Akademik Veri Yönetim Sistemi
17th International Conference on Hadron Spectroscopy and Structure, Hadron 2017, Salamanca, İspanya, 25 - 29 Eylül 2017, cilt.310
In this work, we have studied the Λb → J/ψK−p decay via Λ∗-charmonium-proton intermediate states and discussed all possible triangle singularities. Using this process we have done a detailed analysis of the singularities of the triangle amplitude and derived a formula for an easy evaluation of the singularities. We have stressed that the χc1 and the ψ(2S) are the relatively most relevant states among all possible charmonia up to the ψ(2S). Particularly the Λ(1890)χc1 pair plays a very special role, since the threshold and triangle singularities merge. In the case o of JP =3 2 −, 2 5 + for the narrow Pc, one needs P- and D-waves, respectively, in the χc1 p. This feature reduces the strength of the contribution and smoothens very much the peak. In this case the singularities cannot account for the observed narrow peak. On the other hand, for the case of JP =1 2 + or3 2 + with the latter one of the favored quantum numbers, where χc1 p → J/ψ p can proceed in an S-wave, the Λ(1890)χc1 p triangle diagram could play an important role.