Heavy Quark Expansion in 1/\hat{m}_Q and |V_{cb}| Extraction

TL;DR

This paper introduces a new heavy quark expansion based on the dressed heavy quark mass to improve the extraction of |V_{cb}| from B meson decays, accounting for finite mass effects more effectively.

Contribution

It presents a novel heavy quark expansion in terms of the inverse dressed mass, including coupling effects, and applies it to extract |V_{cb}| more accurately.

Findings

The 1/hat{m}_Q expansion is more advantageous for practical applications.

Finite mass corrections include heavy quark-antiquark coupling effects.

The new approach improves the precision of |V_{cb}| extraction from B decays.

Abstract

The dressed heavy quark mass \hat{m}_Q=m_Q+\bar{{\Lambda}} with \bar{{\Lambda}} being the binding energy is introduced to characterize the heavy hadrons containing a single heavy quark. A heavy quark expansion in terms of the inverse of the dressed heavy quark mass 1/\hat{m}_Q is presented with a complete decomposition of the full field and integrating out the small components. The heavy quark-antiquark coupling effects are included in the finite mass corrections. It is shown that the 1/\hat{m}_Q expansion is more favorable in application. The extraction of |V_{cb}| from exclusive B decays is studied by using such a new expansion approach.