Elliptic flow of electrons from heavy-flavour hadron decays at mid-rapidity in Pb–Pb collisions at $\sqrt{s_{\rm NN}}= 2.76$ TeV
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2016-09Author
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The elliptic flow of electrons from heavy-flavour hadron decays at mid-rapidity ($|y| < 0.7$) is measured in Pb–Pb collisions at $\sqrt{s_{\rm NN}}= 2.76$ TeV with ALICE at the LHC. The particle azimuthal distribution with respect to the reaction plane can be parametrized with a Fourier expansion, where the second coefficient ($v_2$) represents the elliptic flow. The $v_2$ coefficient of inclusive electrons is measured in three centrality classes (0–10%, 10–20% and 20–40%) with the event plane and the scalar product methods in the transverse momentum ($p_{\rm T}$) intervals 0.5-13 GeV/$c$ and 0.5-8 GeV/$c$, respectively. After subtracting the background, mainly from photon conversions and Dalitz decays of neutral mesons, a positive $v_2$ of electrons from heavy-flavour hadron decays is observed in all centrality classes, with a maximum significance of $5.9\sigma$ in the interval $2 < p_{\rm T} < 2.5$ GeV/$c$ in semicentral collisions (20–40%). The value of $v_2$ decreases towards more central collisions at low and intermediate $p_{\rm T}$ ($0.5 < p_{\rm T} < 3$ GeV/$c$). The $v_2$ of electrons from heavy-flavour hadron decays at mid-rapidity is found to be similar to the one of muons from heavy-flavour hadron decays at forward rapidity ($2.5 < y < 4$). The results are described within uncertainties by model calculations including substantial elastic interactions of heavy quarks with an expanding strongly-interacting medium.
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Adam J, Adamová D, Aggarwal MM, Aglieri Rinella G, Agnello M, Agrawal N, Ahammed Z, Ahmad SF, Ahn SU, Aiola S, Alme J, Helstrup H, Hetland KF, Kileng B, Altinpinar S, Djuvsland Ø, Lønne P, Nystrand J, Rehman Au, Røhrich D, Tambave GJ, Ullaland K, Velure A, Wagner B, Zhang H, Zhou Z, Zhu H, Arsene IC, Bätzing P, Dordic O, Lindal S, Mahmood SM, Milosevic J, Qvigstad H, Richter M, Røed K, Skaali TB, Tveter TS, Wikne JC, Zhao C, Langøy R, Lien JA, Akindinov A, Alam SN, De Albuquerque DS, Aleksandrov D, Alessandro B, Alexandre D, Alfaro Molina JR, Alici A, Alkin A, Alt T, ALICE C. Elliptic flow of electrons from heavy-flavour hadron decays at mid-rapidity in Pb-Pb collisions at √sNN=2.76 TeV. Journal of High Energy Physics (JHEP). 2016;2016:28Publisher
SpringerSubject
Heavy Ion ExperimentsCollections
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