Lambda _b rightarrow p, N^*(1535) form factors from QCD light-cone sum rules

Abstract

In this work, we calculate the transition form factors of Lambda _b decaying into proton and N^*(1535) (J^P={1/2}^+ and {1/2}^- respectively) within the framework of light-cone sum rules with the distribution amplitudes (DAs) of Lambda _b-baryon. In the hadronic representation of the correlation function, we have isolated both the proton and the N^*(1535) states so that the Lambda _b rightarrow p, N^*(1535) form factors can be evaluated simultaneously. Due to the less known properties of the baryons, we investigate three interpolating currents of the light baryons and five parametrization models for DAs of Lambda _b . Numerically, our predictions on the Lambda _b rightarrow p form factors and the branching fractions of Lambda _brightarrow pell nu from the Ioffe or the tensor currents are consistent with the Lattice simulation and the results from the light-baryon sum rules, as well as the experimental data of Br(Lambda _b^0rightarrow pmu ^-{{bar{nu }}}). The predictions on the form factors of Lambda _b rightarrow N^*(1535) are very sensitive to the choice of the interpolating currents so that the relevant measurement could be helpful to clarify the properties of baryons.