Phenomenological implications on a hidden sector from the festina lente bound
Kayoung Ban (Department of Physics & IPAP & Lab for Dark Universe, Yonsei University, , , Seoul 03722, , , Republic of Korea); Dhong Yeon Cheong (Department of Physics & IPAP & Lab for Dark Universe, Yonsei University, , , Seoul 03722, , , Republic of Korea); Hiroshi Okada (Department of Physics, Pohang University of Science and Technology, , , Pohang 37673, , , Republic of Korea, Asia Pacific Center for Theoretical Physics (APCTP), , , Pohang 37673, , , Republic of Korea); Hajime Otsuka (Department of Physics, Kyushu University, , , 744 Motooka, Nishi-ku, Fukuoka 819-0395, , , Japan); Jong-Chul Park (Department of Physics and Institute of Quantum Systems (IQS), Chungnam National University, , , Daejeon 34134, , , Republic of Korea, Center for Theoretical Physics of the Universe (CTPU), Institute for Basic Science (IBS), , , Daejeon 34126, , , Republic of Korea); et al - Show all 6 authors
Abstract We apply the festina lente (FL) bound on a hidden sector with U(1) gauge symmetries. Since the FL bound puts a lower bound on masses of particles charged under the U(1) gauge symmetries, it is possible to constrain the hidden sector even with a tiny coupling to the Standard Model. In particular, we focus on the phenomenological implications of the FL bound on milli-charged particles, which naturally arise when kinetic mixing between the photon and the hidden photon is allowed. It turns out that the milli-charged particle with the mass M ≲ 5 meV is prohibited by the FL bound in the case of a single hidden U(1), insensitively of the value of small kinetic mixing. This bound is crucial when bosonic dark matter is taken into consideration in this framework: the fuzzy bosonic dark matter models requesting minuscule masses are ruled out by the FL bound if the longevity of dark matter is protected by the hidden gauge symmetry.
