Speaker
Jason Kamin
(State University of New York at Stony Brook)
Description
Electron-positron pairs are effective probes for investigating the
hot, dense matter created in RHIC collisions because they are carry no
color charge and therefore, once created, do not interact strongly
with the medium. As a result, they retain characteristics of the full
time evolution and dynamics of the system. Among the many features,
the low mass region (m<1 GeV/c2) consists primarily of pairs from
Dalitz decays of light hadrons and direct decays of vector mesons that
can be modified by the medium, while the intermediate (1<m<3
GeV/c2) and high (4<m<8 GeV/c2) mass regions are dominated
by pairs from mesons containing charm and bottom respectively.
The PHENIX experiment has presented dielectron continuum spectra for
p+p, Cu+Cu and Au+Au collisions at √sNN=200GeV. An
enhancement is observed in Au+Au in the mass range 150<m<750
MeV/c2 when compared to the expected hadronic sources scaled from
p+p collisions. In addition, PHENIX has seen an enhancement in
Cu+Cu collisions in the intermediate mass region, particularly in the
most peripheral collisions, making the d+Au reference extremely
interesting.
Recently PHENIX measured this crucial d+Au reference for heavy ion
collisions. This system not only provides the benefit of identifying
potential initial state effects contributing to the excesses seen in
Au+Au and Cu+Cu but also is a complimentary measurement to the recent
single electron RdA for open charm. The luminosity collected during
the 2008 RHIC Run also allows the d+Au measurement to reach out to
mass ranges where bottom and Drell-Yan dominate. The analysis of this
data is in its final stage and the first results will be presented.
Primary author
Jason Kamin
(State University of New York at Stony Brook)
