Semileptonic Decay of Λb → N(1520)⁻ν̄_ from QCD Light-cone Sum Rules

We investigate the complete set of vector and axial-vector form factors for the charged-current transition Λb⁰→ N(1520)⁺ using QCD light-cone sum rules (LCSRs) based on the light-cone distribution amplitudes (LCDAs) of the Λb baryon, with the hard-scattering kernels evaluated at tree level. In the hadronic representation of the correlation function, we include the pole contributions of both the negative-parity $N(1520)$, with JP=3/2⁻, and the positive-parity $N(1720)$, with JP=3/2⁺. By matching a selected set of Lorentz structures, we derive sum rules that separate the $N(1520)$ contribution from the $N(1720)$ contribution within the adopted two-pole hadronic ansatz. After extrapolating the large-recoil LCSR results over the physical q² region using a pole-improved z expansion truncated at linear order, we predict the differential branching fractions, the lepton forward-backward asymmetry, the charged-lepton polarization, and the $N(1520)$ polarization in Λb⁰→ N(1520)⁺⁻ν̄_ (=e,μ,τ). The corresponding total branching fractions are Be,μ,τ =(12.4±10.5,\,12.4±10.5,\,5.0±4.3)×10⁻⁵. Within the stated approximations, these results may serve as theoretical benchmarks for future experimental studies of this channel. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.