The Phenomenology of Quadratically Coupled Ultra Light Dark Matter

TL;DR

This paper explores models of ultralight scalar dark matter with both linear and quadratic couplings to the Standard Model, analyzing their phenomenology, experimental constraints, and theoretical challenges.

Contribution

It extends previous scalar field solutions to include both linear and quadratic couplings, providing a comprehensive analysis of their interplay and experimental bounds.

Findings

Current bounds on linear and quadratic couplings are summarized.

Extended scalar field solutions incorporating both types of interactions.

Discussion of theoretical challenges for natural models with quadratic couplings.

Abstract

We discuss models of ultralight scalar Dark Matter (DM) with linear and quadratic couplings to the Standard Model (SM). In addition to studying the phenomenology of linear and quadratic interactions separately, we examine their interplay. We review the different experiments that can probe such interactions and present the current and expected future bounds on the parameter space. In particular, we discuss the scalar field solution presented in [A. Hees, O. Minazzoli, E. Savalle, Y. V. Stadnik and P. Wolf, Phys.Rev.D 98 (2018) 6, 064051], and extend it to theories that capture both the linear and the quadratic couplings of the DM field to the SM. Furthermore, we discuss the theoretical aspects and the corresponding challenges for natural models in which the quadratic interactions are of phenomenological importance.