Sum rules for 1/m corrections to the form factors of semileptonic B decays

TL;DR

This paper derives sum rules for 1/m corrections to semileptonic B decay form factors using QCD sum rules, confirming theoretical patterns and providing numerical estimates of correction sizes.

Contribution

It introduces sum rules for subleading form factors in B decays from QCD sum rules, respecting HQET patterns and Luke's theorem.

Findings

1/m_c corrections are sizable but manageable.

Results align with HQET expectations.

Sum rules provide quantitative estimates of form factor corrections.

Abstract

Semileptonic B decays are described by the Isgur-Wise form factor to the leading order in 1/m; four new functions appear in the first order [Luke]. Values of these functions are crucial for the applicability of the whole approach to processes involving c quark. We obtain the sum rules for three subleading form factors from the QCD sum rules with finite masses by expanding to the first order in 1/m. The results respect the pattern of the first 1/m corrections established in HQET, and obey the Luke's theorem. The numerical estimates show that 1/m_c corrections are sizable but not catastrophic.