Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at √s = 7 TeV

Adam, J. and Antičić, Tome and Planinić, Mirko and Poljak, Nikola and Simatović, Goran and Utrobičić, Antonija and Zyzak, M. (ALICE Collaboration) (2015) Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at √s = 7 TeV. Journal of High Energy Physics, 2015 (9). pp. 148-46. ISSN 1029-8479

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Abstract

Prompt D meson and non-prompt J/ψ yields are studied as a function of the multiplicity of charged particles produced in inelastic proton-proton collisions at a centreof-mass energy of √s = 7 TeV. The results are reported as a ratio between yields in a given multiplicity interval normalised to the multiplicity-integrated ones (relative yields). They are shown as a function of the multiplicity of charged particles normalised to the average value for inelastic collisions (relative charged-particle multiplicity). D0 , D+ and D∗+ mesons are measured in five pT intervals from 1 GeV/c to 20 GeV/c and for |y| < 0.5 via their hadronic decays. The D-meson relative yield is found to increase with increasing charged-particle multiplicity. For events with multiplicity six times higher than the average multiplicity of inelastic collisions, a yield enhancement of a factor about 15 relative to the multiplicity-integrated yield in inelastic collisions is observed. The yield enhancement is independent of transverse momentum within the uncertainties of the measurement. The D0 -meson relative yield is also measured as a function of the relative multiplicity at forward pseudo-rapidity. The non-prompt J/ψ, i.e. the B hadron, contribution to the inclusive J/ψ production is measured in the di-electron decay channel at central rapidity. It is evaluated for pT > 1.3 GeV/c and |y| < 0.9, and extrapolated to pT > 0. The fraction of non-prompt J/ψ in the inclusive J/ψ yields shows no dependence on the charged-particle multiplicity at central rapidity. Charm and beauty hadron relative yields exhibit a similar increase with increasing charged-particle multiplicity. The measurements are compared to PYTHIA 8, EPOS 3 and percolation calculations.

Item Type: Article
Keywords: hadron-hadron scattering
Date: September 2015
Subjects: NATURAL SCIENCES > Physics
Additional Information: Open Access. © Copyright CERN, for the benefit of the ALICE Collaboration. Article funded by SCOAP3. Received: May 11, 2015. Revised: June 5, 2015. Accepted: August 10, 2015. Published: September 22, 2015.
Divisions: Faculty of Science > Department of Physics
Publisher: Springer
Depositing User: Nikola Poljak
Date Deposited: 28 May 2016 19:59
Last Modified: 28 May 2016 19:59
URI: http://digre.pmf.unizg.hr/id/eprint/4862

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