Precision $\Upsilon$ Spectroscopy and Fundamental Parameters From NRQCD

TL;DR

This paper reports high-precision lattice NRQCD simulations of the bottomonium system, improving techniques and providing new determinations of fundamental Standard Model parameters like alpha_s and M_b.

Contribution

It introduces advanced lattice techniques and offers new, precise measurements of alpha_s(M_Z) and M_b from quenched NRQCD simulations of the Upsilon system.

Findings

Demonstrated perturbative improvement of lattice actions

Achieved high-precision determinations of alpha_s(M_Z) and M_b

Developed multicorrelated fits for excited state spectra

Abstract

We present results from a high precision NRQCD simulation of the quenched $\Upsilon$ system at $\beta = 6$. We demonstrate a variety of important lattice techniques, including the perturbative improvement of actions, tadpole improvement, and multicorrelated fits for extracting the spectrum of excited states. We present new determinations of $\alpha_s(M_Z)$ and $M_b$, two fundamental parameters of the Standard Model.