Weak Decays of the Λb Baryon in Light-Front Dynamics
Abstract
We investigate the exclusive semileptonic and nonleptonic Λb → Λc(p) decays within the Standard Model by using the light-front quark model. To determine the behavior of the Λb → Λc(p) transition form factors, we employ the Bethe-Salpeter formalism in the timelike region, effectively accounting for both valence and nonvalence contributions. Using these form factors, including nonvalence contributions, we obtain branching fractions of Λb → Λc ℓ ν̅ℓ, Λb → Λc τ ν̅τ, Λb → p ℓ ν̅ℓ and Λb → p τ ν̅τ~(ℓ=e or μ) are found to be around 5.39%, 1.41%, 3.33× 10−4 and 2.08× 10−4, respectively, which are consistent with the experimental measurements. The ratios of Rℓτ(Λc)=(cal B(Λb→ Λc τ ν̅τ))/(cal B(Λb→ Λc ℓ ν̅l)) and Rℓτ(p)=(cal B(Λb→ p τ ν̅τ))/(cal B(Λb→ p ℓ ν̅l)), are given by 0.261+0.097−0.117 and 0.624+0.119−0.129, respectively. The forward-backward asymmetries in the above semilepton decays are also examined. Our results indicate that, within the light-front framework, the nonvalence contributions to the asymmetries are negligible compared to the β-induced uncertainties. In addition, we calculate the branching ratios for the nonleptonic decays of Λb→ Λc(p) M with M being the pseudo scalar and vector mesons with the results found to be consistent with the current experimental data.
Related
- Semileptonic Decays of Λ→ p ℓ− ν̅ℓ in the Light-Front Dynamics
- Semileptonic B̅*c → (P, V) ℓ- ν̅ℓ decays within the self-consistent light-front quark model
- Baryon-Number Violating Λc Decays from Light-Cone Sum Rules
- Interpolating conformal algebra in (3+1) dimensions between the instant form and the light-front form of relativistic dynamics
- U-spin sum rules in charmed baryon decays beyond the U-spin limit
BibTeX
@misc{lih2026weak,
title = {{Weak Decays of the $Λ_b$ Baryon in Light-Front Dynamics}},
author = {Chong-Chung Lih and Cong-Yu Li and Chao-Qiang Geng},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.16770},
eprint = {2609.16770},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.16770},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Weak Decays of the Λ_b Baryon in Light-Front Dynamics
AU - Chong-Chung Lih
AU - Cong-Yu Li
AU - Chao-Qiang Geng
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.16770
UR - https://arxiv.org/abs/2609.16770
AB - We investigate the exclusive semileptonic and nonleptonic Λ_b → Λ_c(p) decays within the Standard Model by using the light-front quark model. To determine the behavior of the Λ_b → Λ_c(p) transition form factors, we employ the Bethe-Salpeter formalism in the timelike region, effectively accounting for both valence and nonvalence contributions. Using these form factors, including nonvalence contributions, we obtain branching fractions of Λ_b → Λ_c ℓ ν̅_ℓ, Λ_b → Λ_c τ ν̅_τ, Λ_b → p ℓ ν̅_ℓ and Λ_b → p τ ν̅_τ~(ℓ=e or μ) are found to be around 5.39%, 1.41%, 3.33× 10^−4 and 2.08× 10^−4, respectively, which are consistent with the experimental measurements. The ratios of R^ℓτ(Λ_c)=(cal B(Λ_b→ Λ_c τ ν̅_τ))/(cal B(Λ_b→ Λ_c ℓ ν̅_l)) and R^ℓτ(p)=(cal B(Λ_b→ p τ ν̅_τ))/(cal B(Λ_b→ p ℓ ν̅_l)), are given by 0.261^+0.097_−0.117 and 0.624^+0.119_−0.129, respectively. The forward-backward asymmetries in the above semilepton decays are also examined. Our results indicate that, within the light-front framework, the nonvalence contributions to the asymmetries are negligible compared to the β-induced uncertainties. In addition, we calculate the branching ratios for the nonleptonic decays of Λ_b→ Λ_c(p) M with M being the pseudo scalar and vector mesons with the results found to be consistent with the current experimental data.
ER -