Status of the Θ+ analysis at LEPS Original Research Article

We report recent results on the Theta+ study from LEPS. The γd→K+K−pn reaction has been studied to search for the evidence of the Θ+ by detecting K+K− pairs at forward angles. The Fermi-motion corrected nK+ invariant mass distribution shows a narrow peak at 1.53 GeV/c2. The statistical significance of the peak calculated from a shape analysis is 5 σ, and the differential cross-section for the γn→K−Θ+ reaction is estimated to be 12 ± 2 nb/sr in the LEPS angular range by assuming the isotropic production.