Elliptic Flow of Identified Hadrons in Au + Au Collisions at √ˢᴺᴺ = 7.7- 62.4 GeV

Authors

L. Adamczyk
J. K. Adkins
G. Agakishiev
M. M. Aggarwal
S. Bültmann, Old Dominion University
STAR Collaboration

Document Type

Article

Publication Date

2013

DOI

10.1103/PhysRevC.88.014902

Publication Title

Physical Review C

Volume

88

Issue

1

Pages

014902 (1-25)

Abstract

Measurements of the elliptic flow, υ₂, of identified hadrons (π^±, , K^±, , K^O_s, p, p¯, ɸ, 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 midrapidity using the time-projection chamber and the time-of-flight detectors of the Solenoidal Tracker at RHIC experiment during the beam-energy scan program at Relativistic Heavy Ion Collider. A significant difference in the υ₂ values for particles and the corresponding antiparticles 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, μ_B, and is larger for the baryons as compared to the mesons. This implies that particles and antiparticles are no longer consistent with the universal number-of-constituent quark (NCQ) scaling of υ₂ that was observed at √ˢᴺᴺ = 200 GeV. However, for the selected group of particles (π⁺, K⁺, K^O_s, p, Λ, Ξ-, Ω- NCQ scaling at (m_T - m₀/n_q > 0.4 GeV/c²is not violated within ± 10%. The υ₂ values for ɸ 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 p_T values.

Comments

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Original Publication Citation

Adamczyk, L., Adkins, J. K., Agakishiev, G., Aggarwal, M. M., Ahammed, Z., Alekseev, I., . . . Collaboration, S. (2013). Elliptic flow of identified hadrons in Au + Au collisions at √ˢᴺᴺ =7.7-62.4 GeV. Physical Review C, 88(1), 014902 doi:10.1103/PhysRevC.88.014902

Repository Citation

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Bültmann, S.; and STAR Collaboration, "Elliptic Flow of Identified Hadrons in Au + Au Collisions at √ˢᴺᴺ = 7.7- 62.4 GeV" (2013). Physics Faculty Publications. 177.
https://digitalcommons.odu.edu/physics_fac_pubs/177