Transition form factors and angular distributions of the $\bm{Λ_b\toΛ(1520)(\to N\bar{K})\ell^+\ell^-}$ decay supported by baryon spectroscopy

Abstract

We calculate the weak transition form factors of the $Λ_b\toΛ(1520)$ transition, and further calculate the angular distributions of the rare decays $Λ_b\toΛ(1520)(\to N\bar{K})\ell^{+}\ell^{-}$ ($N\bar{K}=\{pK^-,n\bar{K}^0\}$) with unpolarized $Λ_b$ and massive leptons. The form factors are calculated by the three-body light-front quark model with the support of numerical wave functions of $Λ_b$ and $Λ(1520)$ from solving the semirelativistic potential model associated with the Gaussian expansion method. By fitting the mass spectrum of the observed single bottom and charmed baryons, the parameters of the potential model are fixed, so this strategy can avoid the uncertainties arising from the choice of a simple harmonic oscillator wave function of the baryons. With more data accumulated in the LHCb experiment, our result can help for exploring the $Λ_b\toΛ(1520)\ell^+\ell^-$ decay and deepen our understanding on the $b\to s\ell^+\ell^-$ processes.