Dark matter of any spin -- an effective field theory and applications

Abstract

We develop an effective field theory of a generic massive particle of any spin and, as an example, apply this to study higher-spin dark matter (DM). Our formalism does not introduce unphysical degrees of freedom, thus avoiding the potential inconsistencies that may appear in other fieldtheoretical descriptions of higher spin. Being a useful reformulation of the Weinberg's original idea, the proposed effective field theory allows for consistent computations of physical observables for general-spin particles, although it does not admit a Lagrangian description. As a specific realization, we explore the phenomenology of a general-spin singlet with Z2-symmetric Higgs portal couplings, a setup which automatically arises for high spin, and show that higher spin particles with masses above O(10) TeV can be viable thermally-produced DM candidates. Most importantly, if the general-spin DM has purely parity-odd couplings, it naturally avoids all DM direct detection bounds, in which case its mass can lie below the electroweak scale. Our formalism reproduces the existing results for low-spin DM, and allows one to develop consistent higher-spin particle physics phenomenology for high-and low-energy experiments and cosmology.

Massive Higher-Spin Multiplets and Asymptotic Freedom in Quantum Gravity

“…Moreover, massive higher-spin fields are also considered in non-conventional representations of the Lorentz group and used to directly derive S-matrix elements without relying on a Lagrangian description [19]. This framework has been recently adopted in the context of dark matter phenomenology [20,21].…”

Confronting spin-3/2 and other new fermions with the muon g-2 measurement

“…In this paper, we confront the new (g − 2) µ result with the predictions coming from models beyond the SM, which contain new fermions. In particular, we consider the case of a massive electrically neutral and colourless spin-3/2 particle which was recently discussed [6,7] but, to our knowledge, not in the context of lepton magnetic moments. We use the new measurement to derive constraints on the properties of these particles and compare these constraints with the existing ones on other spin-1/2 fermions appearing in various supersymmetric and non-supersymmetric theories beyond the SM.…”

“…Massive higher-spin particles, in particular spin-3/2 fermions in addition to spin-2 bosons are present in many supersymmetric extensions of gravity [8][9][10][11], and are also predicted in string-theoretical frameworks [12,13]. Furthermore, they are of interest on purely phenomenological grounds as, for instance, they may constitute dark matter (DM) [6,[14][15][16][17], or appear in the form of non-conventional experimental signatures at the LHC and future colliders [7]. As presently there is no well-motivated paradigm for searching for new phenomena beyond the SM, all possible directions must be pursued in the search for new physics and thus, considering the possibility of higher-spin fields is certainly worthwhile.…”

“…These difficulties are circumvented in the recently developed effective field theory (EFT) approach to generic higher-spin particles [6,7]. This approach considers only the physical degrees of freedom of the higher-spin fields, and thus, although not admitting a Lagrangian description [6,23], allows for a consistent calculation of physical observables.…”

“…These difficulties are circumvented in the recently developed effective field theory (EFT) approach to generic higher-spin particles [6,7]. This approach considers only the physical degrees of freedom of the higher-spin fields, and thus, although not admitting a Lagrangian description [6,23], allows for a consistent calculation of physical observables. It was successfully applied to study the DM [6] and high-energy collider phenomenology [7] of electrically neutral and colour singlet higher-spin particles, with emphasis on spin-3/2 fermions and spin-2 bosons.…”