| As bottom meson data accumulate, the importance of detailed theoretical knowledge of heavy-light meson properties and dynamics grows more pressing. In recent years, Heavy Quark Effective Theory has proven to be a most valuable tool for extricating the properties of hadrons containing a single heavy quark. In the heavy-quark limit, the unknown form factors for semileptonic B decay collapse into a single unknown function, the so-called Isgur-Wise function. We seek a careful balance between theoretical rigor and phenomenological usefulness. By combining data for the heavy-light wavefunction calculated on the lattice with the framework provided by HQET, we calculate the Isgur-Wise function in terms of a single measurable parameter—the slope of the function at zero-recoil. We obtain a simple analytic formula for the Isgur-Wise function. Making use of the observation that 1/m corrections to the heavy quark limit are small and approximately linear in the kinematic variable ω, we rewrite the physical form factors as Isgur-Wise functions with shifted slopes and intercepts. Thus, our analytic formula can be used to fit the semileptonic decay data, considerably simplifying the analysis.; In addition, we make several interesting observations regarding heavy-light dynamics, notably that the Nambu-Goto string spectroscopy is replicated in highly radially excited states of linear vector confinement. Using semiclassical methods, we obtain the energy spectrum in the radially-dominant regime ( E aJ) for a linear confining vector potential. For these deep radial excitations, the Regge slope, spacing between daughter trajectories and absolute state energies agree with those of the QCD string. Finally, we investigate the energy spectrum obtained from a vector confining potential plus an attractive Coulomb potential. |
