Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 TeV

0501146 - ÚJF 2020 RIV NL eng J - Článek v odborném periodiku
Acharya, S. - Acosta, F. T. - Adamová, Dagmar - Bielčík, J. - Bielčíková, Jana - Broz, M. - Contreras, J. G. - Horák, D. - Křížek, Filip - Kučera, Vít - Kushpil, Svetlana - Mareš, Jiří A. - Petráček, V. - Šumbera, Michal - Závada, Petr … celkem 1009 autorů
Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 TeV.
Physics Letters. B. Roč. 788, č. 1 (2019), s. 505-518. ISSN 0370-2693. E-ISSN 1873-2445
Grant CEP: GA MŠMT(CZ) LTT17018
Výzkumná infrastruktura: CERN-CZ - 90058
Institucionální podpora: RVO:68378271 ; RVO:61389005
Klíčová slova: ALICE collaboration * heavy ion collisions
Obor OECD: Nuclear physics; Particles and field physics (FZU-D)
Impakt faktor: 4.384, rok: 2019
Způsob publikování: Open access
https://doi.org/10.1016/j.physletb.2018.11.009

The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p(T)) at midrapidity (vertical bar ye vertical bar < 0.8) in proton-proton (pp) collisions at a centre-of-mass energy of root s = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at root s = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: d sigma(c<(c)over bar>)/dy vertical bar(y=0) = 974 +/- 138 (stat.) +/- 140 (syst.) +/- 214(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 79 +/- 14 (stat.) +/- 11 (syst.) +/- 5(BR) mu b using PYTHIA simulations and d sigma(c (c) over bar)/dy vertical bar(y=0) = 1417 +/- 184 (stat.) +/- 204 (syst.) +/- 312(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 48 +/- 14 (stat.) +/- 7 (syst.) +/- 3(BR) mu b for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p(T) intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p(T). Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations.
Trvalý link: http://hdl.handle.net/11104/0293184