Prospects of boosted magnetic dipole inelastic fermion dark matter at ILC-BDX

TL;DR

This paper assesses the sensitivity of the ILC-BDX experiment to inelastic fermionic dark matter with magnetic dipole interactions, focusing on production, propagation, and detection of boosted dark matter fluxes.

Contribution

It provides the first detailed sensitivity analysis of ILC-BDX for inelastic magnetic dipole dark matter, considering specific mass splittings and realistic experimental parameters.

Findings

ILC-BDX can probe relevant parameter space of inelastic magnetic dipole dark matter.

Projected exclusion limits are derived for 1 and 10 years of data taking.

The experiment is sensitive to dark matter with specific mass splittings and magnetic dipole couplings.

Abstract

In this work, we investigate the projected sensitivity of the Beam-Dump eXperiment at the International Linear Collider (ILC-BDX) to inelastic fermionic dark matter coupled to the Standard Model photon through an off-diagonal magnetic dipole operator. We compute the production rate of dark matter states in the bremsstrahlung like process $e^- N \to e^- N \gamma^* (\to \chi_{1} \bar{\chi}_0)$, induced by the scattering of high-energy electrons on target nuclei. The resulting boosted dark matter fluxes are then propagated to the detector, where the signal events arise from scattering off detector electrons. The projected exclusion limits are derived using the expected numbers of electrons on target (this implies a typical rate of $4.0~\times~10^{21}/\mbox{year}$) corresponding to 1 year and 10 years of data taking. To characterize the impact of inelasticity, we consider two benchmark relative mass splittings, $\Delta=0.05$ and $\Delta=0.001$, motivated by thermal dark matter scenarios. Our results show that ILC-BDX can probe inelastic magnetic-dipole dark matter over a phenomenologically relevant region of parameter space.