Higgsphobic and fermiophobic Z’ as a single dark matter candidate

Abstract

A spin-1 Z' particle as a single dark matter candidate is investigated by assuming that it does not directly couple to the Higgs boson and standard model fermions and does not mix with the photon and Z boson. The remaining dominant vertices are quartic Z ′ Z ′ ZZ and Z ′ Z ′ W + W − , which can induce effective Z ′ Z ′ qq couplings through standard-model gauge-boson loops. We discuss constraints from the cosmological thermal relic density, and direct and indirect-detection experiments, and find that a dark Z' can only exist above the W boson mass threshold, and the effective quartic coupling of Z ′ Z ′ V V is bounded in the region of 10 −3 ∼ 10 −2 .

Direct detection of exothermic dark matter with light mediator

“…In the recent years, several DM direct detection experiments have reported potential signals for light WIMPs with masses around 1 ∼ 10 GeV, including DAMA [8,9], CoGeNT [10][11][12][13][14], CRESST-II [15] and CDMS-Si [16], while other experiments, such as LUX [17,18], SuperCDMS [19], CDMSlite [20,21], XENON10 [22], XENON100 [23,24], CDEX [25,26] and PandaX [27,28], have only presented null results. In order to reconcile the conflicts among the experiments, several mechanisms have been discussed, among which the isospinviolating interactions [30][31][32][33][34][35][36][37][38][39], exothermic scatterings [40][41][42][43][44][45][46] and the light WIMP-nuclus mediators [47,48] are the three main proposals. In particular, after the releases of the 2013 LUX [17] and 2014 SuperCDMS [19] data, it was found [33,45,…”

Exothermic isospin-violating dark matter after SuperCDMS and CDEX

“…Indeed, we have investigated the possibility that instead of treating the extra vector boson as a messenger that connects the DM world with SM particles, we may treat it merely as a single DM candidate[60]. The result reveals that DM of this type must have a mass larger than the weak W boson mass and therefore is unrelated to the present GeV DM, which is a possibility that supports the present choice of a messenger role for the vector boson in our low-energy-region search for DM.…”