Pseudorapidity distributions of charged particles in pp collisions at √s = 7 TeV and 0.9 TeV with at least one central charged particle

CMS-PAS-QCD-10-024 in CDS

Abstract

We present a measurements of the charged particle pseudorapidity density distributions in proton-proton collisions at √s = 7 TeV and 0.9 TeV, for particles with a transverse momentum above 0.5 and 1.0 GeV/c and pseudorapidity |η| < 2.4. Only events with at least one charged particle in the kinematic range of |η| < 0.8 or 2.4 are used in the analysis. The measured pseudorapidity distributions using these selections should correspond to inclusive-inelastic distributions, that can be used reliably to improve physics generators of minimum bias events. The data were collected with a minimum-bias trigger during the 2010 Large Hadron Collider (LHC) commissioning period. The events are reconstructed using the inner tracking system of the Compact Muons Solenoid (CMS) detector.

Results for √s=7 TeV

pT > 0.5 GeV particles pT > 1 GeV particles description
08a.png 08b.png Measurement of the normalized charged particle pseudorapidity density distribution, at 7 TeV. Require at least one central track, \η\ < 0.8, and pT > 0.5 GeV/c (left) or > 1 Gev/c (right) -- Nev. Consider only particles with pT > 0.5 GeV/c (left) or > 1 Gev/c (right) in the distributions.
08b.png 08b.png Measurement of the normalized charged particle pseudorapidity density distribution, at 7 TeV. Require at least one track in \η\ < 2.4 and pT > 0.5 GeV/c (left) or > 1 Gev/c (right) -- Nev. Consider only particles with pT > 0.5 GeV/c (left) or > 1 Gev/c (right) in the distributions.

Results for √s=0.9 TeV

pT > 0.5 GeV particles pT > 1 GeV particles description
09b.png 09b.png Measurement of the normalized charged particle pseudorapidity density distribution, at 0.9 TeV. Require at least one central track, \η\ < 0.8, and pT > 0.5 GeV/c (left) or > 1 Gev/c (right) -- Nev. Consider only particles with pT > 0.5 GeV/c (left) or > 1 Gev/c (right) in the distributions.
09b.png 09b.png Measurement of the normalized charged particle pseudorapidity density distribution, at 0.9 TeV. Require at least one track in \η\ < 0.8 and pT > 0.5 GeV/c (left) or > 1 Gev/c (right) -- Nev. Consider only particles with pT > 0.5 GeV/c (left) or > 1 Gev/c (right) in the distributions.

See also

  • MB & UE WG common plots - Minimum Bias and Underlying Event Working Group page. CMS, Atlas and Alice results combined. Some plots below:

pT > 0.5 GeV particles pT > 1 GeV particles description
dndeta_commonplots_Pt500Eta08_Mb7TeV.png dndeta_commonplots_Pt1000Eta08_Mb7TeV.png Combined results from CMS, Atlas and Alice for 7 TeV. pT > 0.5 GeV/c (left) and pT > 1 Gev/c (right). Note: only central region, \η\<0.8 is shown.
dndeta_commonPlots_Pt500Eta08_Mb900GeV.png dndeta_commonPlots_Pt1000Eta08_Mb900GeV.png Combined results from CMS, Atlas and Alice for 0.9 TeV. pT > 0.5 GeV/c (left) and pT > 1 Gev/c (right). Note: only central region, \η\<0.8 is shown.

For CERN users.
  • The root files with the numbers for this analysis are located here:
/afs/cern.ch/user/a/andrey/public/dndeta/update

There are two root files, for 7TeV and 0.9TeV. The TGraphs are stored there together with plot.C macro that helps to print out the numbers.

A note on pythia 8 tune.
Is seems like the tune that was used in that pythia 8: Tune:pp = 2 (aka "Tune 1", default in 8.127 - 8.139 versions).

-- AndreyPozdnyakov - 28-Apr-2011

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng 08a.png r1 manage 43.4 K 2011-06-19 - 15:38 AndreyPozdnyakov  
PNGpng 08b.png r1 manage 51.8 K 2011-06-19 - 15:39 AndreyPozdnyakov  
PNGpng 08c.png r1 manage 42.8 K 2011-06-19 - 15:39 AndreyPozdnyakov  
PNGpng 08d.png r1 manage 45.5 K 2011-06-19 - 15:39 AndreyPozdnyakov  
PNGpng 09a.png r1 manage 40.8 K 2011-06-19 - 15:40 AndreyPozdnyakov  
PNGpng 09b.png r1 manage 42.8 K 2011-06-19 - 15:40 AndreyPozdnyakov  
PNGpng 09c.png r1 manage 35.4 K 2011-06-19 - 15:40 AndreyPozdnyakov  
PNGpng 09d.png r1 manage 38.2 K 2011-06-19 - 15:40 AndreyPozdnyakov  
PNGpng comp_dndeta.png r1 manage 18.1 K 2011-06-24 - 15:32 AndreyPozdnyakov  
PNGpng dndeta_commonPlots_Pt1000Eta08_Mb900GeV.png r1 manage 24.6 K 2011-06-24 - 15:54 AndreyPozdnyakov  
PNGpng dndeta_commonPlots_Pt500Eta08_Mb900GeV.png r1 manage 23.5 K 2011-06-24 - 15:54 AndreyPozdnyakov  
PNGpng dndeta_commonplots_Pt1000Eta08_Mb7TeV.png r1 manage 22.6 K 2011-06-24 - 15:32 AndreyPozdnyakov  
PNGpng dndeta_commonplots_Pt500Eta08_Mb7TeV.png r1 manage 22.6 K 2011-06-24 - 15:32 AndreyPozdnyakov  
PNGpng dndeta_fulleta_Pt500_Mb7TeV.png r1 manage 22.5 K 2011-06-24 - 15:54 AndreyPozdnyakov  
PNGpng dndeta_fulleta_Pt500_Mb900GeV.png r1 manage 22.0 K 2011-06-24 - 15:55 AndreyPozdnyakov  
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Topic revision: r8 - 2013-06-18 - AndreyPozdnyakov
 
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