Chiral Extrapolation of Lattice Data of Λb →Λc Form Factors

Abstract

An extrapolation to the physical limit for the lattice data of Λb →Λc form factors computed in the nonphysical region is made in this work through a class of fitting functions proposed by us with nonlinear dependence on derived in the chiral perturbative theory (ChPT) and the heavy quark effective theory (HQET) framework. Then the results are applied to calculate the differential and integrated Λb →Λc semileptonic decay rates. Meanwhile, a comparison between our results and those obtained through the extrapolation functions with naive linear dependence on is made. It is shown that the difference between the extrapolated central values of these two cases is about 5%. The total uncertainties (depending on the momentum transfer q2) in the linear case are about 5% ∼ 10% (caused by the uncertainties of lattice data) and those in the nonlinear case are about 10% ∼ 20% (caused by the uncertainties of both lattice data and input parameters in ChPT and HQET). More accurate lattice data and parameters in ChPT and HQET are needed to reduce the uncertainties of the extrapolated results.