报告题目：Measurements of photon interactions in hadronic heavy-ioncollisions

报告人：Shuai Yang

Brookhaven National Laboratory

邀请人：易立教授

报告时间：2018年10月26日(周五) 10：00

报告地点：青岛校区N7 122报告厅

报告摘要：

Strong electromagnetic fields arising from highly charged, relativistic heavy ions can be treated as quasi-real photons. These photons induce a wide variety of photonuclear and photon-photon physics, which were conventionally and extensively studied in ultraperipheral collisions (UPCs). Recently, a significant excess ofJ/ψyields at low transverse momenta (p_T) was observed by the ALICE Collaboration in peripheral heavy-ion collisions, qualitatively explained by coherent photonuclear production mechanisms. That explanation implies photon-photon interactions would also occur and contribute to the dilepton production. Since the nuclei are broken in peripheral heavy-ion collisions, it is non-trivial to incorporate the coherence conditions for the aforementioned photon interactions in hadronic heavy-ion collisions. Measurements of e⁺e⁻pair production at lowp_Tfor different collision systems and energies, discussed in this talk, thus are important to verify and further constrain photon interactions and their possible impacts on emerging phenomena in hadronic heavy-ion collisions.