# HEP/Astro Seminar, Thursday 16th April 1998

## Ben Grinstein (U. California, San Diego)




### Abstract

We present a method for parametrizing heavy meson semileptonic form
factors using dispersion relations, and from it produce a
two-parameter description of the B -> B elastic form factor. We use
heavy quark symmetry to relate this function to B->D* l \nu form
factors, and extract |V_{cb}|=0.037^{+0.003}_{-0.002} from
experimental data with a least squares fit. Our method eliminates
model-dependent uncertainties inherent in choosing a parametrization
for the extrapolation of the differential decay rate to threshold. The
method also allows a description of B -> D l nu form factors accurate
to 1% in terms of two parameters.



## Thursday, 3:30pm, Smith Lab 4079

Francesco Antonuccio ( anton@pacific.mps.ohio-state.edu), last updated 30-MAR-98.