Dielectron production in Au plus Au collisions at root s(NN)=200 GeV

Thumbnail Image
Date
2016-01-11
Authors
Adare, Andrew
Apadula, Nicole
Campbell, Sarah
Ding, Lei
Dion, Alan
Hill, John
Hotvedt, Nels
Kempel, Todd
Lajoie, John
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Authors
Person
Ogilvie, Craig
Contingent Worker
Research Projects
Organizational Units
Organizational Unit
Physics and Astronomy
Physics and astronomy are basic natural sciences which attempt to describe and provide an understanding of both our world and our universe. Physics serves as the underpinning of many different disciplines including the other natural sciences and technological areas.
Journal Issue
Is Version Of
Versions
Series
Department
Physics and Astronomy
Abstract

We present measurements of e(+)e-production at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (m(ee) < 5 GeV/c(2)) and pair transverse momentum (p(T) < 5 GeV/c) for minimum bias and for five centrality classes. The e(+)e(-) yield is compared to the expectations from known sources. In the low-mass region (m(ee) = 0.30-0.76 GeV/c(2)) there is an enhancement that increases with centrality and is distributed over the entire pair p(T) range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to 2.3 +/- 0.4(stat) +/- 0.4(syst) +/- 0.2(model) or to 1.7 +/- 0.3(stat) +/- 0.3(syst) +/- 0.2(model) for minimum bias collisions when the open heavy-flavor contribution is calculated with PYTHIA or MC@NLO, respectively. The inclusive mass and p(T) distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the rho meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (m(ee) = 1.2-2.8 GeV/c(2)), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.

Comments

This is an article from Physical Review C 93 (2016): 014904, doi:10.1103/PhysRevC.93.014904. Posted with permission.

Description
Keywords
Citation
DOI
Subject Categories
Copyright
Fri Jan 01 00:00:00 UTC 2016
Collections