Heavy quark expansion in 1/\hat{m}_Q and |V_cb| extraction

Abstract

The dressed heavy quark mass mQ = m Q + ¯ with ¯ being the binding energy is introduced to characterize the heavy hadrons containing a single heavy quark. A heavy quark expansion in terms of the inverse of the dressed heavy quark mass 1/ mQ is presented with a complete decomposition of the full field and integrating out the small components. The heavy quark-antiquark coupling effects are included in the finite mass corrections. It is shown that the 1/ mQ expansion is more favorable in application. The extraction of |V cb | from exclusive B decays is studied by using such a new expansion approach.

The 10 keV injector for the University of Maryland Electron Ring Project

“…Analytic calculation of grid effects produces a total expected emittance of 4 mm-mrad. While previous experience with the 2.5-keV gun indicates emittance growth of up to 80% [3] above the thermal emittance, the specification for the 10-keV injector allows for emittance growth of up to 280%. This should be easily achievable.…”

“…The electron gun is similar to a 2.5 keV gun used at the University of Maryland for some years [3]. It employs a conventional Pierce geometry and has a control grid located at 0.15 mm from an 8-mm diameter dispenser cathode.…”