Model for nonleptonic and semileptonic decays by (B)over-bar0 → D**-transitions with BR(j=1/2) << BR(j=3/2) using the Leibovich-Ligeti-Stewart-Wise scheme

We present a model for the vector and axial form factors of the transitions (B) over bar (0) -> D** in good agreement with the presently available data and based on the present theoretical knowledge, combining (a) the safe lattice QCD predictions at m(Q) = infinity and w = 1; (b) the predictions at general w of a relativistic, covariant quark model at m(Q) = infinity, including the well-tested Godfrey and Isgur spectroscopic model and which agrees with lattice QCD at w = 1; (c) the constraint of Bjorken and Neubert relating semileptonic and class I nonleptonic decays, which shows that (B) over bar (0) -> D-0(2300)(+)pi(-) strongly constrains tau(1/2)(w) to be much smaller than tau(3/2)(w), in agreement with the theoretical expectation; and (d) the general HQET expansion which constrains the 1/m(Q) corrections (cf. Leibovich et al. Phys. Rev. Lett. 78, 3995 (1997)., denoted hereafter as LLSW). An important element in the understanding of data is the large contribution of virtual V to the broad structures seen in SL decays at low D-(*)pi masses-which makes it difficult to isolate the broad resonances denoted as D-1/2 in the following.

Automated summary

The model presented for the vector and axial form factors of the transitions (B) over bar (0) -> D** is based on lattice QCD predictions, relativistic quark model predictions, constraints, and HQET expansion. It aims to explain the data on (B) over bar (0) -> D** transitions, especially focusing on the broad structures seen at low D-(*)pi masses.