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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Physics

Old Dominion University

2014

Matter

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Measurement Of Charge Multiplicity Asymmetry Correlations In High-Energy Nucleus-Nucleus Collisions At √ˢᶰᶰ = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, S. Bültmann, Star Collaboration Jan 2014

Measurement Of Charge Multiplicity Asymmetry Correlations In High-Energy Nucleus-Nucleus Collisions At √ˢᶰᶰ = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, S. Bültmann, Star Collaboration

Physics Faculty Publications

A study is reported of the same-and opposite-sign charge-dependent azimuthal correlations with respect to the event plane in Au+ Au collisions at √ˢᶰᶰ = 200 GeV. The charge multiplicity asymmetries between the up/down and left/right hemispheres relative to the event plane are utilized. The contributions from statistical fluctuations and detector effects were subtracted from the (co-) variance of the observed charge multiplicity asymmetries. In the mid-to most-central collisions, the same- (opposite-) sign pairs are preferentially emitted in back-to-back (aligned on the same-side) directions. The charge separation across the event plane, measured by the difference, Δ, between the like-and unlike-sign up/down-left/right …


Dielectron Mass Spectra From Au Plus Au Collisions At √ˢᴺᴺ = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, D. Plyku, Star Collaboration Jan 2014

Dielectron Mass Spectra From Au Plus Au Collisions At √ˢᴺᴺ = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, D. Plyku, Star Collaboration

Physics Faculty Publications

We report the STAR measurements of dielectron (e+e-) production at midrapidity ( |yee| < 1) in Au + Au collisions at √ˢᴺᴺ = 200 GeV. The measurements are evaluated in different invariant mass regions with a focus on 0.30-0.76 (ρ-like), 0.76-0.80 (ω-like), and 0.98-1.05 (ɸ-like) GeV/c2. The spectrum in the ω-like and ɸ-like regions can be well described by the hadronic cocktail simulation. In the ρ-like region, however, the vacuum ρ spectral function cannot describe the shape of the dielectron excess. In this range, an enhancement of 1.77 ±0.11(stat) ± 0.24(syst) ± 0.33(cocktail) is determined with respect to the hadronic cocktail simulation that excludes the ρ meson. The excess yield in the ρ-like region increases with the number of collision participants faster than the ω …


J/Ψ Production At Low Pᵀ In Au + Au And Cu + Cu Collisions At √ˢᴺᴺ = 200 Gev With The Star Detector, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, I. Koralt, Star Collaboration Jan 2014

J/Ψ Production At Low Pᵀ In Au + Au And Cu + Cu Collisions At √ˢᴺᴺ = 200 Gev With The Star Detector, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, I. Koralt, Star Collaboration

Physics Faculty Publications

The J/ψ pT spectrum and nuclear modification factor (RAA) are reported for pT < 5 GeV/c and |y| < 1 from 0% to 60% central Au + Au and Cu + Cu collisions at √ˢᴺᴺ = 200 GeV at STAR. A significant suppression of pT - integrated J/ψ production is observed in central Au + Au events. The Cu + Cu data are consistent with no suppression, although the precision is limited by the available statistics. RAA in Au + Au collisions exhibits a strong suppression at low transverse momentum and gradually increases with pT. The data are compared to high-pT STAR results and previously published BNL Relativistic Heavy Ion Collider results. Comparing with model calculations, it is found that the invariant yields …