Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV

0488723 - ÚJF 2019 RIV NL eng J - Journal Article
Acharya, S. - Adamová, Dagmar - Bielčík, J. - Bielčíková, Jana - Broz, M. - Contreras, J. G. - Hladký, Jan - Horák, D. - Křížek, Filip - Kučera, Vít - Kushpil, Svetlana - Lavička, R. - Mareš, Jiří A. - Petráček, V. - Šumbera, Michal - Vaňát, Tomáš - Závada, Petr … Total 1031 authors
Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV.
Physics Letters. B. Roč. 777, č. 2 (2018), s. 151-162. ISSN 0370-2693. E-ISSN 1873-2445
R&D Projects: GA MŠMT(CZ) LG15052
Institutional support: RVO:61389005 ; RVO:68378271
Keywords : ALICE * heavy ion collisions * relativistic nuclear collisions
OECD category: Nuclear physics; Particles and field physics (FZU-D)
Impact factor: 4.162, year: 2018

In ultrarelativistic heavy-ion collisions, the event-by-event variation of the elliptic flow v(2) reflects fluctuations in the shape of the initial state of the system. This allows to select events with the same centrality but different initial geometry. This selection technique, Event Shape Engineering, has been used in the analysis of charge-dependent two-and three-particle correlations in Pb-Pb collisions at root s(NN) = 2.76 TeV. The two-particle correlator < cos(phi(alpha) - phi(ss))>, calculated for different combinations of charges alpha and beta, is almost independent of v(2) (for a given centrality), while the three-particle correlator < cos(phi(alpha) + phi(beta) - 2 Psi(2))> scales almost linearly both with the event v(2) and charged-particle pseudorapidity density. The charge dependence of the three-particle correlator is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity violating effect of the strong interaction. However, its measured dependence on v(2) points to a large non-CME contribution to the correlator. Comparing the results with Monte Carlo calculations including a magnetic field due to the spectators, the upper limit of the CME signal contribution to the three-particle correlator in the 10-50% centrality interval is found to be 26-33% at 95% confidence level.
Permanent Link: http://hdl.handle.net/11104/0283265