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.

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 Single10Feb_FINAL.png r1 manage 41.0 K 2014-07-09 - 16:38 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 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 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
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Topic revision: r4 - 2014-07-09 - JonathanHollar
 
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