【摘要】 通过计算给出了在LHC能区非对心核一核碰撞中由椭圆流v₂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v₂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v₂随粒子横动量p_T的变化趋势与RHIC上的实验结果一致,但LHC能区较RHIC能区直接光子流v₂值更小,且v₂值由负到正对应的转换p_T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.更多还原

【Abstract】 The azimuthal anisotropy of high p_T direct photons is investigated by using the coefficient of elliptic flow v₂ in non-central nuclear-nuclear collision at LHC energies. These photons come from the radiation induced by the interaction between jet and hot/ dense medium.We find that there isπ/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 p_T at LHC energy is found to be 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 which the direct photon v₂ changes from negative value to positive at LHC is higher than that at RHIC.We conclude it is because the enhanced jet-quenching effect and enhanced contribution for the elliptic flow v₂ of the direct photons emitted from surface at LHC energy.更多还原