mSUGRA At A 500-GeV Linear Collider

Abstract

A study is made of what SUSY signals would be observable for mSUGRA models in a 500-GeV linear collider. All current experimental bounds on the mSUGRA parameter space are imposed. For m_0 < 1 TeV (or alternately if the current g_μ- 2 anomaly maintains) the only observable signals that remain are slepton pair production and neutralino production of {\tildeχ^0_2}+{\tildeχ^0_1}. Slepton pair production can occur for masses < 250 GeV which for the selectron and smuon pairs require tanbeta < 40. In this domain very accurate selectron and smuon masses could be measured. Light staus, \tildeτ_1, with mass < 250 GeV can be pair produced for any tanbeta and the neutralino signal can be seen provided m_{1/2}<~400 GeV. However, the detection of these requires a much more complicated analysis due to the fact that the dark matter co-annihilation constraint requires that the \tildeτ_1 and {\tildeχ^0_1} mass difference be <~ 15 GeV. The point m_{1/2} = 360 GeV, A_0 = 0, μ>0 is analyzed in detail, and it is shown that the stau and neutralino signals can be detected provided an active mask down to 2^o is used. However, large parts of the mSUGRA parameter space exists where a 500-GeV machine would not be able to see any SUSY signal.