Dilepton Measurements at STAR

Abstract

In the study of hot and dense nuclear matter, created in relativistic heavy-ion collisions, dilepton measurements play an essential role. Leptons, when compared to hadrons, have only little interaction with the strongly interacting system. Thus, dileptons provide ideal penetrating probes that allow the study of such a system throughout its space-time evolution. In the low mass range ($M_{ll}<1.1$ GeV/$c^2$), the dominant source of dileptons originates from the decay of vector mesons which may see effects from chiral symmetry restoration. In the intermediate mass range ($1.1<M_{ll}<3.0$ GeV/$c^2$), the main contributions to the mass spectrum are expected to originate from the thermal radiation of a quark-gluon plasma as well as the decays of charm mesons. In the high mass range ($M_{ll}>3.0$ GeV/$c^2$), dilepton measurements are expected to see contributions from primordial processes involving heavy quarks, and Drell-Yan production. With the introduction of the Time-of-Flight detector, the STAR detector has been able to perform large acceptance, high purity electron identification. In this contribution, we will present STAR's recent dielectron measurements in the low and intermediate mass range for RHIC beam energies ranging between 19.6 and 200 GeV. Compared to electrons, muon measurements have the advantage of reduced bremsstrahlung radiation in the surrounding detector materials. With the upcoming detector upgrades, specifically the muon detector (MTD), STAR will be able to include such measurements in its (di-)lepton studies. We will discuss the future dilepton program at STAR and the physics cases for these upgrades.

10 pages, 11 figures. Proceedings of the 29th Winter Workshop on Nuclear Dynamics (WWND 2013), Squaw Valley, CA

References in corpus (6)

• Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions
• Evidence for the production of thermal muon pairs with masses above 1 GeV/c^2 in 158A GeV Indium-Indium Collisions
• Modification of the rho meson detected by low-mass electron-positron pairs in central Pb-Au collisions at 158 A GeV/c
• Evidence for radial flow of thermal dileptons in high-energy nuclear collisions
• Elliptic flow of thermal dileptons in relativistic nuclear collisions
• Di-electron spectrum at mid-rapidity in $p+p$ collisions at $\sqrt{s}=200$ GeV

Cited by in corpus (5)

• Dilepton production and reaction dynamics in heavy-ion collisions at SIS energies from coarse-grained transport simulations
• The contribution of NLO and LPM corrections to thermal dilepton emission in heavy ion collisions
• Holographically emulating sequential versus instantaneous disappearance of vector mesons in a hot environment
• Dimuon production from in-medium rho decays from QCD sum rules
• Hadronic matter at the edge: A survey of some theoretical approaches to the physics of the QCD phase diagram