Structure of virtual photon polarization in ultrarelativistic heavy-ion collisions

Abstract

Anisotropy in heavy-ion collisions leads to polarization of both direct and virtual photons, the latter detected via internal conversion to dileptons pairs. Thus measurement of photon polarization probes the anisotropy at all stages of collisions. In order to characterize the polarization of virtual photons, we derive here the general structure of the photon polarization operator, rho^(mu nu), in an anisotropic medium, in terms of the four spectral functions, two transverse and one longitudinal, as usual, plus a new spectral function that reflects anisotropy in asymmetric collisions; and derive the local production rate of dilepton pairs in terms of these four functions.

4 pages, 4 figures; proceedings contribution for Quark Matter 2017

References in corpus (5)

• Photon production from an anisotropic quark-gluon plasma
• Measuring Quark-Gluon-Plasma Thermalization Time with Dileptons
• The Cosmic Microwave Background for Pedestrians: A Review for Particle and Nuclear Physicists
• Virtual photon polarization in ultrarelativistic heavy-ion collisions
• Monitoring parton equilibration in heavy ion collisions via dilepton polarization

Cited by in corpus (3)

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• Darker and brighter branes: Suppression and enhancement of photon production in a strongly coupled magnetized plasma
• Emission of linearly polarized photons in a strongly coupled magnetized plasma from the gauge/gravity correspondence