Cancellation in Dark Matter-Nucleon Interactions: the Role of Non-Standard-Model-like Yukawa Couplings

TL;DR

This paper explores how non-Standard-Model-like light-quark Yukawa couplings can cause cancellations in dark matter-nucleon interactions, potentially explaining null results in direct detection experiments and offering new avenues for probing dark matter at the LHC.

Contribution

It introduces the role of non-SM Yukawa couplings in dark matter interactions, highlighting their impact on scattering cancellations and experimental detectability.

Findings

Cancellation effects can suppress direct detection signals.

Non-SM Yukawa couplings may cause isospin violation.

High-luminosity LHC can probe these non-standard couplings.

Abstract

Extensive searches to probe the particle nature of dark matter (DM) have been going on for some decades now but, so far, no conclusive evidence has been found. Among various options, the Weakly Interacting Massive Particles (WIMP) remains one of the prime possibilities as candidates for DM near the TeV scale. Taking a phenomenological view, such null results may be explained for a generic WIMP in a Higgs-portal scenario if we allow the light-quark Yukawa couplings to assume non-Standard Model (non-SM)-like values. This follows from a cancellation among different terms in the DM-nucleon scattering which can, in turn, lead to a vanishingly small direct-detection cross section. It might also lead to isospin violation in the DM-nucleon scattering. Such non-SM values of light-quark Yukawa couplings may be probed in the high luminosity run of the LHC.