Anisotropic flow of identified particles in Pb-Pb collisions at $$ {\sqrt{s}}_{\mathrm{NN}}=5.02 $$ TeV

Abstract

The elliptic (v 2 ), triangular (v 3 ), and quadrangular (v 4 ) flow coefficients of π ± , K ± , p + p, Λ + Λ, K 0 S , and the φ-meson are measured in Pb-Pb collisions at √ s NN = 5.02 TeV. Results obtained with the scalar product method are reported for the rapidity range |y| < 0.5 as a function of transverse momentum, p T , at different collision centrality intervals between 0-70%, including ultra-central (0-1%

Study of J/ψ azimuthal anisotropy at forward rapidity in Pb-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}}=5.02 $$ TeV

“…The position of the maximum, divided by the number of constituent quarks n q , does not dependent strongly on the particle mass as predicted by coalescence models [28]. Furthermore, the v n values at the maximum, divided by n q , are similar for all measured light-flavoured particles, with deviations of up to ±20% between mesons and baryons [27]. At high p T above 6-8 GeV/c, the observed azimuthal anisotropy of the final-state particles is believed to come from path-length dependent parton energy loss inside the QGP.…”

“…Thus, the data seem to suggest an ordering similar to the one observed for the v 2 and v 3 coefficients in semi-central collisions. It is interesting to note that, in contrast, the mass ordering of v 2 and v 3 seen for light-flavored particles is strongly suppressed in the ratio v 3 /v 2 [27].…”

“…The parameters κ n encode the response of the QGP medium and depend on the particle type and mass as well as its transverse momentum. At low p T , the flow coefficients of light-flavoured particles increase with increasing p T [26,27]. This increase of v n coefficients as a function of p T depends of the particle mass and can be attributed to the radial expansion of the QGP medium.…”

“…Nevertheless, the correlation between the flow coefficients and the initial-state eccentricities is weaker with respect to the hydrodynamic case, especially between v 3 and 3 . Interestingly, the particle-mass dependence of v 2 and v 3 appears to be strongly reduced in the ratio v 3 /v 2 in semi-central collisions for light-flavored particles [27]. Whether the above considerations also hold for heavy quarks and quarkonia is an open question whose answer could help to understand the origin of charm quark azimuthal anisotropies and characterize their interactions with the flowing medium.…”

Global polarization of Λ and Λ¯ hyperons in Pb-Pb collisions at sNNAcharya1, Antičić2, Erhardt3 et al. 2020Phys. Rev. CSelf Cite901350View full textAdd to dashboardCite

“…The and hyperons were reconstructed via their weak decay topology following the method and selection criteria described in Refs. [28,40]. Charged daughter tracks from hyperon decay were required to have the pseudorapidity |η| < 0.9 and at least 70 space points in the TPC.…”