Light-cone sum rule analysis of semileptonic decays $$\varLambda _b^0 \rightarrow \varLambda _c^+ \ell ^- {\overline{\nu }}_\ell $$

Abstract

AbstractIn this work, we analyze the semileptonic decay processes of $$\varLambda _b \rightarrow \varLambda _c$$ Λ b → Λ c in the light-cone sum rule approach. In order to calculate the form factors of the $$\varLambda _b$$ Λ b baryon transition matrix element, we use the light-cone distribution amplitudes of $$\varLambda _b$$ Λ b obtained from the QCD sum rule in the heavy quark effective field theory framework. With the calculation of the six form factors of the $$\varLambda _b \rightarrow \varLambda _c$$ Λ b → Λ c transition matrix element, the differential decay widths of $$\varLambda _b^0 \rightarrow \varLambda _c^+ \ell ^- {\overline{\nu }}_\ell (\ell = e, ~\mu , ~\tau )$$ Λ b 0 → Λ c + ℓ - ν ¯ ℓ ( ℓ = e , μ , τ ) and their absolute branching fractions are obtained. Additionally, the ratio of $$R(\varLambda _c^+) \equiv {\mathcal {B}}r(\varLambda _b^0 \rightarrow \varLambda _c^+ \tau ^- {\overline{\nu }}_\tau )/{\mathcal {B}}r(\varLambda _b^0 \rightarrow \varLambda _c^+ \mu ^- {\overline{\nu }}_\mu )$$ R ( Λ c + ) ≡ B r ( Λ b 0 → Λ c + τ - ν ¯ τ ) / B r ( Λ b 0 → Λ c + μ - ν ¯ μ ) is also obtained in this work. Our results are in accord with the newest experimental result and other theoretical calculations and predictions.