Transition form factors of the $\Lambda_b \rightarrow \Lambda(1520)$ in QCD light-cone sum rules

TL;DR

This paper calculates the transition form factors for the decay of Lambda_b to Lambda(1520) using light-cone sum rules, providing predictions for decay observables that agree with experimental data.

Contribution

It introduces a method to unambiguously compute Lambda_b to Lambda(1520) form factors using light-cone sum rules with specific Lorentz structure selection.

Findings

Predicted differential branching fraction matches LHCb data.

Provided detailed decay observables including asymmetries and polarization.

Enhanced understanding of Lambda_b to Lambda(1520) transition dynamics.

Abstract

In this work, we investigate the transition form factors for $\Lambda_b\rightarrow{\Lambda(1520)}$ within the framework of light-cone sum rules (LCSR), using the light-cone distribution amplitudes (LCDAs) of the $\Lambda_b$-baryon. In the hadronic representation of the correlation function, we carefully select the appropriate Lorentz structures and isolate the contributions from both the $\Lambda(1520)(J^P=(3/2)^-)$ and the $\Lambda(1890)(J^P=(3/2)^+)$, ensuring that the form factors for $\Lambda_b\rightarrow{\Lambda(1520)}$ can be calculated unambiguously. We also provide predictions for various physical observables in the decay $\Lambda_b\rightarrow{\Lambda(1520)}l^+l^-$, including the differential branching fraction, the lepton-side forward-backward asymmetry, the longitudinal polarization fraction, and the CP-averaged normalized angular observable. Our prediction for the differential branching fraction of $\Lambda_b\rightarrow{\Lambda(1520)}\mu^+\mu^-$ is in good agreement with the LHCb measurement within the uncertainties.