3 research outputs found
Dispersive Bounds on the Shape of B -> D^(*) l nu Form Factors
Dispersive constraints on the shape of the form factors which describe the
exclusive decays B -> D^(*) l nu are derived by fully exploiting spin symmetry
in the ground-state doublet of heavy-light mesons. The analysis includes all
twenty B^(*) -> D^(*) semileptonic form factors. Heavy-quark symmetry, with
both short-distance and 1/m_Q corrections included, is used to provide
relations between the form factors near zero recoil. Simple one-parameter
functions are derived, which describe the form factors in the semileptonic
region with an accuracy of better than 2%. The implications of our results for
the determination of |V_cb| are discussed.Comment: 32 pages, 6 figure