ar X iv : h ep - p h / 01 04 10 6 v 1 1 1 A pr 2 00 1 The reach of a future Linear Collider after the g - 2 result F . RICHARD


Combining the cosmological requirement on dark matter with the recent BNL g-2 measurement it is argued that, within the mSUGRA framework, the preferred region for SUSY mass parameters falls well inside the area covered by the future linear colliders under consideration for right handed sleptons and of the 2 lightest neutralinos. The coverage for the lightest chargino and left handed sleptons is also favoured but with smaller confidence. The main uncertainty on the physics potential of future ee colliders comes from our ignorance of the SUSY mass spectrum. As recently pointed out in [1], if the mass spectrum of gauginos (charginos, neutralinos) and sleptons is light enough to be observable with a 500 GeV LC, then signals should appear before LHC starts(2006)either in the precise measurement of g-2 under way at BNL, or in the observation of primordial neutralinos in the high sensitivity experiments under construction (CDMS, EDELWEISS, CRESST). The recent indication [2] reported from the BNL experiment although not yet conclusive (2.6 s.d. effect), is encouraging since it is compatible with the expected contributions of a light SUSY spectrum as will be discussed in more detail below. As already mentioned, there is no definite SUSY symmetry breaking, SSB, mechanism which can allow a precise prediction of the SUSY mass spectrum. In the most general approach this spectrum has more than 100 free parameters but there are various experimental constraints (in particular the requirement to avoid FCNC) which impose to reduce considerably this number. In the so-called gravity-mediated SSB, mSUGRA, there are 2 mass parameters, m0 and m1/2, one related to the mass of the scalar superpartners and the other related to the mass of the fermionic superpartners, and 3 mixing parameters tanβ, μ and A. These parameters enter in the definition of the SUSY particles, the Higgs bosons and the Z masses. The latter provides one constraint which allows to determine μ, leaving unknown sign(μ).

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@inproceedings{Richard2001arXI, title={ar X iv : h ep - p h / 01 04 10 6 v 1 1 1 A pr 2 00 1 The reach of a future Linear Collider after the g - 2 result F . RICHARD}, author={Fr{\'e}d{\'e}ric Richard}, year={2001} }