Elliptic Flow of Charm and Strange Hadrons in High-Multiplicity p+Pb Collisions at sNN=8.16 

Abstract

The elliptic azimuthal anisotropy coefficient (v_{2}) is measured for charm (D^{0}) and strange (K_{S}^{0}, 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 sqrt[s_{NN}]=8.16 TeV. A significant positive v_{2} 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 v_{2} 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.

Studies of various physics effects on an on-axis LHCD experiment using numerical tools

“…in the pA collisions at the LHC [420,421], although its magnitude is lower than the v 2 of light hadrons. There are also hints of non-zero v 2 of heavy quarks in dAu collisions at √ s NN = 200 GeV at RHIC.…”

Jet quenching as a probe of the initial stages in heavy-ion collisions

“…Furthermore, recent experimental results from the LHC, and later from RHIC, in small system p-Pb, highmultiplicity p-p and d-Au collisions, show characteristics [1] usually attributed to QGP formation. Indeed, usual key probes of the QGP, such as long-range angular correlations and flow harmonics [2][3][4][5][6][7][8][9], and the strangeness enhancement [10] have been observed in small systems. Interestingly, the only long-established QGP signature missing in these experimental data is jet quenching [11].…”

Measurement of B+ , B0 and Λb0 production

“…Measurements sensitive to hadronization fractions in the heavy-flavor sector can contribute to a better understanding. Studies of hadronization in heavy nuclear collisions may help to explain the puzzle of heavy-flavor hadron collective behavior that was observed recently in pp and proton-lead collisions [12][13][14]. These measurements in small collision systems still require a common reconciliation with the global theoretical picture of heavy-ion collisions based on fluid dynamics, or might result in modifications to the fluid-based description.…”