Muonphilic asymmetric dark matter at a future muon collider

TL;DR

This paper assesses how future muon colliders could detect muonphilic portals to fermionic asymmetric dark matter, considering current constraints and potential sensitivities across various models and mass ranges.

Contribution

It provides a comprehensive analysis of the parameter space for muonphilic ADM models, including future collider sensitivities and existing experimental constraints.

Findings

Certain parameter regions are currently allowed by direct detection and collider data.

Future 3 and 10 TeV muon colliders could significantly probe the parameter space.

Constraints from muon g-2 and neutron star heating are incorporated in the analysis.

Abstract

We explore phenomenological constraints on, and future muon collider sensitivities to, the parameter spaces of various muonphilic portals to fermionic asymmetric dark matter (ADM). Both WEFT-level dimension-6 effective operators and two UV models based on gauged $L_\mu - L_\tau$ are considered. One of the latter features a vector coupling to the dark matter and the other an axial vector coupling. The ADM criterion that at least $99\%$ of the dark matter relic density is asymmetric is also imposed. We identify which of these scenarios are currently allowed by direct detection and collider constraints, and then determine how much more of the parameter space could be probed by 3 and 10 TeV muon colliders with 1 ab$^{-1}$ of data. For the UV models, the constraints from $g-2$ of the muon are included. The future sensitivity curves due to neutron star heating considerations are also depicted. We present results for both the few-GeV dark matter mass regime motivated by ADM approaches to the $\Omega_b \simeq \Omega_\text{DM}/5$ coincidence problem, and for larger masses in the context of more general ADM.