Estimates of W -exchange contributions to Ξcc decays

Abstract

Encouraged by the recent discovery of the Ξ cc baryon, we investigate two-body nonleptonic weak decays of doubly charmed, Ξ cc , baryons. We calculate the branching ratios for Cabibbo-Kobayashi-Maskawafavored and -suppressed modes in factorization and pole model approaches. The preliminary estimates of nonfactorizable W-exchange contributions are obtained using the pole model. We find that the W-exchange contributions to Ξ cc decays, being sizable, cannot be ignored.

Two-body weak decays of doubly charmed baryons

“…It is very interesting to notice that our calculation agrees with [11] even though the estimation of nonfactorizable effects is based on entirely different approaches: current algebra and the pole model in this work and the covariant confined quark model in [11]. On the contrary, a large constructive interference in the P -wave amplitude was found in [8], 5 while nonfactorizable corrections to the S-wave one were not considered. This leads to a branching fraction of order (7−9)% ((13−16)%) for flavor-independent (flavor-dependent) pole amplitudes.…”

“…If we turn off the nonfactorizable terms, we will have a branching fraction of order 3.6%. In the literature, nonfactorizable effects in Ξ ++ cc → Ξ + c π + have been considered in [11] and partially in [8] (c.f. Table V).…”

“…we would like to investigate in this work the nonleptonic two-body decays of doubly charmed baryons Ξ ++ cc , Ξ + cc and Ω + cc . This has been studied intensively in the literature [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Many authors [7,12,14,18] considered only the factorizable contributions from the external W -emission governed by the Wilson coefficient a 1 .…”

“…In the same vein, some of these techniques have been applied to the study of W -exchange in doubly charmed baryon decays. For example, W -exchange contributions to the P -wave amplitude were estimated by Dhir and Sharma [8,10] using the pole model. However, nonfactorizable corrections to the Swave amplitudes were not addressed by them.…”

“…This is the case in particular for S-wave terms as they require the information of the troublesome negative-parity baryon resonances which are not well understood in the quark model. This is the main reason why the nonfactorizable S-wave amplitudes of doubly charmed baryon decays were not considered in [8,10] within the pole model.…”