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

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 $0.1\text{la}{\Omega }_{\chi }{h}^2\text{la}0.3$. 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.

Comments: 14 pages, latex, 4 eps figures