# HEP/Astro Seminar -- Wednesday, 08 November 2000

##
Determination of the gaugino mass parameter *M*_{1}
in different linear collider modes

### Abstract

After the LHC the planned Linear Collider (LC) will be the next step
in the search for physics beyond the Standard Model.
The Minimal Supersymmetric Standard Model (MSSM) is one of the favoured
candidates of this search. It is one of the aims of a LC to determine
the underlying parameters of the MSSM with high precision.
One of the free parameters of the MSSM is the U(1) gaugino mass parameter
*M*_{1}. Mostly the SU(2) gaugino mass parameter
*M*_{2} is assumed to be connected with *M*_{1}
via the GUT relation
*M*_{1} = 5/3 tan^{2}θ_{W}
*M*_{2}, which depends on the unification of the gaugino masses
*M*_{1}, *M*_{2} and *M*_{3}
at the GUT-scale. Other supersymmetric models, however, prefer other relations
between *M*_{1}, *M*_{2} and *M*_{3}
at the GUT scale and at the weak scale. Therefore it is necessary to determine
*M*_{1} at a LC to test the GUT relation between
*M*_{1} and *M*_{2}.

For the LC four modes are in discussion:
*e*^{-}*e*^{+},
*e*^{-}*e*^{-}, *e*γ and γγ.
For each mode I will present a special process and discuss its use to determine
*M*_{1}. The talk will end with a comparison of the four modes
of the LC.

## 3:30pm, Smith Lab 1094

George T. Fleming
(
gfleming@mps.ohio-state.edu
),
last updated 08 November 2000.