Update on Quarkonium Spectroscopy and $\hat{I}{\pm }_{strong}$ from NRQCD

Abstract

NRQCD results for Upsilon and Charmonium using both dynamical and quenched configurations are presented. We investigate dependence on the light dynamical quark mass. Preliminary dynamical ($n_f=2$) Charmonium data are combined with quenched results to extract the strong coupling constant $\hat{I}{\pm }_P^{(n_f)}$ for the physical number of light dynamical quarks, $n_f=3$. Good agreement is found with calculations based on the Upsilon system. We show that a discrepancy in $\hat{I}{\pm }_P^{(n_f=0)}$, found between the Upsilon and Charmonium systems in the quenched theory, disappears upon extrapolating to the physical number of flavors. Results for the strong coupling constant $\hat{I}{\pm }_{\overline{MS}}$ are presented and sources of systematic error investigated.

8 pages of tex with 2 uuencoded postscript figures. Contribution to LAT95