# Leading Loop Effects in Pseudoscalar-Higgs Portal Dark Matter

## TL;DR

This paper analyzes a pseudoscalar-Higgs portal dark matter model, showing that loop effects significantly impact direct detection prospects and identifying parameter regions testable by future experiments.

## Contribution

It provides an analytical calculation of loop contributions to dark matter scattering, revealing their importance in models with suppressed tree-level interactions.

## Key findings

- Loop effects are sizable in large parameter regions.
- Viable parameter space consistent with current constraints.
- Future experiments like XENONnT can probe these regions.

## Abstract

We examine a model with a fermionic dark matter candidate having pseudoscalar interaction with the standard model particles where its direct detection elastic scattering cross section at tree level is highly suppressed. We then calculate analytically the leading loop contribution to the spin independent scattering cross section. It turns out that these loop effects are sizable over a large region of the parameter space. Taking constraints from direct detection experiments, the invisible Higgs decay measurements, observed DM relic density, we find viable regions which are within reach in the future direct detection experiments such as XENONnT.