Constraining inverse moment of B-meson distribution amplitude using lattice QCD data

Abstract

We constrain the inverse moment of the B-meson light-cone distribution amplitude (LCDA), λB in heavy quark effective theory, using form factor estimates from Lattice QCD collaboration. The estimation of the parameter λB has, until now, relied solely on QCD sum rule methods and deals with significant uncertainty. In this work, we express the form factors for the B -> K channel, calculated within the light-cone sum rule (LCSR) approach, in terms of the B meson LCDAs. By incorporating recent Lattice results from the HPQCD collaboration for the B → K form factors at zero momentum transfer (q2 = 0), we impose constraints on this parameter. Consequently, we achieve a twofold reduction in uncertainty compared to the QCD sum rule estimate, yielding λB=338+68MeV, when the B-meson LCDAs are expressed in the Exponential model. Additionally, we compare the form factor predictions, using the constrained λB value, with the earlier analyses for other channels as well, such as B→π and B→D.