Form Factors for Lambda_b -> Lambda Transitions in SCET

TL;DR

This paper analyzes Lambda_b to Lambda transition form factors using SCET, calculating a universal soft form factor via sum rules, including leading corrections, and providing numerical estimates relevant for decay observables.

Contribution

It introduces a systematic SCET-based method to compute Lambda_b to Lambda form factors, including corrections, with numerical estimates for decay processes.

Findings

Calculated the universal soft form factor using sum rules.

Derived leading corrections from hard-collinear gluon exchange.

Provided numerical estimates for form factors and decay observables.

Abstract

We present a systematic discussion of Lambda_b -> Lambda transition form factors in the framework of soft-collinear effective theory (SCET). The universal soft form factor, which enters the symmetry relations in the limit of large recoil energy, is calculated from a sum-rule analysis of a suitable SCET correlation function. The same method is applied to derive the leading corrections from hard-collinear gluon exchange at first order in the strong coupling constant. We present numerical estimates for form factors and form-factor ratios and their impact on decay observables in Lambda_b -> Lambda mu^+ mu^- decays.