Supersymmetric Dark Matter and the Energy of a Linear Electron-Positron Collider

TL;DR

This paper proposes using supersymmetric dark matter constraints to determine the energy scale of a linear electron-positron collider, showing that a 1.5 TeV collider can explore the entire relevant parameter space.

Contribution

It evaluates the collider energy needed to fully explore the supersymmetric dark matter parameter space based on relic density calculations.

Findings

A 500 GeV collider explores part of the dark matter region.

A 1 TeV collider explores more but not all of the region.

A 1.5 TeV collider can explore the entire supersymmetric dark matter parameter space.

Abstract

We suggest that supersymmetric dark matter be used to set the energy scale of a linear $e^+ e^-$ collider. Assuming that the lightest supersymmetric particle (LSP) is a stable neutralino $\chi$, as in many incarnations of the MSSM with conserved R parity, previous calculations that include coannihilation effects have delineated the region of the $(m_{1/2}, m_0)$ plane where the LSP cosmological relic density lies in the preferred range $0.1 \la \Omega_{\chi} h^2 \la 0.3$. We evaluate here the total cross section for $e^+ e^- \to$ visible pairs of supersymmetric particles, for different values of $m_{1/2}$ and $m_0$, and investigate how much of the dark matter region can be explored by $e^+ e^-$ colliders with different centre-of-mass energies $E_{CM}$. We find that a collider with $E_{CM} = 500$ GeV or 1 TeV can only explore part of the cosmological region, and that a collider with $E_{CM} = 1.5$ TeV with sufficient luminosity can explore all of the supersymmetric dark matter region.