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), lambda B in heavy quark effective theory, using form factor estimates from Lattice QCD collaboration. The estimation of the parameter lambda B 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 lambda 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 lambda B=338+-68 MeV, when the B-meson LCDAs are expressed in the Exponential model. Additionally, we compare the form factor predictions, using the constrained lambda B value, with the earlier analyses for other channels as well, such as B--> pie and B-->D.