Title: Revising inelastic dark matter direct detection by including the cosmic ray acceleration

Speaker: Chih-Ting Lu (卢致廷), Nanjing Normal University

Time: 2:30pm, May 18 (Thursday) 2023

Location: 理科楼A221

Abstract: The null signal from collider and dark matter (DM) direct detector experiments makes the interaction between DM and visible matter too small to reproduce the correct relic density for many thermal DM models. The remaining parameter space indicates that two almost degenerated states in the dark sector, the inelastic DM scenario, can co-annihilate in the early universe to produce the correct relic density. Regarding the direct detection of the inelastic DM scenario, the virialized DM component from the nearby halo is nonrelativistic and not able to excite the DM ground state, even if the relevant couplings can be considerable. Thus, a DM with a large mass splitting can evade traditional virialized DM direct detection. In this talk, we connect the concept of cosmic-ray accelerated DM in our Milky Way and the direct detection of inelastic scattering in underground detectors to explore spectra that result from several interaction types of the inelastic DM. We find that the mass splitting less than about 1 GeV can still be reachable for cosmic ray accelerated DM with mass range from 1 MeV to 100 GeV and sub-GeV light mediator.

Bio: Chih-Ting Lu, associate professor of Nanjing Normal University; He received his Ph.D. degree from Tsing Hua University (Hsinchu, Taiwan) in 2015, and then engaged in post-doctoral research at the Center for Theoretical Sciences in Taiwan and Korea Institute for Advanced Study in Korea. His main research topics include collider physics phenomenology, Higgs physics, dark matter physics, and etc. Recently, he focuses on light dark matter issues, including the search for light dark matter in accelerator and direct detection experiments as well as model building.