Gießen 2007 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 42: Theorie

HK 42.5: Vortrag

Donnerstag, 15. März 2007, 12:15–12:30, C

Quarkonium spectra beyond one-gluon exchange — •Johannes Eiglsperger, Wolfram Weise, and Norbert Kaiser — Institut für theoretische Physik (T39), TU München, Germany

We study the spectra of charmonium and bottomonium in an improved potential model. Besides the one-gluon exchange and a linear confinement potential we include systematically effects from two-gluon exchange (∼α_s²) and the t-channel exchange of qq-bound states. We find that the empirical spectra of cc and bb can be well reproduced with parameters (quark masses m_c and m_b, strong coupling constant α_s and stringtension σ) consistent with lattice simulations and QCD-determinations. The two-gluon exchange together with the induced qq-interaction is essential in order to reproduce quantitatively the fine- and hyperfine-splittings.