SEMINAR: Direct detection probe of light dark matter and heavier ALP from Sun
by
226
多学科楼
Title: Direct detection probe of light dark matter and heavier ALP from Sun
Abstract:
Current multiton direct-detection experiments place stringent constraints on GeV-scale Galactic dark matter (DM), approaching the neutrino fog, but remain largely insensitive to light DM. Cosmic rays can upscatter nonrelativistic halo DM, producing a relativistic subpopulation with sufficient kinetic energy to become detectable in existing experiments. I will talk about this approach to detect sub-MeV electrophilic DM using the latest LZ 2025 (WS2024) data. We include attenuation of the boosted DM flux during propagation through the Earth and perform a full numerical calculation of the resulting event rate. We find that, for an energy-independent cross section, LZ 2025 improves the constraints on MeV-scale DM by roughly O(1) compared with the previous XENONnT limit. Despite its smaller target mass compared with neutrino detectors, LZ can also provide competitive constraints in certain mediator parameter regions, particularly for light mediators, excluding previously unexplored parameter space.
I will then discuss the production and detection of MeV electrophilic axion-like particles (ALPs) from the Sun. Monochromatic 5.5 MeV photons produced in solar nuclear reactions can undergo Compton-like scattering with ambient electrons, generating a substantial flux of MeV ALPs. Upon reaching Earth, these ALPs can be detected through the same electron coupling, providing a new opportunity for direct-detection experiments to probe previously unexplored parameter space. We use existing data from LZ, PandaX-4T, and Borexino to constrain this scenario.
Speaker information:
Sk Jeesun is a postdoctoral researcher at the Tsung-Dao Lee Institute, Shanghai Jiao Tong University. He obtained his PhD from the Indian Association for the Cultivation of Science, Kolkata, in Aug, 2025. His research focuses on dark matter phenomenology, astroparticle physics, and cosmology, with particular emphasis on light dark matter, beyond Standard-Model particles, and their experimental/cosmological signatures. His work explores connections between particle physics, astrophysical environments, and detection strategies. Recently, he has developed interest in reheating dynamics and its CMB probes.
Spearker webpage: https://tdli.sjtu.edu.cn/en/people/44927/sk-jeesun
Yu Gao, Xiaojun Bi
