We have examined the existence of the N*(1685) resonance, which is recently listed by the Particle Data Group as a one-star nucleon resonance, by using a covariant isobar model for kaon photoproduction and assuming that the resonance has Jp=1/2+, in accordance with our previous finding. After the inclusion of this resonance, the changes in the total χ2 show two clear minima at MN*=1650 and 1696 MeV, which correspond to two different resonance states. The former corresponds to the narrow nucleon resonance found in our previous investigation, whereas the latter corresponds to a new resonance found as we increase the resonance width. From the latter we derive the mass and width relation of the N *(1685) resonance. We observe that the properties of both the N*(1685) and N*(1710)P11 resonances are strongly correlated. Although the best fit of the present work yields MN*=1696 MeV and ΓN*=76 MeV, the apparently small N*(1710)P11 coupling constant to the K+Λ channel found in previous investigations suggests that ΓN*â‰35 MeV, which, according to the mass and width relation, corresponds to MN*â‰1680 MeV.
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 30 Sep 2013|