Strongly-interacting massive particle and dark photon in the era of the intensity frontier
Ayuki Kamada (Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS), 55 Expo-ro, Yuseong-gu, Daejeon 34126, Korea); Masaki Yamada (Department of Physics, Tohoku University, Sendai, Miyagi 980-8578, Japan, Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan); Tsutomu T. Yanagida (Kavli IPMU (WPI), UTIAS, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan, T. D. Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Rd, Shanghai 200240, China)
A strongly interacting massive particle (SIMP) is an interesting candidate for dark matter (DM) because its self-interaction cross section can be naturally strong enough to address the astrophysical problem of small-scale structure formation. A simple model was proposed by assuming a monopole condensation, where composite SIMP comes from a “strongly interacting” gauge theory. In the original model, the DM relic abundance is determined by the annihilation process via the Wess-Zumino-Witten term. In this paper, we discuss that the DM relic abundance is naturally determined also by a semiannihilation process via a kinetic mixing between the hypercharge gauge boson and the dark gauge boson (dark photon). The dark photon can be discovered by LDMX-style missing momentum experiments in the near future.
