The Isgur-Wise Function

TL;DR

This paper reviews the extraction of the Isgur-Wise function from lattice QCD calculations within HQET, testing heavy-quark symmetries and exploring direct computation methods for heavy-light meson decays.

Contribution

It summarizes recent lattice QCD methods for determining the Isgur-Wise function and discusses new approaches to compute it directly from HQET.

Findings

Testing of heavy-quark spin-flavour symmetries around the charm mass.

Indications of the size of $O(1/m_c)$ corrections.

Potential for direct lattice computation of the Isgur-Wise function.

Abstract

After a brief introduction to the Heavy-Quark Effective Theory (HQET), I review the extraction of the Isgur-Wise function from lattice QCD calculations of the matrix elements for semi-leptonic decays of heavy-light pseudoscalar mesons both into pseudoscalar and into vector mesons. This work is beginning to test the heavy-quark spin-flavour symmetries around the charm mass and to indicate the size of $O(1/m_c)$ corrections. An alternative approach to put the HQET on the lattice offers the prospect of computing the Isgur-Wise function directly.