A further analysis of $\Theta^+$ production in $\gamma+D \to \Lambda+n+K^{+}$ reaction

Abstract

We analyse Theta+ production in the gamma+D -> \Lambda+n+K+ reaction and study the dependence of the gamma+D -> \Lambda+n+K+ differential cross section on the nK+ invariant mass and on the momentum of the final neutron p_n. We examine the important role of the interference between the signal and background contributions to the gamma+D -> \Lambda+n+K+ amplitude in the extraction of the Theta+ signal from the gamma+D -> \Lambda+n+K+ cross section. We demonstrate that as a result of the cancellation between the interference and signal contributions, the Theta+ signal almost completely washes out after the integration over p_n. This is consistent with the CLAS conclusion that no statistically significant structures in the analysis of the gamma+D -> \Lambda+n+K+ reaction were observed. Therefore, there is no disagreement between the theory and the experiment and the CLAS result does not refute the existence of the Theta+.