Mainz 2012 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 54: Hadronenstruktur und -spektroskopie

HK 54.4: Talk

Friday, March 23, 2012, 12:00–12:15, RW 1

Central and spin-spin heavy-quark potentials from QCD — •Alexander Laschka, Norbert Kaiser, and Wolfram Weise — Physik Department, Technische Universität München, D-85747 Garching, Germany

Potential models with several free parameters have been used in the past to reproduce the experimentally observed charmonium and bottomonium spectra. Nowadays heavy-quark potentials can be derived in QCD from first principles. The spin-dependent heavy-quark potential, necessary to describe the hyperfine splittings, has been studied recently in a new lattice QCD approach. We show that the spin-spin potential, as well as the central potential, can be extended to short distances by matching the lattice results to the corresponding potentials derived in perturbative QCD. These matched potentials have only a single free parameter, an overall additive constant, and can be used to calculate quarkonium spectra. We find that the empirical hyperfine splittings in the ground states of charmonium and bottomonium can be accurately reproduced. Furthermore, we extract values for the charm and bottom quark masses and compare to other mass schemes.

Work supported in part by BMBF, GSI and by the DFG Excellence Cluster “Origin and Structure of the Universe”.