Dark matter (DM) searches through studying DM-nucleon coupling strength

Abstract

Dark matter (DM) interacts with ordinary matter through weakly coupling to nucleons. We analyze the coupling strength for DM-proton and DM-neutron respectively utilizing the available data from the most sensitive experiments, XENON1T and SuperCDMS, for a higher (>10 GeV/c2) and a lower mass (<10 GeV/c2) range of DM particles. Subsequently, we calculate the coupling strength constrained by the DAMA claim and a similar experiment (KIMS) using CsI. The results indicate that XENON1T and SuperCDMS are almost fully sensitive to the DM-nucleon coupling strength predicted by the Fermi weak interaction in the higher mass range. As a result, XENON1T is sensitive to the expected small energy associated with the DM-nucleon weak interaction and hence XENON1T provides a strong constrain on the effective mass of DM from ∼1 MeV/c2 to ∼100 MeV/c2, which excludes the mass range of DM between 10 GeV/c2 to 104 GeV/c2 from being detected. In the lower mass range, four experiments are all not sensitive to the DM-nucleon coupling strength expected from the Fermi weak interaction. The DM-nucleon coupling strength, (Zfp+Nfn)2, determined by the DAMA data can be fully ruled out by the most sensitive experiments. This work launches new direction for the current DM experiments to provide the constrains on DM-nucleon coupling strength, which sheds light on DM-nucleon coupling properties between impinging DM particles and target nucleons with null experimental results. Keywords: Dark matter detection, WIMP, Coupling strength