Probing the profile of bulk matter in p+Pb collisions via directed flow of heavy quarks

Abstract

The asymmetric initial geometry in p+Pb collisions provide an opportunity to probe the initial matter distribution in these collisions. Using A Multi-Phase Transport (AMPT) model, we have studied the production of light and heavy quark particles in p+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. The pseudo-rapidity density (dN/d$\eta$) and elliptic flow ($v_2$) of light-quark particles from AMPT reasonably agrees with the measurements by ALICE. We predicted the directed flow of light and heavy quarks in p+Pb collisions. The $v_1$ of both light and heavy-quark mesons show a non-trivial $p_T$ dependence in p- and Pb-going directions. When integrated over the transverse momentum range 0 $<p_T<$5 GeV/c, the magnitude of heavy quark directed flow ($v_1$) is found to be 15 times larger than the light quark species in the Pb-going direction while the same in the p-going direction are comparable. The light and heavy quarks $v_1$ may offer the possibility to probe the initial matter density as well as the collective dynamics in p+Pb collisions

Comments: 7 pages, 9 figures