Date

Collaboration

Prompt and non-prompt J/psi production in pp collisions at sqrt(s) = 7 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J.C 71 (2011) 1575, 2011.
Inspire Record 878118 DOI 10.17182/hepdata.57532

The production of J/psi mesons is studied in pp collisions at sqrt(s)=7 TeV with the CMS experiment at the LHC. The measurement is based on a dimuon sample corresponding to an integrated luminosity of 314 inverse nanobarns. The J/psi differential cross section is determined, as a function of the J/psi transverse momentum, in three rapidity ranges. A fit to the decay length distribution is used to separate the prompt from the non-prompt (b hadron to J/psi) component. Integrated over J/psi transverse momentum from 6.5 to 30 GeV/c and over rapidity in the range |y| < 2.4, the measured cross sections, times the dimuon decay branching fraction, are 70.9 \pm 2.1 (stat.) \pm 3.0 (syst.) \pm 7.8(luminosity) nb for prompt J/psi mesons assuming unpolarized production and 26.0 \pm 1.4 (stat.) \pm 1.6 (syst.) \pm 2.9 (luminosity) nb for J/psi mesons from b-hadron decays.

13 data tables

Total cross section within the kinematic limits for prompt and non-prompt J/PSI production times branching ratio into MU+ MU-, assuming zero polarizartion. The second systematic error is the luminosity uncertainty.

Differential inclusive cross J/PSI section for the |rapidity| range 0 to 1.2 for each prompt J/PSI polarization scenario considered.

Differential inclusive cross J/PSI section for the |rapidity| range 1.2 to 1.6 for each prompt J/PSI polarization scenario considered.

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Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at sqrt(s) = 7 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M. ; Tumasyan, Armen ; et al.
Phys.Rev.Lett. 105 (2010) 022002, 2010.
Inspire Record 855299 DOI 10.17182/hepdata.56006

Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at sqrt(s) = 7 TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit-pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity, dN(charged)/d(eta), for |eta| < 0.5, of 5.78 +/- 0.01 (stat) +/- 0.23 (syst) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from sqrt(s) = 0.9 to 7 TeV is 66.1% +/- 1.0% (stat) +/- 4.2% (syst). The mean transverse momentum is measured to be 0.545 +/- 0.005 (stat) +/- 0.015 (syst) GeV/c. The results are compared with similar measurements at lower energies.

5 data tables

Measured differential yield of charged hadrons as a function oftransverse momentum for pseudorapidities 0.1, 0.3, 0.5 and 0.7 for centre-of-mass energy 7000 GeV.Errors are statistical and systematic added in quadrature.

Measured differential yield of charged hadrons as a function oftransverse momentum for pseudorapidities 0.9, 1.1, 1.3 and 1.5 for centre-of-mass energy 7000 GeV.Errors are statistical and systematic added in quadrature.

Measured differential yield of charged hadrons as a function oftransverse momentum for pseudorapidities 1.7, 1.9, 2.1 and 2.3 for centre-of-mass energy 7000 GeV.Errors are statistical and systematic added in quadrature.

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Charged-particle multiplicities in pp interactions at sqrt(s) = 900 GeV measured with the ATLAS detector at the LHC

The ATLAS collaboration Aad, G. ; Abat, E. ; Abbott, B. ; et al.
Phys.Lett.B 688 (2010) 21-42, 2010.
Inspire Record 849050 DOI 10.17182/hepdata.54850

The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range |eta|<2.5 and pT>500 MeV. The measurements are compared to Monte Carlo models of proton-proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity at eta = 0 is measured to be 1.333 +/- 0.003 (stat.) +/- 0.040 (syst.), which is 5-15% higher than the Monte Carlo models predict.

5 data tables

Average value of charged particle multiplicity per event and unit of pseudorapidity in the pseudorapidity range from -0.2 to 0.2.

Charged particle multiplicity as a function of pseudorapidity.

Charged particle multiplicity as a function of transverse momentum.

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Measurement of the Underlying Event Activity in Proton-Proton Collisions at 0.9 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M. ; Tumasyan, Armen ; et al.
Eur.Phys.J.C 70 (2010) 555-572, 2010.
Inspire Record 857644 DOI 10.17182/hepdata.55126

A measurement of the underlying activity in scattering processes with transverse momentum scale in the GeV region is performed in proton-proton collisions at sqrt(s) = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged hadron production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged hadrons with pseudorapidity eta < 2, p_T > 0.5 GeV/c, and azimuthal direction transverse to that of the leading object.

7 data tables

Average multiplicity of charged particles per unit of pseudorapidity as a function of pseudorapidity for events with leading track-jet transverse momenta > 1 and > 3 GeV. Statistical errors only.

Average scalar sum of the transverse momenta of charged particles per unit of pseusdorapidity and per radian as a function of DELTA(PHI) for events with leading track-jet transverse momenta > 1 and > 2 GeV. Statistical errors only. Typical systematic error of 1.8 PCT at a leading track-jet PT of 3.5 GeV.

The average multiplicity and average scalar sum of transverse momenta of charge particles per unit of pseudorapidity and per radian as a function of the leading track transverse momenta. Statistical errors only. Typical systematic error of 1.8 PCT at a leading track-jet PT of 3.5 GeV.

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PROPERTIES OF THE C Ta INTERACTIONS WITH LAMBDA HYPERON AND K0 MESON PRODUCTION AT 4.2-GeV/c PER NUCLEON

Iovchev, K. ; Kanarek, T. ; Kladnitskaya, E.N. ; et al.
JINR-P1-84-279, 1984.
Inspire Record 202985 DOI 10.17182/hepdata.17552

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14 data tables

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