NRQCD and Static Systems -- A General Variational Approach

TL;DR

This paper introduces a variational Monte Carlo approach to study static and NRQCD mesons, demonstrating effective extraction of ground and excited state properties relevant to decay constants.

Contribution

It applies a novel variational technique with a large basis of operators to improve the analysis of static and NRQCD mesons in lattice simulations.

Findings

Good plateaus for ground state energies

Clear extraction of wave functions

Effective method for excited states

Abstract

We present initial results from Monte Carlo simulations of NRQCD-light, static-light, and NRQCD-NRQCD mesons, using a variational technique (MOST), as part of our ongoing calculation of the $f_{B}$ decay constant. The basis states for the variational calculation are quark-antiquark operators separated by all possible relative distances not equivalent under the cubic group (for example, for a $20^{3}$ lattice there are 286 operators). The efficacy of the method is demonstrated by the good plateaus obtained for the ground state and the clean extraction of the wave functions of the ground and first radially excited state.