Gravity-Higgs portal for dark matter decay

Abstract

Dark matter can decay via gravity portals and contribute a minor decay (MD) width. This paper proposes that nonminimal coupling between the Higgs field and gravity can lead to additional gravity-Higgs portals for gravitational dark matter to decay and contribute additional decay (AD) width. For scalar dark matter candidates with a mass less than 5 TeV, the decay branching ratios are almost independent of whether dark matter decay through gravity portals or gravity-Higgs portals; therefore, it is almost impossible to distinguish gravity portals from gravity-Higgs portals by observing decay products. For fermionic singlet dark matter candidates, their MD products are diverse, while their AD products are monotonous, only neutrinos and Higgs bosons. As for both dark matter candidates, gravity-Higgs portals prefer to dominate the decay at around several hundred GeV. Besides, for both TeV dark matter candidates, there is still a vast parameter space alive.

A general study of decaying scalar dark matter: existing limits and projected radio signals at the SKA

“…Moreover, continuous global symmetries may be broken by interactions suppressed by the Planck scale [28,36,37]. Therefore, scenarios where the GeV -TeV scale DM particles are stable in the cosmological time scales but decay afterwards, are not uncommon [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32].…”

“…Several scenarios of TeV-scale decaying scalar DM which decays to SM leptons [24,25,30,89,90] have been proposed in the context of the positron excesses observed in PAMELA [52] and AMS-02 [91]. Apart from these, decays of GeV -TeV scale scalar DM particles via non-minimal couplings to the Ricci scalar (R) [31] or via higgs-gravity portal interactions [32] are also studied in the literature. In the SUSY context, right-handed sneutrinos (ν R ) couple to left-handed sneutrinos (ν L ) via Dirac neutrino Yukawa coupling and decays to SM leptons by means of the trilinear R-parity breaking interaction terms [29].…”

“…This immediately raises another curiosity: can the frequently postulated symmetry disallowing DM decays be broken in such a way that the DM candidate may decay into SM particle pairs at extremely slow rates? The observed large scale structure of our Universe requires the DM particle to be long-lived only on a cosmological time scale, and the possibility that the DM decays with a lifetime much larger than the age of the Universe is thus not JCAP09(2022)005 inconceivable [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. It is a likely proposition that the long-lived nature of the DM candidate is due to some continuous global symmetry [33][34][35].…”

The role of vectors in reheating

“…In addition to the role of vectors in the reheating process, massive vectors may also be produced through scattering, involving either a single graviton exchange or a gravitational portal [57][58][59][60][61][63][64][65][66][67][68]. Related mechanisms for the gravitational production of particles during reheating were also considered in .…”