Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at root s(NN)=5.02 TeV

0543059 - ÚJF 2022 RIV US eng J - Journal Article
Acharya, S. - Adamová, Dagmar - Bielčík, J. - Bielčíková, Jana - Broz, M. - Contreras, J. G. - Isakov, Artem - Herman, T. - Horák, D. - Křížek, Filip - Křížková Gajdošová, K. - Kushpil, Svetlana - Lavička, R. - Mareš, Jiří A. - Petráček, V. - Šafařík, K. - Šumbera, Michal - Torres, S. R. - Trzeciak, B. A. - Závada, Petr … Total 1015 authors
Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at root s(NN)=5.02 TeV.
Physical Review Letters. Roč. 126, č. 16 (2021), č. článku 162001. ISSN 0031-9007. E-ISSN 1079-7114
R&D Projects: GA MŠMT(CZ) LTT17018; GA MŠMT(CZ) LM2018104
Research Infrastructure: CERN-CZ II - 90104
Institutional support: RVO:68378271 ; RVO:61389005
Keywords : ALICE collaboration * heavy ion experiment * Beauty-hadron decays
OECD category: Nuclear physics; Particles and field physics (FZU-D)
Impact factor: 9.185, year: 2021
Method of publishing: Limited access
https://doi.org/10.1103/PhysRevLett.126.162001

The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at root s(NN)=5.02  TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v2. The v2 coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (pT) range 1.3–6  GeV/c in the centrality class 30%–50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length ct(approx.) 500 um compared to that of charm hadrons and most of the other background sources. The v2 of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75 Sigma. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high pT, but is in agreement with the results at low pT. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.
Permanent Link: http://hdl.handle.net/11104/0320363