The new interaction suggested by the anomalous 8 Be transition sets a rigorous constraint on the mass range of dark matter

Abstract

The WIMPs are considered to belong to the favorable dark matter (DM) candidates, but the upper bounds on the interactions between DM and standard model (SM) particles obtained by the upgraded facilities of DM direct detection get lower and lower. Researchers turn their attention to the search for less massive DM candidates, i.e. light dark matter of the MeV scale. The recently measured anomalous transition in 8Be suggests that there exists a vectorial boson which may mediate the interaction between DM and SM particles. Based on this scenario, we combine the relevant cosmological data to constrain the mass range of DM, and we have found that there exists a model parameter space where the requirements are satisfied, a range of 10.4 ≲ mϕ≲ 16.7 MeV for scalar DM, and 13.6 ≲ mV≲ 16.7 MeV for vectorial DM is demanded. Then a possibility of directly detecting such light DM particles via DM–electron scattering is briefly studied in this framework.