Update on Quarkonium Spectroscopy and $α_{strong}$ from NRQCD

Davies, C. T. H.; Hornbostel, K.; Lepage, G. P.; Lidsey, A. J.; McCallum, P.; Shigemitsu, J.; Sloan, J.

Update on Quarkonium Spectroscopy and $α_{strong}$ from NRQCD

Authors

Description

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 $α_P^{(n_f)}$ 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 $α_P^{(n_f=0)}$, 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 $α_{\overline{MS}}$ are presented and sources of systematic error investigated.
8 pages of tex with 2 uuencoded postscript figures. Contribution to LAT95