Measurement of pseudorapidity distributions of charged particles in proton-proton collisions at s√ = 8 TeV by the CMS and TOTEM experiments

Abstract

Pseudorapidity (η) distributions of charged particles produced in proton-proton collisions at a centre-of-mass energy of 8 TeV are measured in the ranges abs(η) < 2.2 and 5.3 < abs(η) < 6.4 covered by the CMS and TOTEM detectors, respectively. The data correspond to an integrated luminosity of 45 inverse microbarns. Measurements are presented for three event categories. The most inclusive category is sensitive to 91-96% of the total inelastic proton-proton cross section. The other two categories are disjoint subsets of the inclusive sample that are either enhanced or depleted in single diffractive dissociation events. The data are compared to models used to describe high-energy hadronic interactions. None of the models considered provide a consistent description of the measured distributions.

Figures

Figure 1

Figure caption: Charged-particle pseudorapidity distributions from an inclusive sample. The error bars represent the statistical + uncorrelated systematics between neighbouring bins and the bands show the combined systematic and statistical uncertainties. The measurements are compared to results from PYTHIA6, tune Z2*, PYTHIA8, tune 4C, HERWIGpp, tune UE-EE-3 with CTEQ6L1 PDFs, EPOS, tune LHC, and QGS-04.

Figure 1

Figure caption: Charged-particle pseudorapidity distributions from a NSD-enhanced sample. The error bars represent the statistical + uncorrelated systematics between neighbouring bins and the bands show the combined systematic and statistical uncertainties. The measurements are compared to results from PYTHIA6, tune Z2*, PYTHIA8, tune 4C, HERWIGpp, tune UE-EE-3 with CTEQ6L1 PDFs, EPOS, tune LHC, and QGS-04.

Figure 1

Figure caption: Charged-particle pseudorapidity distributions from a SD-enhanced sample (bottom). The error bars represent the statistical + uncorrelated systematics between neighbouring bins and the bands show the combined systematic and statistical uncertainties. The measurements are compared to results from PYTHIA6, tune Z2*, PYTHIA8, tune 4C, HERWIGpp, tune UE-EE-3 with CTEQ6L1 PDFs, EPOS, tune LHC, and QGS-04.

Figure 1

Figure caption: Value of dNch/dη at η≈0 as a function of the centre-of-mass energy in p-p and p-pbar collisions. Shown are measurements performed with different NSD event selections from UA1, UA5, CDF, ALICE, and CMS. The dashed line is a power-law fit to the data.

Figure 1

Figure caption: The zimpact parameter distribution for the data tracks reconstructed in one T2 half-arm in the range −5.8<η<−5.75. A global (double-Gaussian + exponential function) fit, performed in the range from −8 to 15m is shown by the solid curve. The dotted curve represents the exponential component from secondary particles, while the dashed curve is the double-Gaussian component, mainly due to primary tracks.

Figure 1

Figure caption: Trigger efficiency as a function of the total track multiplicity in the T2 telescopes for single-sided events with primary candidates in only the z>0 (+) or z<0 (−) telescope and double-sided events with primary candidates in both telescopes.

Figure 1

Figure caption: tracking efficiency, ϵ{trk}, as a function of pT and η and averaged over all multiplicity bins (nCMS), for tracks with pT>0.1 GeVc and abs(η)<2.2.

Figure 1

Correction factor, fnp, for non-primary tracks as a function of pT and η and averaged over all multiplicity bins (nCMS), for tracks with pT>0.1 GeVc and abs(η)<2.2

Figure 1

Figure caption: Primary track efficiency as a function of η and average pad cluster multiplicity (APM) in one T2 half-arm for the inclusive pp sample. The efficiency includes the track primary-candidate condition. Only particles with pT>40\MeVc are considered.

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng Double10Feb_FINAL.png r1 manage 49.2 K 2014-07-09 - 16:38 JonathanHollar  
PNGpng Inclusive10Feb_FINAL.png r1 manage 47.2 K 2014-07-09 - 16:38 JonathanHollar  
PNGpng PrimTrkEffi.png r1 manage 36.2 K 2014-07-11 - 17:16 JonathanHollar  
PNGpng Single10Feb_FINAL.png r1 manage 41.0 K 2014-07-09 - 16:38 JonathanHollar  
PNGpng Trigger_effi16Dec.png r1 manage 17.7 K 2014-07-11 - 17:13 JonathanHollar  
PNGpng ZImpact_cms_22Dic.png r1 manage 22.8 K 2014-07-11 - 17:11 JonathanHollar  
PNGpng cms_double.png r1 manage 23.2 K 2013-04-22 - 23:05 PanagiotisKatsas  
PNGpng cms_inclusive.png r1 manage 23.1 K 2013-04-22 - 22:37 PanagiotisKatsas  
PNGpng combined_double.png r2 r1 manage 29.1 K 2013-04-23 - 09:44 PanagiotisKatsas  
PNGpng combined_inclusive.png r2 r1 manage 26.6 K 2013-04-23 - 09:44 PanagiotisKatsas  
PNGpng fnp_CWR.png r1 manage 16.6 K 2014-07-11 - 17:16 JonathanHollar  
PNGpng pt1000_inclusive.png r1 manage 48.4 K 2013-04-22 - 15:59 PanagiotisKatsas pseudorapidity distributions
PNGpng pt1000_nsd.png r2 r1 manage 48.1 K 2013-04-22 - 22:50 PanagiotisKatsas  
PNGpng pt100_inclusive.png r1 manage 48.3 K 2013-04-22 - 15:59 PanagiotisKatsas pseudorapidity distributions
PNGpng pt100_nsd.png r2 r1 manage 49.8 K 2013-04-22 - 22:52 PanagiotisKatsas  
PNGpng sqrts_vs_dndeta-data.png r3 r2 r1 manage 28.1 K 2013-04-23 - 00:24 PanagiotisKatsas  
PNGpng sqrts_vs_dndeta-data_CWR.png r1 manage 28.0 K 2014-07-09 - 16:38 JonathanHollar  
PNGpng trackEff_CWR_eta22.png r1 manage 16.2 K 2014-07-11 - 17:14 JonathanHollar  
PNGpng track_pt_integrated_corrected_08.png r1 manage 41.2 K 2013-04-22 - 15:44 PanagiotisKatsas leading track pt distributions
PNGpng track_pt_integrated_corrected_08_mc.png r1 manage 39.8 K 2013-04-22 - 15:44 PanagiotisKatsas leading track pt distributions
PNGpng track_pt_leading_08.png r1 manage 47.3 K 2013-04-22 - 15:44 PanagiotisKatsas leading track pt distributions
PNGpng track_pt_leading_08_mc.png r1 manage 46.4 K 2013-04-22 - 15:44 PanagiotisKatsas leading track pt distributions

This topic: CMSPublic > WebPreferences > PhysicsResultsFSQ12026
Topic revision: r5 - 2014-07-11 - JonathanHollar
 
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