Karlsruhe 2011 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 8: Eingeladene Vorträge III
T 8.3: Eingeladener Vortrag
Donnerstag, 31. März 2011, 15:00–15:30, 30.21: 001
Non-perturbative Heavy Quark Effective Theory on the lattice — •Michele Della Morte — Institut fuer Kernphysik, Becherweg 45, Mainz
The b-quark is too heavy to be treated dynamically on the lattice. Indeed, in units of nowadays affordable resolutions amb >> 1. A theoretically attractive option is to use effective theories like Heavy Quark Effective Theory (HQET), which provides the correct asymptotic description of QCD correlation functions in the limit mb → ∞. Subleading effects are described by higher dimensional operators whose coupling constants are formally O(1/mb) to the appropriate power. The degrees of freedom in the effective theory are strongly coupled and therefore a non-perturbative approach is needed. In addition HQET has to be matched to the full theory, a step, which must as well be performed non-perturbatively beyond leading order in 1/mb.
A framework for non-perturbative HQET on the lattice has been recently introduced. In a first step we match HQET and QCD in a small volume (L=0.4 fm). To make contact with phenomenology the HQET expressions of the relevant quantities are then evolved to large volume. The essential tools in this step are the step scaling functions, which we introduce to describe the effects of a change in the linear size L of the system by a factor two. We present non-perturbative results at NLO in 1/mb for the b-quark mass, the Bs spectrum and decay constant in the quenched approximation and with two dynamical flavors.