Studies for a Photon Collider at the ILC

One option at the International Linear Collider is to convert the electron beams into high energy photon beams by Compton scattering a few millimetres in front of the interaction region. Selected physics channels for this option have been analysed and technical issues have been studied. So far no showstoppers for this option have been found.Comment: V2: Minor changes, accepted by NI

Studies on Chargino production and decay at a photon collider

A Monte-Carlo analysis on production and decay of supersymmetric charginos at a future photon-collider is presented. A photon collider offers the possibility of a direct branching-ratio measurement. In this study, the process γγ → ˜χ + 1 ˜χ − 1 → W + W − ˜χ 0 1 ˜χ0 1 → q¯qq¯q˜χ0 1 ˜χ0 1 has been considered for a specific mSUGRA scenario. Various backgrounds and a parameterised detector simulation have been included. Depending on the centre-of-mass energy, a statistical error for the directly measurable branching ratio BR(˜χ ± 1 → ˜χ0 1 W ± ) of up to 3.5% can be reached.