Speaker
Description
Dileptons are able to traverse a strongly interacting medium with minimal interactions and thus are excellent probes of the hot, dense, and strongly interacting medium created in relativistic heavy-ion collisions. For the dileptons with an invariant mass less than ~1.2 GeV/c$^{2}$, the production is predominately from vector-meson decays. Information about any in-medium modifications of the vector meson is retained in its decay products, and may provide a possible link to chiral symmetry restoration. In addition, yields from the $\rho$-meson decays and the hot, dense partonic medium can be used as a measurement of the medium’s lifetime. STAR has systematically studied the dielectron invariant mass spectrum in the aforementioned region for a variety of centralities, system-sizes, and collision energies. This presentation will cover the dielectron continuum measurement as a function of centrality, invariant mass, and transverse momentum for U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV; the dielectron continuum measurement as a function of invariant mass for minimum-bias of Au+Au collisions at $\sqrt{s_{NN}}$ = 19.6, 27, 39, and 62.4 GeV; and the acceptance-corrected dielectron excess measurements of U+U collisions at $\sqrt{s_{NN}}$ = 193 and Au+Au collisions at $\sqrt{s_{NN}}$ = 19.6, 27, 39, 62.4, and 200 GeV collisions. The connection between the measured dielectron excess yield and the lifetime of the hot, dense medium will be discussed.
| Presentation type | Oral |
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