Bounds on Heavy-to-Heavy Mesonic Form Factors

TL;DR

This paper derives theoretical bounds on B to D and D* mesonic form factors using heavy quark effective theory sum rules, including higher-order corrections, and compares these bounds with existing models.

Contribution

It introduces new bounds on heavy-to-heavy mesonic form factors incorporating higher-order QCD corrections and evaluates their consistency with current models.

Findings

Most models do not satisfy the derived bounds.

Bounds are computed at leading order and include second-order alpha_s corrections.

The bounds provide constraints for future form factor modeling.

Abstract

We provide upper and lower bounds on the form factors for B -> D, D^* 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. We compare our bounds with some of the form factor models used in the literature. All the models we investigated failed to fall within the bounds for the combination of form factors (omega^2 - 1)/(4 omega)|omega h_{A2}+h_{A3}|^2.