中文摘要：

通过计算给出了在LHC能区非对心核-核碰撞中由椭圆流ν2表示的高横动量直接光子的方位角不对称性。该高横动量光子是由喷注与热密介质相互作用而辐射出来的。光子椭圆流与强子椭圆流ν2相差π/2的相位,是直接光子椭圆流中负值的来源。同时,计算表明LHC能区直接光子ν2随粒子横动量pT的变化趋势与RHIC上的实验结果一致,但LHC能区较RHIC能区有更低的直接光子流ν2值,且ν2值由负到正对应的转换pT值更高。这表明在LHC能区喷注淬火效应更为明显,表面发射的直接光子对光子椭圆流的贡献份额增强。

英文摘要：

The azimuthal anisotropy of high PT direct photons is investigated by using the coefficient of elliptic flow v2 in non-central nucleus-nucleus collision at LHC energies. These photons come from radiation induced by the interaction between jet and hot/dense medium. There is π/2 difference between direct photons and hadrons for the azimuthal elliptic flow v2. Such photons are the main source of the negative part of v2 for direct photons. The dependence of the direct photon v2 on the transverse momentum PT at LHC energy is found to he consistent with the experimental results at RHIC energy. Furthermore, we find that the value of the direct photon v2 at LHC energy is smaller than that at RHIC energy. The value of the transverse momentum at which the direct photon v2 changes from negative value to positive at LHC is higher than that at RHIC. It＇s found the enhanced jet-quenching effect and enhanced contribution for the elliptic flow v2 of the direct photons emitted from surface at LHC energy.