Shedding Light on the Dark Sector with Direct WIMP Production

TL;DR

This paper explores the potential of the International Linear Collider to detect and differentiate dark matter candidates called WIMPs through direct production and photon analysis, combining model-independent and model-dependent approaches.

Contribution

It introduces a parametrization of the differential cross section for WIMP production that separates cosmological and particle physics information, and evaluates the ILC's discovery and discrimination capabilities.

Findings

ILC can potentially discover WIMPs in certain parameter regions.

Photon energy spectrum analysis can distinguish between supersymmetric and UED models.

Beam polarization enhances the ability to rule out alternative models.

Abstract

A Weakly Interacting Massive Particle (WIMP) provides an attractive dark matter candidate, and should be within reach of the next generation of high-energy colliders. We consider the process of direct WIMP pair-production, accompanied by an initial-state radiation photon, in electron-positron collisions at the proposed International Linear Collider (ILC). We present a parametrization of the differential cross section for this process which conveniently separates the model-independent information provided by cosmology from the model-dependent inputs from particle physics. As an application, we consider two simple models, one supersymmetric, and another of the "universal extra dimensions" (UED) type. The discovery reach of the ILC and the expected precision of parameter measurements are studied in each model. In addition, for each of the two examples, we also investigate the ability of the ILC to distinguish between the two models through a shape-discrimination analysis of the photon energy spectrum. We show that with sufficient beam polarization the alternative model interpretation can be ruled out in a large part of the relevant parameter space.