Heavy-flavor-conserving hadronic weak decays of heavy baryons

Abstract

More than two decades ago, we studied heavy-flavor-conserving weak decays of heavy baryons within the framework that incorporates both heavy-quark and chiral symmetries. In view of the first observation of Ξ

Phenomenological study of heavy hadron lifetimes

“…(iii) As pointed out in [61], b-flavor-conserving decays such as Ξ − b → Λ 0 b π − , Λ 0 b e −ν e and Ξ 0 b → Λ 0 b π 0 could affect the total rates of the Ξ b . These heavy-flavor-conserving weak decays were studied more than two decades ago within the framework that incorporates both heavy-quark and chiral symmetries [67,68]. The branching fraction of Ξ b → Λ b π is found to be of order (0.1 ∼ 1)%, consistent with the recent LHCb measurement which lies in the range from (0.57±0.21)% to (0.19±0.07)% [69].…”

Fragmentation-fraction ratio $$f_{\Xi _b}/f_{\Lambda _b}$$ f Ξ b / f Λ

“…[9], f b / f b is assumed to be bounded between 0.1 and 0.3, and then obtain the branching fraction of − b → 0 b π − lie in the range from (0.57 ± 0.21)% to (0.19 ± 0.07)%. On the contrary, the fragmentation ratio [11], the branching fraction of − b → 0 b π − is calculated in the MIT bag model and the diquark model,…”

“…Among them, the absolute branching fraction of + c → pK − π + has never been measured [1], thus is of the largest ambiguity. In this work, we deter- [9] (LHCb) 0.29 ± 0.10 (MIT bag model) [11] 0.08 ± 0.03 (diquark model) [11]…”

S-wave nonleptonic hyperon decays andΞb−→π−Λb

“…However, it has long been noted that strange b-flavored baryons are heavy enough that their s quarks can decay instead via the subprocess s → π − u or su → ud, with the b quark acting as a spectator [1][2][3][4][5][6]. Such processes enable the decays Ξ [7].…”

“…Earlier studies of Ξ − b → π − Λ b (and other heavy-flavor-conserving heavy baryon decays) [1][2][3][4][5][6] have applied current algebra and a soft pion limit, thereby relating this amplitude to a matrix element of a strangeness-changing four-fermion operator between the initial and final heavy baryon states. Calculations of this matrix element are model-dependent and involve large theoretical uncertainties.…”