A Diagrammatic Analysis of Two-Body Charmed Baryon Decays with Flavor Symmetry
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Springer
Received: November Revised: November Accepted: February Published: February
30, 28, 12, 26,
2018 2019 2020 2020
H.J. Zhao,a Yan-Li Wang,a Y.K. Hsiaoa and Yao Yub a
School of Physics and Information Engineering, Shanxi Normal University, Linfen 041004, China b Chongqing University of Posts & Telecommunications, Chongqing, 400065, China
E-mail: [email protected], [email protected], [email protected], [email protected] Abstract: We study the two-body anti-triplet charmed baryon decays based on the diagrammatic approach with SU(3) flavor symmetry. We extract the two W -exchange ef0 + fects as EB and E 0 that contribute to the Λ+ c → Ξ K decay, together with the relative 0 phases, where EB gives the main contribution. Besides, we find that B(Λ+ c → pπ ) = −4 (0.8+0.9 −0.8 ) × 10 , which is within the experimental upper bound. Particularly, we obtain 0 + −3 0 − + 0 ¯0 −2 B(Ξ+ c → Ξ π ) = (9.3 ± 3.6) × 10 , B(Ξc → Ξ π , Λ K ) = (19.3 ± 2.8, 8.3 ± 5.0) × 10 0 − + −4 and B(Ξc → Ξ K ) = (5.6 ± 0.8) × 10 , which all agree with the data. For the + + 0 + 0 singly Cabibbo suppressed Λ+ c decays, we predict that B(Λc → nπ , pη , Σ K ) = (7.7 ± 2.0, 7.1±1.4, 19.1±4.8)×10−4 , which are accessible to the experiments at BESIII, BELLEII and LHCb. Keywords: Branching fraction, Charm physics, Flavor physics, Rare decay, e+-e- Experiments ArXiv ePrint: 1811.07265
c The Authors. Open Access, Article funded by SCOAP3 .
https://doi.org/10.1007/JHEP02(2020)165
JHEP02(2020)165
A diagrammatic analysis of two-body charmed baryon decays with flavor symmetry
Contents 1
2 Diagrammatic approach
2
3 Numerical results
3
4 Discussions and conclusions
5
1
Introduction
The experimental studies of two-body Bc → BM decays have provided important information for the theoretical understanding of the hadronization in the weak interaction, where + Bc = (Ξ0c , Ξ+ c , Λc ) are the lowest-lying anti-triplet charmed baryon states, and B(M ) the baryon (meson) state. For example, the BESIII collaboration has recently measured the purely non-factorizable decays, of which the branching fractions are given by [1] 0 + −3 B(Λ+ , c → Ξ K ) = (5.90 ± 0.86 ± 0.39) × 10
∗0 + −3 B(Λ+ , c → Ξ K ) = (5.02 ± 0.99 ± 0.31) × 10
(1.1)
with Ξ∗0 ≡ Ξ(1530)0 . This implies that the non-factorizable effects can be as significant as the factorizable ones in Bc → BM [2, 3], although being often neglected in the b-hadron decays [4–7]. Some theoretical approaches have tried to deal with the non-factorizable effects [8–12]. 0 + Nonetheless, B(Λ+ c → Ξ K ) is calculated to be 2–6 times smaller than the observation. Without involving the detailed dynamics, the approach based on the SU(3) flavor (SU(3)f ) symmetry is able to receive all contributions [13–31], such that B(Bc → BM ) 0 + can be explained [22–25]; particularly, B(Λ+ c → Ξ K ). However, the SU(3)f symmetry mixes the factorizable and non-factorizable effects, instead of quantifying their individual contributions. As depicted in figure 1, one can identify the (non-)factoriable effects by the topolog
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