The semileptonic decay within the LCSR approach under heavy quark effective field theory * * Supported in part by the Natural Science Foundation of China (11625520, 11765007, 11375008, 11647307, 11847301), the Project of Guizhou Provincial Department of Science and Technology ([2017]1089), and the Key Project for Innovation Research Groups of Guizhou Provincial Department of Education (KY[2016]028)

Abstract

The heavy quark effective field theory (HQEFT) provides an effective way to deal with heavy meson decays. In this paper, we adopt two different correlators to derive the light-cone sum rules (LCSR) for the transition form factors (TFFs) in the framework of HQEFT. We label the two LCSR results as LCSR- and LCSR- , which stand for the conventional correlator and the right-handed correlator. We observe that the correlation parameter for the branching ratio is , implying a consistency of LCSRs with the other correlators. Furthermore, we obtain and . We also obtain and , both of which agree with the lattice QCD predictions. Thus, HQEFT provides a useful framework for studying B meson decays. Moreover, by using the right-handed correlator, the twist-2 terms are dominant in TFF , as their contribution is over ~97% in the whole region, while the large twist-3 uncertainty of the conventional correlator is greatly suppressed. Hence, the LCSR- predictions can be used to test the properties of the various models for the pion twist-2 distribution amplitudes.