,1 INFN Sezione di Pisa a , Universit`a di Pisa b , Scuola Normale Superiore di Pisa c , Pisa, Italy P. Azzurri a , c , G. Bagliesi a , J. Bernardini a , b ,1 , T. Boccali a ,1 , R. Castaldi a , R.T. Dagnolo a , c ,R. Dell’Orso a , F. Fiori a , b , L. Fo`a a , c , A. Giassi a , A. Kraan a , F. Ligabue a , c , T. Lomtadze a , L. Martini a ,A. Messineo a , b , F. Palla a , F. Palmonari a , G. Segneri a , A.T. Serban a , P. Spagnolo a ,1 , R. Tenchini a ,1 ,G. Tonelli a , b ,1 , A. Venturi a , P.G. Verdini a A The CMS Collaboration
INFN Sezione di Roma a , Universit`a di Roma ”La Sapienza” b , Roma, Italy L. Barone a , b , F. Cavallari a ,1 , D. Del Re a , b , E. Di Marco a , b , M. Diemoz a , D. Franci a , b , M. Grassi a ,E. Longo a , b , G. Organtini a , b , A. Palma a , b , F. Pandolfi a , b , R. Paramatti a ,1 , S. Rahatlou a , b ,1 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 , b , S. Argiro a , b , M. Arneodo a , c , C. Biino a , C. Botta a , b ,N. Cartiglia a , R. Castello a , b , M. Costa a , b , N. Demaria a , A. Graziano a , b , C. Mariotti a ,M. Marone a , b , S. Maselli a , E. Migliore a , b , G. Mila a , b , V. Monaco a , b , M. Musich a , b ,M.M. Obertino a , c , N. Pastrone a , M. Pelliccioni a , b ,1 , A. Romero a , b , M. Ruspa a , c , R. Sacchi a , b ,A. Solano a , b , A. Staiano a , D. Trocino a , b , A. Vilela Pereira a , b ,1 INFN Sezione di Trieste a , Universit`a di Trieste b , Trieste, Italy F. Ambroglini a , b , S. Belforte a , F. Cossutti a , G. Della Ricca a , b , B. Gobbo a , D. Montanino a ,A. Penzo a Kyungpook National University, Daegu, Korea
S. Chang, J. Chung, D.H. Kim, G.N. Kim, J.E. Kim, D.J. Kong, H. Park, D. Son, D.C. Son
Chonnam National University, Institute for Universe and Elementary Particles, Kwangju,Korea
Zero Kim, J.Y. Kim, S. Song
Korea University, Seoul, Korea
B. Hong, H. Kim, J.H. Kim, T.J. Kim, K.S. Lee, D.H. Moon, S.K. Park, H.B. Rhee, K.S. Sim
University of Seoul, Seoul, Korea
M. Choi, S. Kang, H. Kim, C. Park, I.C. Park, S. Park
Sungkyunkwan University, Suwon, Korea
S. Choi, Y. Choi, Y.K. Choi, J. Goh, J. Lee, S. Lee, H. Seo, I. Yu
Vilnius University, Vilnius, Lithuania
M. Janulis, D. Martisiute, P. Petrov, T. Sabonis
Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico
H. Castilla Valdez , E. De La Cruz Burelo, R. Lopez-Fernandez, A. S´anchez Hern´andez,L.M. Villase ˜nor-Cendejas Universidad Iberoamericana, Mexico City, Mexico
S. Carrillo Moreno
Benemerita Universidad Autonoma de Puebla, Puebla, Mexico
H.A. Salazar Ibarguen
Universidad Aut ´onoma de San Luis Potos´ı, San Luis Potos´ı, Mexico
E. Casimiro Linares, A. Morelos Pineda, M.A. Reyes-Santos
University of Auckland, Auckland, New Zealand
P. Allfrey, D. Krofcheck, J. Tam
University of Canterbury, Christchurch, New Zealand
P.H. Butler, T. Signal, J.C. Williams
National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan
M. Ahmad, I. Ahmed, M.I. Asghar, H.R. Hoorani, W.A. Khan, T. Khurshid, S. Qazi Institute of Experimental Physics, Warsaw, Poland
M. Cwiok, W. Dominik, K. Doroba, M. Konecki, J. Krolikowski
Soltan Institute for Nuclear Studies, Warsaw, Poland
T. Frueboes, R. Gokieli, M. G ´orski, M. Kazana, K. Nawrocki, M. Szleper, G. Wrochna,P. Zalewski
Laborat ´orio de Instrumenta¸c˜ao e F´ısica Experimental de Part´ıculas, Lisboa, Portugal
N. Almeida, A. David, P. Faccioli, P.G. Ferreira Parracho, M. Gallinaro, G. Mini, P. Musella,A. Nayak, L. Raposo, P.Q. Ribeiro, J. Seixas, P. Silva, D. Soares, J. Varela , H.K. W ¨ohri Joint Institute for Nuclear Research, Dubna, Russia
I. Belotelov, P. Bunin, M. Finger, M. Finger Jr., I. Golutvin, A. Kamenev, V. Karjavin, G. Kozlov,A. Lanev, P. Moisenz, V. Palichik, V. Perelygin, S. Shmatov, V. Smirnov, A. Volodko, A. Zarubin
Petersburg Nuclear Physics Institute, Gatchina (St Petersburg), Russia
N. Bondar, V. Golovtsov, Y. Ivanov, V. Kim, P. Levchenko, I. Smirnov, V. Sulimov, L. Uvarov,S. Vavilov, A. Vorobyev
Institute for Nuclear Research, Moscow, Russia
Yu. Andreev, S. Gninenko, N. Golubev, M. Kirsanov, N. Krasnikov, V. Matveev, A. Pashenkov,A. Toropin, S. Troitsky
Institute for Theoretical and Experimental Physics, Moscow, Russia
V. Epshteyn, V. Gavrilov, N. Ilina, V. Kaftanov † , M. Kossov , A. Krokhotin, S. Kuleshov,A. Oulianov, G. Safronov, S. Semenov, I. Shreyber, V. Stolin, E. Vlasov, A. Zhokin Moscow State University, Moscow, Russia
E. Boos, M. Dubinin , L. Dudko, A. Ershov, A. Gribushin, O. Kodolova, I. Lokhtin,S. Obraztsov, S. Petrushanko, L. Sarycheva, V. Savrin, A. Snigirev P.N. Lebedev Physical Institute, Moscow, Russia
V. Andreev, I. Dremin, M. Kirakosyan, S.V. Rusakov, A. Vinogradov
State Research Center of Russian Federation, Institute for High Energy Physics, Protvino,Russia
I. Azhgirey, S. Bitioukov, K. Datsko, V. Grishin , V. Kachanov, D. Konstantinov, V. Krychkine,V. Petrov, R. Ryutin, S. Slabospitsky, A. Sobol, A. Sytine, 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. Djordjevic, D. Krpic , D. Maletic, J. Milosevic, J. Puzovic Centro de Investigaciones Energ´eticas Medioambientales y Tecnol ´ogicas (CIEMAT),Madrid, Spain
M. Aguilar-Benitez, J. Alcaraz Maestre, P. Arce, C. Battilana, E. Calvo, M. Cepeda, M. Cerrada,M. Chamizo Llatas, N. Colino, B. De La Cruz, C. Diez Pardos, C. Fernandez Bedoya,J.P. Fern´andez Ramos, A. Ferrando, J. Flix, M.C. Fouz, P. Garcia-Abia, O. Gonzalez Lopez,S. Goy Lopez, J.M. Hernandez, M.I. Josa, G. Merino, J. Puerta Pelayo, I. Redondo, L. Romero,J. Santaolalla, C. Willmott
Universidad Aut ´onoma de Madrid, Madrid, Spain
C. Albajar, J.F. de Troc ´oniz A The CMS Collaboration
Universidad de Oviedo, Oviedo, Spain
J. Cuevas, J. Fernandez Menendez, I. Gonzalez Caballero, L. Lloret Iglesias, J.M. Vizan Garcia
Instituto de F´ısica de Cantabria (IFCA), CSIC-Universidad de Cantabria, Santander, Spain
I.J. Cabrillo, A. Calderon, S.H. Chuang, I. Diaz Merino, C. Diez Gonzalez, J. DuarteCampderros, M. Fernandez, G. Gomez, J. Gonzalez Sanchez, R. Gonzalez Suarez, C. Jorda,P. Lobelle Pardo, A. Lopez Virto, J. Marco, R. Marco, C. Martinez Rivero, P. Martinez Ruiz delArbol, F. Matorras, T. Rodrigo, A. Ruiz Jimeno, L. Scodellaro, M. Sobron Sanudo, I. Vila, R. VilarCortabitarte
CERN, European Organization for Nuclear Research, Geneva, Switzerland
D. Abbaneo, E. Auffray, P. Baillon, A.H. Ball, D. Barney, F. Beaudette , A.J. Bell , D. Benedetti,C. Bernet , W. Bialas, P. Bloch, A. Bocci, S. Bolognesi, H. Breuker, G. Brona, K. Bunkowski,T. Camporesi, E. Cano, A. Cattai, G. Cerminara, T. Christiansen, J.A. Coarasa Perez,R. Covarelli, B. Cur´e, T. Dahms, A. De Roeck, A. Elliott-Peisert, W. Funk, A. Gaddi, S. Gennai,H. Gerwig, D. Gigi, K. Gill, D. Giordano, F. Glege, R. Gomez-Reino Garrido, S. Gowdy,L. Guiducci, M. Hansen, C. Hartl, J. Harvey, B. Hegner, C. Henderson, H.F. Hoffmann,A. Honma, V. Innocente, P. Janot, P. Lecoq, C. Leonidopoulos, C. Lourenc¸o, A. Macpherson,T. M¨aki, L. Malgeri, M. Mannelli, L. Masetti, G. Mavromanolakis, F. Meijers, S. Mersi, E. Meschi,R. Moser, M.U. Mozer, M. Mulders, E. Nesvold , L. Orsini, E. Perez, A. Petrilli, A. Pfeiffer,M. Pierini, M. Pimi¨a, A. Racz, G. Rolandi , C. Rovelli , M. Rovere, H. Sakulin, C. Sch¨afer,C. Schwick, I. Segoni, A. Sharma, P. Siegrist, M. Simon, P. Sphicas , D. Spiga, M. Spiropulu ,F. St ¨ockli, M. Stoye, P. Tropea, A. Tsirou, G.I. Veres , P. Vichoudis, M. Voutilainen, W.D. Zeuner Paul Scherrer Institut, Villigen, Switzerland
W. Bertl, K. Deiters, W. Erdmann, K. Gabathuler, R. Horisberger, Q. Ingram, H.C. Kaestli,S. K ¨onig, D. Kotlinski, U. Langenegger, F. Meier, D. Renker, T. Rohe, J. Sibille ,A. Starodumov Institute for Particle Physics, ETH Zurich, Zurich, Switzerland
L. Caminada , Z. Chen, S. Cittolin, G. Dissertori, M. Dittmar, J. Eugster, K. Freudenreich,C. Grab, A. Herv´e, W. Hintz, P. Lecomte, W. Lustermann, C. Marchica , P. Meridiani,P. Milenovic , F. Moortgat, A. Nardulli, P. Nef, F. Nessi-Tedaldi, L. Pape, F. Pauss, T. Punz,A. Rizzi, F.J. Ronga, L. Sala, A.K. Sanchez, M.-C. Sawley, D. Schinzel, B. Stieger, L. Tauscher † ,A. Thea, K. Theofilatos, D. Treille, M. Weber, L. Wehrli, J. Weng Universit¨at Z ¨urich, Zurich, Switzerland
C. Amsler, V. Chiochia, S. De Visscher, M. Ivova Rikova, B. Millan Mejias, C. Regenfus,P. Robmann, T. Rommerskirchen, A. Schmidt, D. Tsirigkas, L. Wilke
National Central University, Chung-Li, Taiwan
Y.H. Chang, K.H. Chen, W.T. Chen, A. Go, C.M. Kuo, S.W. Li, W. Lin, M.H. Liu, Y.J. Lu, J.H. Wu,S.S. Yu
National Taiwan University (NTU), Taipei, Taiwan
P. Bartalini, P. Chang, Y.H. Chang, Y.W. Chang, Y. Chao, K.F. Chen, W.-S. Hou, Y. Hsiung,K.Y. Kao, Y.J. Lei, S.W. Lin, R.-S. Lu, J.G. Shiu, Y.M. Tzeng, K. Ueno, C.C. Wang, M. Wang,J.T. Wei
Cukurova University, Adana, Turkey
A. Adiguzel, A. Ayhan, M.N. Bakirci, S. Cerci , Z. Demir, C. Dozen, I. Dumanoglu, E. Eskut,S. Girgis, G. G ¨okbulut, Y. G ¨uler, E. Gurpinar, I. Hos, E.E. Kangal, T. Karaman, A. Kayis Topaksu, A. Nart, G. ¨Oneng ¨ut, K. Ozdemir, S. Ozturk, A. Polat ¨oz, O. Sahin, O. Sengul, K. Sogut , B. Tali,H. Topakli, D. Uzun, L.N. Vergili, M. Vergili, C. Zorbilmez Middle East Technical University, Physics Department, Ankara, Turkey
I.V. Akin, T. Aliev, S. Bilmis, M. Deniz, H. Gamsizkan, A.M. Guler, K. Ocalan, A. Ozpineci,M. Serin, R. Sever, U.E. Surat, E. Yildirim, M. Zeyrek
Bogazi¸ci University, Department of Physics, Istanbul, Turkey
M. Deliomeroglu, D. Demir , E. G ¨ulmez, A. Halu, B. Isildak, M. Kaya , O. Kaya , M. ¨Ozbek,S. Ozkorucuklu , N. Sonmez National Scientific Center, Kharkov Institute of Physics and Technology, Kharkov, Ukraine
L. Levchuk
University of Bristol, Bristol, United Kingdom
P. Bell, F. Bostock, J.J. Brooke, T.L. Cheng, D. Cussans, R. Frazier, J. Goldstein, M. Hansen,G.P. Heath, H.F. Heath, C. Hill, B. Huckvale, J. Jackson, L. Kreczko, C.K. Mackay, S. Metson,D.M. Newbold , K. Nirunpong, V.J. Smith, S. Ward Rutherford Appleton Laboratory, Didcot, United Kingdom
L. Basso, K.W. Bell, A. Belyaev, C. Brew, R.M. Brown, B. Camanzi, D.J.A. Cockerill,J.A. Coughlan, K. Harder, S. Harper, B.W. Kennedy, E. Olaiya, D. Petyt, B.C. Radburn-Smith,C.H. Shepherd-Themistocleous, I.R. Tomalin, W.J. Womersley, S.D. Worm
Imperial College, University of London, London, United Kingdom
R. Bainbridge, G. Ball, J. Ballin, R. Beuselinck, O. Buchmuller, D. Colling, N. Cripps, M. Cutajar,G. Davies, M. Della Negra, C. Foudas, J. Fulcher, D. Futyan, A. Guneratne Bryer, G. Hall,Z. Hatherell, J. Hays, G. Iles, G. Karapostoli, L. Lyons, A.-M. Magnan, J. Marrouche, R. Nandi,J. Nash, A. Nikitenko , A. Papageorgiou, M. Pesaresi, K. Petridis, M. Pioppi , D.M. Raymond,N. Rompotis, A. Rose, M.J. Ryan, C. Seez, P. Sharp, A. Sparrow, A. Tapper, S. Tourneur,M. Vazquez Acosta, T. Virdee , S. Wakefield, D. Wardrope, T. Whyntie Brunel University, Uxbridge, United Kingdom
M. Barrett, M. Chadwick, J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, D. Leslie, I.D. Reid,L. Teodorescu
Boston University, Boston, USA
T. Bose, E. Carrera Jarrin, A. Clough, A. Heister, J. St. John, P. Lawson, D. Lazic, J. Rohlf, L. Sulak
Brown University, Providence, USA
J. Andrea, A. Avetisyan, S. Bhattacharya, J.P. Chou, D. Cutts, S. Esen, A. Ferapontov, U. Heintz,S. Jabeen, G. Kukartsev, G. Landsberg, M. Narain, D. Nguyen, T. Speer, K.V. Tsang
University of California, Davis, Davis, USA
M.A. Borgia, R. Breedon, M. Calderon De La Barca Sanchez, D. Cebra, M. Chertok, J. Conway,P.T. Cox, J. Dolen, R. Erbacher, E. Friis, W. Ko, A. Kopecky, R. Lander, H. Liu, S. Maruyama,T. Miceli, M. Nikolic, D. Pellett, J. Robles, T. Schwarz, M. Searle, J. Smith, M. Squires,M. Tripathi, R. Vasquez Sierra, C. Veelken
University of California, Los Angeles, Los Angeles, USA
V. Andreev, K. Arisaka, D. Cline, R. Cousins, A. Deisher, S. Erhan , C. Farrell, M. Felcini,J. Hauser, M. Ignatenko, C. Jarvis, C. Plager, G. Rakness, P. Schlein † , J. Tucker, V. Valuev,R. Wallny A The CMS Collaboration
University of California, Riverside, Riverside, USA
J. Babb, R. Clare, J. Ellison, J.W. Gary, G. Hanson, G.Y. Jeng, S.C. Kao, F. Liu, H. Liu, A. Luthra,H. Nguyen, G. Pasztor , A. Satpathy, B.C. Shen † , R. Stringer, J. Sturdy, S. Sumowidagdo,R. Wilken, S. Wimpenny University of California, San Diego, La Jolla, USA
W. Andrews, J.G. Branson, E. Dusinberre, D. Evans, F. Golf, A. Holzner, R. Kelley,M. Lebourgeois, J. Letts, B. Mangano, J. Muelmenstaedt, S. Padhi, C. Palmer, G. Petrucciani,H. Pi, M. Pieri, R. Ranieri, M. Sani, V. Sharma , S. Simon, Y. Tu, A. Vartak, F. W ¨urthwein,A. Yagil University of California, Santa Barbara, Santa Barbara, USA
D. Barge, R. Bellan, M. Blume, C. Campagnari, M. D’Alfonso, T. Danielson, J. Garberson,J. Incandela, C. Justus, P. Kalavase, S.A. Koay, D. Kovalskyi, V. Krutelyov, J. Lamb, S. Lowette,V. Pavlunin, F. Rebassoo, J. Ribnik, J. Richman, R. Rossin, D. Stuart, W. To, J.R. Vlimant,M. Witherell
California Institute of Technology, Pasadena, USA
A. Bornheim, J. Bunn, M. Gataullin, D. Kcira, V. Litvine, Y. Ma, H.B. Newman, C. Rogan,K. Shin, V. Timciuc, P. Traczyk, J. Veverka, R. Wilkinson, Y. Yang, R.Y. Zhu
Carnegie Mellon University, Pittsburgh, USA
B. Akgun, R. Carroll, T. Ferguson, D.W. Jang, S.Y. Jun, Y.F. Liu, M. Paulini, J. Russ, N. Terentyev,H. Vogel, I. Vorobiev
University of Colorado at Boulder, Boulder, USA
J.P. Cumalat, M.E. Dinardo, B.R. Drell, C.J. Edelmaier, W.T. Ford, B. Heyburn, E. Luiggi Lopez,U. Nauenberg, J.G. Smith, K. Stenson, K.A. Ulmer, S.R. Wagner, S.L. Zang
Cornell University, Ithaca, USA
L. Agostino, J. Alexander, F. Blekman, A. Chatterjee, S. Das, N. Eggert, L.J. Fields, L.K. Gibbons,B. Heltsley, W. Hopkins, A. Khukhunaishvili, B. Kreis, V. Kuznetsov, G. Nicolas Kaufman,J.R. Patterson, D. Puigh, D. Riley, A. Ryd, M. Saelim, X. Shi, W. Sun, W.D. Teo, J. Thom,J. Thompson, J. Vaughan, Y. Weng, P. Wittich
Fairfield University, Fairfield, USA
A. Biselli, G. Cirino, D. Winn
Fermi National Accelerator Laboratory, Batavia, USA
S. Abdullin, M. Albrow, J. Anderson, G. Apollinari, M. Atac, J.A. Bakken, S. Banerjee,L.A.T. Bauerdick, A. Beretvas, J. Berryhill, P.C. Bhat, I. Bloch, F. Borcherding, K. Burkett,J.N. Butler, V. Chetluru, H.W.K. Cheung, F. Chlebana, S. Cihangir, M. Demarteau, D.P. Eartly,V.D. Elvira, I. Fisk, J. Freeman, Y. Gao, E. Gottschalk, D. Green, O. Gutsche, A. Hahn,J. Hanlon, R.M. Harris, J. Hirschauer, E. James, H. Jensen, M. Johnson, U. Joshi, R. Khatiwada,B. Kilminster, B. Klima, K. Kousouris, S. Kunori, S. Kwan, P. Limon, R. Lipton, J. Lykken,K. Maeshima, J.M. Marraffino, D. Mason, P. McBride, T. McCauley, T. Miao, K. Mishra,S. Mrenna, Y. Musienko , C. Newman-Holmes, V. O’Dell, S. Popescu, R. Pordes, O. Prokofyev,N. Saoulidou, E. Sexton-Kennedy, S. Sharma, R.P. Smith † , A. Soha, W.J. Spalding, L. Spiegel,P. Tan, L. Taylor, S. Tkaczyk, L. Uplegger, E.W. Vaandering, R. Vidal, J. Whitmore, W. Wu,F. Yumiceva, J.C. Yun University of Florida, Gainesville, USA
D. Acosta, P. Avery, D. Bourilkov, M. Chen, G.P. Di Giovanni, D. Dobur, A. Drozdetskiy,R.D. Field, Y. Fu, I.K. Furic, J. Gartner, B. Kim, S. Klimenko, J. Konigsberg, A. Korytov, K. Kotov, A. Kropivnitskaya, T. Kypreos, K. Matchev, G. Mitselmakher, L. Muniz, Y. Pakhotin, J. PiedraGomez, C. Prescott, R. Remington, M. Schmitt, B. Scurlock, P. Sellers, D. Wang, J. Yelton,M. Zakaria
Florida International University, Miami, USA
C. Ceron, V. Gaultney, L. Kramer, L.M. Lebolo, S. Linn, P. Markowitz, G. Martinez, D. Mesa,J.L. Rodriguez
Florida State University, Tallahassee, USA
T. Adams, A. Askew, J. Chen, B. Diamond, S.V. Gleyzer, J. Haas, S. Hagopian, V. Hagopian,M. Jenkins, K.F. Johnson, H. Prosper, S. Sekmen, V. Veeraraghavan
Florida Institute of Technology, Melbourne, USA
M.M. Baarmand, S. Guragain, M. Hohlmann, H. Kalakhety, H. Mermerkaya, R. Ralich,I. Vodopiyanov
University of Illinois at Chicago (UIC), Chicago, USA
M.R. Adams, I.M. Anghel, L. Apanasevich, V.E. Bazterra, R.R. Betts, J. Callner, R. Cavanaugh,C. Dragoiu, E.J. Garcia-Solis, C.E. Gerber, D.J. Hofman, S. Khalatian, F. Lacroix, E. Shabalina,A. Smoron, D. Strom, N. Varelas
The University of Iowa, Iowa City, USA
U. Akgun, E.A. Albayrak, B. Bilki, K. Cankocak , W. Clarida, F. Duru, C.K. Lae, E. McCliment,J.-P. Merlo, A. Mestvirishvili, A. Moeller, J. Nachtman, C.R. Newsom, E. Norbeck, J. Olson,Y. Onel, F. Ozok, S. Sen, J. Wetzel, T. Yetkin, K. Yi Johns Hopkins University, Baltimore, USA
B.A. Barnett, B. Blumenfeld, A. Bonato, C. Eskew, D. Fehling, G. Giurgiu, A.V. Gritsan, Z.J. Guo,G. Hu, P. Maksimovic, S. Rappoccio, M. Swartz, N.V. Tran, A. Whitbeck
The University of Kansas, Lawrence, USA
P. Baringer, A. Bean, G. Benelli, O. Grachov, M. Murray, V. Radicci, S. Sanders, J.S. Wood,V. Zhukova
Kansas State University, Manhattan, USA
D. Bandurin, T. Bolton, I. Chakaberia, A. Ivanov, K. Kaadze, Y. Maravin, S. Shrestha,I. Svintradze, Z. Wan
Lawrence Livermore National Laboratory, Livermore, USA
J. Gronberg, D. Lange, D. Wright
University of Maryland, College Park, USA
A. Baden, M. Boutemeur, S.C. Eno, D. Ferencek, N.J. Hadley, R.G. Kellogg, M. Kirn,A.C. Mignerey, K. Rossato, P. Rumerio, F. Santanastasio, A. Skuja, J. Temple, M.B. Tonjes,S.C. Tonwar, E. Twedt
Massachusetts Institute of Technology, Cambridge, USA
B. Alver, G. Bauer, J. Bendavid, W. Busza, E. Butz, I.A. Cali, M. Chan, D. D’Enterria, P. Everaerts,G. Gomez Ceballos, M. Goncharov, K.A. Hahn, P. Harris, Y. Kim, M. Klute, Y.-J. Lee, W. Li,C. Loizides, P.D. Luckey, T. Ma, S. Nahn, C. Paus, C. Roland, G. Roland, M. Rudolph,G.S.F. Stephans, K. Sumorok, K. Sung, E.A. Wenger, B. Wyslouch, S. Xie, Y. Yilmaz, A.S. Yoon,M. Zanetti A The CMS Collaboration
University of Minnesota, Minneapolis, USA
P. Cole, S.I. Cooper, P. Cushman, B. Dahmes, A. De Benedetti, P.R. Dudero, G. Franzoni,J. Haupt, K. Klapoetke, Y. Kubota, J. Mans, V. Rekovic, R. Rusack, M. Sasseville, A. Singovsky
University of Mississippi, University, USA
L.M. Cremaldi, R. Godang, R. Kroeger, L. Perera, R. Rahmat, D.A. Sanders, P. Sonnek,D. Summers
University of Nebraska-Lincoln, Lincoln, USA
K. Bloom, S. Bose, J. Butt, D.R. Claes, A. Dominguez, M. Eads, J. Keller, T. Kelly, I. Kravchenko,J. Lazo-Flores, C. Lundstedt, H. Malbouisson, S. Malik, G.R. Snow
State University of New York at Buffalo, Buffalo, USA
U. Baur, I. Iashvili, A. Kharchilava, A. Kumar, K. Smith, J. Zennamo
Northeastern University, Boston, USA
G. Alverson, E. Barberis, D. Baumgartel, O. Boeriu, S. Reucroft, J. Swain, D. Wood, J. Zhang
Northwestern University, Evanston, USA
A. Anastassov, A. Kubik, R.A. Ofierzynski, A. Pozdnyakov, M. Schmitt, S. Stoynev, M. Velasco,S. Won
University of Notre Dame, Notre Dame, USA
L. Antonelli, D. Berry, M. Hildreth, C. Jessop, D.J. Karmgard, J. Kolb, T. Kolberg, K. Lannon,S. Lynch, N. Marinelli, D.M. Morse, R. Ruchti, J. Slaunwhite, N. Valls, J. Warchol, M. Wayne,J. Ziegler
The Ohio State University, Columbus, USA
B. Bylsma, L.S. Durkin, J. Gu, P. Killewald, T.Y. Ling, M. Rodenburg, G. Williams
Princeton University, Princeton, USA
N. Adam, E. Berry, P. Elmer, D. Gerbaudo, V. Halyo, A. Hunt, J. Jones, E. Laird, D. Lopes Pegna,D. Marlow, T. Medvedeva, M. Mooney, J. Olsen, P. Pirou´e, D. Stickland, C. Tully, J.S. Werner,A. Zuranski
University of Puerto Rico, Mayaguez, USA
J.G. Acosta, X.T. Huang, A. Lopez, H. Mendez, S. Oliveros, J.E. Ramirez Vargas,A. Zatzerklyaniy
Purdue University, West Lafayette, USA
E. Alagoz, V.E. Barnes, G. Bolla, L. Borrello, D. Bortoletto, A. Everett, A.F. Garfinkel, Z. Gecse,L. Gutay, M. Jones, O. Koybasi, A.T. Laasanen, N. Leonardo, C. Liu, V. Maroussov, P. Merkel,D.H. Miller, N. Neumeister, K. Potamianos, I. Shipsey, D. Silvers, H.D. Yoo, J. Zablocki,Y. Zheng
Purdue University Calumet, Hammond, USA
P. Jindal, N. Parashar
Rice University, Houston, USA
V. Cuplov, K.M. Ecklund, F.J.M. Geurts, J.H. Liu, J. Morales, B.P. Padley, R. Redjimi, J. Roberts
University of Rochester, Rochester, USA
B. Betchart, A. Bodek, Y.S. Chung, P. de Barbaro, R. Demina, H. Flacher, A. Garcia-Bellido,Y. Gotra, J. Han, A. Harel, D.C. Miner, D. Orbaker, G. Petrillo, D. Vishnevskiy, M. Zielinski The Rockefeller University, New York, USA
A. Bhatti, L. Demortier, K. Goulianos, K. Hatakeyama, G. Lungu, C. Mesropian, M. Yan
Rutgers, the State University of New Jersey, Piscataway, USA
O. Atramentov, Y. Gershtein, R. Gray, E. Halkiadakis, D. Hidas, D. Hits, A. Lath, K. Rose,S. Schnetzer, S. Somalwar, R. Stone, S. Thomas
University of Tennessee, Knoxville, USA
G. Cerizza, M. Hollingsworth, S. Spanier, Z.C. Yang, A. York
Texas A&M University, College Station, USA
J. Asaadi, R. Eusebi, J. Gilmore, A. Gurrola, T. Kamon, V. Khotilovich, R. Montalvo,C.N. Nguyen, J. Pivarski, A. Safonov, S. Sengupta, D. Toback, M. Weinberger
Texas Tech University, Lubbock, USA
N. Akchurin, C. Bardak, J. Damgov, C. Jeong, K. Kovitanggoon, S.W. Lee, P. Mane, Y. Roh,A. Sill, I. Volobouev, R. Wigmans, E. Yazgan
Vanderbilt University, Nashville, USA
E. Appelt, E. Brownson, D. Engh, C. Florez, W. Gabella, W. Johns, P. Kurt, C. Maguire, A. Melo,P. Sheldon, J. Velkovska
University of Virginia, Charlottesville, USA
M.W. Arenton, M. Balazs, S. Boutle, M. Buehler, S. Conetti, B. Cox, R. Hirosky, A. Ledovskoy,C. Neu, R. Yohay
Wayne State University, Detroit, USA
S. Gollapinni, K. Gunthoti, R. Harr, P.E. Karchin, M. Mattson, C. Milst`ene, A. Sakharov
University of Wisconsin, Madison, USA