Speaker
Mihael Makek
(PMF)
Description
Dileptons are an important probe of the dense medium created in
heavy-ion collisions, with sensitivity to chiral symmetry
restoration, thermal radiation and in-medium effects. The PHENIX
Hadron-Blind Detector (HBD), which took data during RHIC runs
2009--2010, is a proximity-focusing \v{C}erenkov detector operated
with pure CF4, directly coupled to a triple GEM readout in a
windowless configuration. The HBD was designed to improve the
measurement of low-mass dileptons with the aim of confirming or
refuting the earlier PHENIX measurement of a strong excess of
low-mass di-electrons in central Au$+$Au collisions. A new,
significantly improved analysis procedure has been developed that
enables a quantitative understanding of the background in the
low-mass region at a sub-percent level. We present the final
di-electron results obtained with the PHENIX HBD for Au+Au
collisions at $\sqrt{s_{NN}}$=200 GeV, including invariant mass
spectra, transverse momentum distributions, and centrality
dependence. The results will be compared to published results and to
model calculations.
| On behalf of collaboration: | PHENIX |
|---|
Author
Mihael Makek
(PMF)
