Elliptic flow of charm and strange hadrons in high-multiplicity $p+Pb$ collisions at $\sqrt{^s{NN}} = 8.16 TeV$

Abstract

he elliptic azimuthal anisotropy coefficient $(v2)$ is measured for charm $(D^0)$ and strange $(K0S _{0}^{s}$,$Λ$, $Ξ^−$, and $Ω^−$) hadrons, using a data sample of $p+Pb$ collisions collected by the CMS experiment, at a nucleon-nucleon center-of-mass energy of √sNN=8.16  TeV. A significant positive v2 signal from long-range azimuthal correlations is observed for all particle species in high-multiplicity p+Pb collisions. The measurement represents the first observation of possible long-range collectivity for open heavy flavor hadrons in small systems. The results suggest that charm quarks have a smaller $v2$ than the lighter quarks, probably reflecting a weaker collective behavior. This effect is not seen in the larger PbPb collision system at $\sqrt{s_{NN}}=5.02  TeV$, also presented.