报告题目：Dark matter and dark radiation from chiral U(1) gauge symmetry
报告人：Dr. Norimi Yokozaki (浙江大学)
报告时间：10月29日14:00
报告地点：理八栋学术报告厅118
摘要：
We consider a minimal model of a dark sector with a chiral U(1) gauge symmetry. The anomaly-free condition requires at least five chiral fermions. Some of the fermions acquire masses through a vacuum expectation value of a Higgs field, and they are stable due to an accidental symmetry. This makes them dark matter candidates. If the dark sector was once in thermal equilibrium with the Standard Model and dark radiation constraints are included, two-component dark matter may be needed since the number of massless fermions is restricted. When the Dirac fermion is the main component of dark matter, the kinetic mixing should be around 10-6: a larger value is restricted by direct detection limits, while a smaller value prevents thermal freeze-out. If the main dark matter component is a Majorana fermion, the kinetic mixing can be larger. Still, a sub-component of Dirac fermion could produce a detectable signal in future direct detection experiments. We also discuss the possibility of testing an invisible dark photon at future lepton collider experiments, taking into account
报告人简介：
Graduate education in physics was completed at Hiroshima University, Japan, where both master’s and doctoral degrees were conferred between 2006 and 2010. Following graduation, a JSPS Postdoctoral Research Fellowship was held at the Department of Physics, University of Tokyo and Kavli IPMU (University of Tokyo) from 2010 to 2014, with research focus on cosmology and particle physics. The subsequent period, from 2014 to 2016, was spent as a postdoctoral research fellow at INFN, Università di Roma La Sapienza. From 2016 to 2020, an appointment as Assistant Professor in the Department of Physics at Tohoku University involved research activities in cosmology and particle physics. Since 2020, the position of ZJU100 Young Professor at Zhejiang University has centered on theoretical physics research and academic development.