Gale Charles, Hidaka Yoshimasa, Jeon Sangyong, Lin Shu, Paquet Jean-François, Pisarski Robert D, Satow Daisuke, Skokov Vladimir V, Vujanovic Gojko
Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.
Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main, Germany.
Phys Rev Lett. 2015 Feb 20;114(7):072301. doi: 10.1103/PhysRevLett.114.072301.
We consider a nonperturbative approach to the thermal production of dileptons and photons at temperatures near the critical temperature in QCD. The suppression of colored excitations at low temperature is modeled by including a small value of the Polyakov loop, in a "semi"-quark-gluon plasma (QGP). Comparing the semi-QGP to the perturbative QGP, we find a mild enhancement of thermal dileptons. In contrast, to leading logarithmic order in weak coupling there are far fewer hard photons from the semi-QGP than the usual QGP. To illustrate the possible effects on photon and dilepton production in heavy-ion collisions, we integrate the rate with a simulation using ideal hydrodynamics. Dileptons uniformly exhibit a small flow, but the strong suppression of photons in the semi-QGP tends to weight the elliptical flow of photons to that generated in the hadronic phase.
我们考虑一种非微扰方法,用于研究在 QCD 临界温度附近温度下双轻子和光子的热产生。在“半”夸克-胶子等离子体(QGP)中,通过纳入一个小的 Polyakov 圈值来模拟低温下色激发的抑制。将半 QGP 与微扰 QGP 进行比较,我们发现热双轻子有适度增强。相比之下,在弱耦合的主导对数阶下,半 QGP 产生的硬光子比通常的 QGP 少得多。为了说明对重离子碰撞中光子和双轻子产生的可能影响,我们使用理想流体动力学模拟对速率进行积分。双轻子普遍表现出小的流,但半 QGP 中光子的强烈抑制倾向于使光子的椭圆流权重与强子相产生的椭圆流权重相同。