Effective theories for Dark Matter interactions and the neutrino portal paradigm

Abstract

In this article we discuss a general effective-theory description of a multicomponent dark sector with an unspecified non-trivial symmetry and its interactions with the Standard Model generated by the exchange of heavy mediators. We then categorize the relevant effective operators given the current experimental sensistivity where the underlying theory is weakly coupled and renormalizable, with neutral mediators: either scalars or fermions. An interesting scenario resulting from this categorization is the neutrino portal, where only fermion mediators are present, and where the dark sector consists of fermions and scalars such that the lightest dark particle is a fermion, this scenario is characterized by having naturally suppressed couplings of the DM to all SM particles except the neutrinos and has received little attention in the literature. We find that there is a wide region in parameter space allowed by the current experimental constraints (relic abundance, direct and indirect detection limits); the cleanest signature of this paradigm is the presence of monochromatic neutrino lines with energy equal to that of the DM mass, but experimental sensitivity would have to be improved significantly before this can be probed.

A realistic model for dark matter interactions in the neutrino portal paradigm

“…2); as argued on general grounds in [29], they are loop-generated within the neutrino portal scenario.…”

“…The general considerations in [29], however, do not necessarily demonstrate the full phenomenological viability of this scenario since there might be additional effects of the F that are not associated with the dark sector, and which may set further constraints. In this paper we will construct the simplest specific model that realizes such a scenario and investigate the implications of existing and projected experimental restrictions on the model parameters.…”

“…1 The above paradigm has given rise to a large number of publications proposing specific models of DM-SM interactions [19][20][21][22][23][24], as well as phenomenological descriptions of these interactions based on the effective Lagrangian approach (see, for example, [16,[25][26][27][28]). In particular, reference [29] describes a possible scenario that ensures naturally small direct and indirect detection signals, without compromising the relic abundance inferred from CMB experiments. This scenario is based on the assumption that interactions between the dark and SM sectors are mediated by one or more Dirac fermions F , assumed neutral…”

Quintessential Affleck–Dine baryogenesis with non-minimal couplings

“…The generation of this primordial leptonic asymmetry can take place through a variety of processes that depend on the particular embedding of the AD field on beyond the Standard Model scenarios. A potential transferring mechanism involving the neutrino portal operator [60,61] was identified in Ref. [19].…”

Thermal neutrino portal to sub-MeV dark matter

“…II B. Near-future CMB-S3 and S4 experiments, consisting of a collection of groundbased telescopes, will have unprecedented sensitivity to deviations of ∆N eff 0.06 and 0.027 within 1σ, respectively[77]. As noted in Eq (22),. the presence of even a single sub-MeV degree of freedom in the HS that relativistically equilibrates with the SM neutrinos below an MeV implies that ∆N eff 0.18 at the time of recombination.…”