Evidence for the Strangeness S=+1 Pentaquark from LEPS and CLAS Experiments

There are now several experimental collaborations that have seen evidence for a narrow state in the mass spectrum of the (nK+) system. Two of these experiments, from the LEPS collaboration in Japan and the CLAS collaboration in the USA, are described briefly. Both use similar photoproduction reactions with a K+K− pair in the final state. In addition, data from the CLAS collaboration for the γp → KsK+n reaction are presented for the first time, which has no prominant peak in the (nK+) mass spectrum when the Ks angle is limited to forward angles.