Naslov
Elliptic flow of identified hadrons in Au+Au collisions at $\sqrt{; ; s_{; ; NN}; ; }; ; =$ 7.7--62.4 GeV

Autori
Adamczyk, L. ; ... ; Planinić, Mirko ; ... ; Poljak, Nikola ; ... ; Zyzak, M.

Izvornik
Physical Review C (0556-2813) 88 (2013); 14902-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
elliptic flow; hadrons; AuAu; STAR

Sažetak
Measurements of the elliptic flow, v2, of identified hadrons (π±, K ±, K0s, p, p¯, ϕ, Λ, Λ¯, Ξ−, Ξ¯+, Ω−, Ω¯+) in Au+Au collisions at sNN‾‾‾‾√= 7.7, 11.5, 19.6, 27, 39 and 62.4 GeV are presented. The measurements were done at mid-rapidity using the Time Projection Chamber and the Time-of-Flight detectors of the STAR experiment during the Beam Energy Scan program at RHIC. A significant difference in the v2 values for particles and the corresponding anti-particles was observed at all transverse momenta for the first time. The difference increases with decreasing center-of-mass energy, sNN‾‾‾‾√ (or increasing baryon chemical potential, μB) and is larger for the baryons as compared to the mesons. This implies that particles and anti-particles are no longer consistent with the universal number-of-constituent quark (NCQ) scaling of v2 that was observed at sNN‾‾‾‾√= 200 GeV. However, for the group of particles NCQ scaling at (mT−m0)/nq> 0.4 GeV/c2 is not violated within ±10%. The v2 values for ϕ mesons at 7.7 and 11.5 GeV are approximately two standard deviations from the trend defined by the other hadrons at the highest measured pT values.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
STAR Collaboration.

POVEZANOST RADA