NRQCD Calculations of Heavy Quark Bound States: Focus on the Fine Structure

Texas Tech University, Lubbock TX

Investigators

Abstract

In recent years great strides have been made in lattice quantum chromodynamics (LQCD) from tadpole improvement and improved discretizations1 to simulations that include up to three flavors of dynamical quarks. It is possible to use coarser lattices than previously thought, decreasing the cost of simulations by as much as a factor of 10. In addition to a decrease in the cost of simulations, the time required for lattice simulations has also significantly decreased, the simplest calculations can now be done on a personal computer. Most importantly, it is now possible to perform high precision LQCD calculations, often with errors on the order of 1% or less, that can be used to test QCD and to predict experimental results. The implications of these new techniques are of particular importance to heavy quark physics. This project focuses on precision LQCD calculations of experimentally measurable quantities and to extending to higher order in powers of v/c knowledge of the non-relativistic QCD (NRQCD) Lagrangian that can be used in other calculations. The project involves collaboration with members of the high precision quantum chromodynamics (HPQCD) and United Kingdom quantum chromodynamics (UKQCD) collaborations and will focus on NRQCD calculations of heavy quark bound states, in particular, on the fine structure of the Upsilon meson which is a bound state of a bottom quark and a bottom anti-quark