On-shell effective theory for higher-spin dark matter

Abstract

We apply the on-shell amplitude techniques in the domain of dark matter. Without evoking fields and Lagrangians, an effective theory for a massive spin-S particle is defined in terms of on-shell amplitudes, which are written down using the massive spinor formalism. This procedure greatly simplifies the study of theories with a higher-spin dark matter particle. In particular, it provides an efficient way to calculate the rates of processes controlling dark matter production, and offers better physical insight into how different processes depend on the relevant scales in the theory. We demonstrate the applicability of these methods by exploring two scenarios where higher-spin DM is produced via the freeze-in mechanism. One scenario is minimal, involving only universal gravitational interactions, and is compatible with dark matter masses in a very broad range from sub-TeV to the GUT scale. The other scenario involves direct coupling of higher-spin DM to the Standard Model via the Higgs intermediary, and leads to a rich phenomenology, including dark matter decay signatures.

A complete effective field theory for dark matter

“…Finally, the restriction to spin up to unity is also made for simplicity; DM with higher spins has been recently considered in refs. [20,21].…”

“…It is typically assumed that the new state is either a scalar, a vector or a fermion, although higher spins have JHEP07(2021)081 been also considered, see refs. [20,21] for recent accounts. Among the simplest and most economical of these EFTs are the Higgs-portal models, in which a single DM particle is introduced in addition to the SM particles; it interacts in pairs only with the Higgs sector of the theory, which is assumed to be minimal [22] and, hence, involves only the unique Higgs boson observed at the LHC [23,24]; see refs.…”

Higher-spin particles at high-energy colliders

“…2 Generic higher-spin DM states have also been studied recently in ref. [44] using on-shell amplitude methods for massive particles [45]. The approach taken in this paper is different from the latter as relies on Feynman rules allowing to construct scattering amplitudes at an arbitrary level in perturbation theory.…”

Gauging the Higher-Spin-Like Symmetries by the Moyal Product. II

“…5 is symmetric we write the previous expression as ((∂•) 2 A) µ (3) . The trace is denoted by square brackets in the superscript δ 2 µµ A µ (5) = δ µ 1 µ 2 δ µ 3 µ 4 A µ 1 µ 2 µ 3 µ 4 µ 5 = A [2]µ . We give two more examples:…”

“…Higher Spin (HS) particles are a natural prediction of string theory, and therefore they can be expected to play quite a crucial role whenever we attempt to include the Standard Model in a consistent theory of Quantum Gravity. In recent years, stopping a historical neglect mainly due to the difficulty of describing them by a straightforward generalization of lower spin cases and their observational elusiveness, they started playing an increasingly relevant role in phenomenological studies of both collider physics and cosmology (see e.g., [1][2][3][4] and references therein). On the theoretical side, the onset of HS degrees of freedom has been put in a close connection to the avoidance of causality problems in graviton scattering amplitudes [5,6] and to the good UV behavior of string theory.…”