Speaker
Deepali Sharma
(S)
Description
Di-electrons are among the most promising probes for studying the
early, hot and dense stages created in relativistic heavy-ion
collisions. They are color neutral and so interact only
electromagnetically, thus carrying to the detectors information about
the conditions and properties of the medium at the time of their
creation. The di-electrons are emitted over the the entire space-time
evolution of the collision and their spectrum thus carries a wealth of
information.
PHENIX has measured a large, unexpected enhancement in $Au+Au$ collisions
in the low mass region ( 0.2 - 0.8 GeV/c$^2$ ), with respect to the baseline
cocktail scaled from $p+p$ collisions. However, this result suffers from
a large systematic uncertainty due to the huge combinatorial
background of uncorrelated pairs from partially reconstructed $\pi^0$
Dalitz decays and $\gamma$ conversions.
To combat this challenge, PHENIX installed a hadron blind detector
( HBD ) for the 2009 and 2010 RHIC runs. Its purpose is to tag and
reject the combinatorial background coming from these decays. A
reliable analysis of the 2010 $Au+Au$ data hinges on a complete
understanding of the HBD and its unique characteristics. The 2009
$p+p$ run serves as a crucial testing ground for understanding the
systematics associated with this novel detector. The
proof-of-principle obtained in the $p+p$ HBD analysis will be
presented in this poster.
Author
Deepali Sharma
(S)
