Title: Atomic dark matter: direct detection, self-interaction and the 3.5 keV X-ray excess 

Speaker: 刘左伟 教授 （清华大学） 

Time: 10:00AM, Aug. 25th (Monday) 

Place: Theoretical Physics Division，319 

Abstract：I will introduce a class of dark matter models in which the dark matter particle is a bound state of two fundamental fermions (in the hidden sector). The binding force of the dark matter atom is the new gauge boson in the hidden sector. I will discuss various experimental constraints (including collider and cosmology) on such dark matter models. A kinetic mixing term between the hidden sector gauge boson and the photon is added to directly detect the atomic dark matter. I will discuss the connection between the self interaction cross section of the atomic dark matter and the galaxy structure problems, such as cuspy problem. The atomic dark matter is also capable of explaining the recent 3.5 keV X-ray excess via hyperfine transitions.