Bounds on Heavy-to-Heavy Baryonic Form Factors

TL;DR

This paper derives bounds on Lambda_b to Lambda_c semileptonic decay form factors using heavy-quark-effective-theory sum rules, providing theoretical constraints and comparing them with existing models.

Contribution

It introduces new bounds on decay form factors based on sum rules, including higher-order corrections, and compares these bounds with current models.

Findings

Bounds are established at leading order in Lambda_QCD/m_Q and alpha_s.

O(alpha_s^2 beta_0) corrections at zero recoil are calculated.

Comparison shows some models are consistent with the bounds.

Abstract

Upper and lower bounds are established on the Lambda_b -> Lambda_c semileptonic decay form factors by utilizing inclusive heavy-quark-effective-theory sum rules. These bounds are calculated to leading order in Lambda_QCD/m_Q and alpha_s. The O(alpha_s^2 beta_0) corrections to the bounds at zero recoil are also presented. Several form factor models used in the literature are compared with our bounds.