Measurement of polarisation transfer in hyperon photoproduction at MAMI

The photoproduction of K+ mesons is an important challenge to recent QCD based chiral perturbation theories in the strange quark sector and is an important constraint on the nucleon excitation spectrum. We present preliminary data from a new high precision measurement using the Crystal Ball detector. The measurement pioneers a new technique for tagging strangeness using detailed cluster analysis in segmented calorimeters which has potential wider application at present and future hadron physics facilities.