Title: Thermal photon anisotropic flow serves as a quark-gluon plasma viscometer Show Chinese title

Title: 热光子各向异性流作为夸克-胶子等离子体粘度计

Abstract: Photons are a penetrating probe of the hot and dense medium created in heavy-ion collisions. We present state-of-the-art calculations of viscous photon emission from nuclear collisions at RHIC and LHC. Thermal photons anisotropic flow coefficients v_n are computed, both with and without accounting for viscous corrections to the standard thermal emission rates. These corrections are found to have a larger effect on the v_n coefficients than the viscous suppression of hydrodynamic flow anisotropies. For thermal photons, the ratio v_2{SP}/v_3{SP} shows stronger sensitivity to the quark-gluon plasma (QGP) shear viscosity than for hadrons, and it can thus serve as a sensitive QGP viscometer. Show Chinese abstract

Abstract: 光子是研究重离子碰撞中产生的高温高密度介质的穿透性探针。 我们展示了在RHIC和LHC处核碰撞中粘性光子发射的最新计算。 计算了热光子各向异性流系数v_n，既考虑了标准热发射率的粘性修正，也未考虑这些修正。 发现这些修正对v_n系数的影响大于粘性对流各向异性抑制的影响。 对于热光子，比值v_2{SP}/v_3{SP}对夸克-胶子等离子体（QGP）的剪切粘度比强子更敏感，因此可以作为敏感的QGP粘度计。