The THDMa revisited

TL;DR

This paper performs a comprehensive scan of the THDMa model, allowing all parameters to vary, and identifies viable regions of parameter space consistent with current constraints, informing future collider searches.

Contribution

It introduces a generic parameter scan of the THDMa model, considering all free parameters simultaneously, unlike previous fixed-parameter studies.

Findings

Identifies allowed parameter regions after applying all current constraints.

Highlights potential signals for future collider experiments.

Provides a comprehensive map of viable THDMa parameter space.

Abstract

The THDMa is a new physics model that extends the scalar sector of the Standard Model by an additional doublet as well as a pseudoscalar singlet and allows for mixing between all possible scalar states. In the gauge-eigenbasis, the additional pseudoscalar serves as a portal to the dark sector, with a priori any dark matter spins states. The option where dark matter is fermionic is currently one of the standard benchmarks for the experimental collaborations, and several searches at the LHC constrain the corresponding parameter space. However, most current studies constrain regions in parameter space by setting all but 2 of the 12 free parameters to fixed values. In this work, we perform a generic scan on this model, allowing all parameters to float. We apply all current theoretical and experimental constraints, including bounds from current searches, recent results from B-physics, in particular B_s -> X_s gamma, as well as bounds from astroparticle physics. We identify regions in the parameter space which are still allowed after these have been applied and which might be interesting for an investigation at current and future collider machines.