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HK: Physik der Hadronen und Kerne

HK 26: Theorie III

HK 26.5: Vortrag

Mittwoch, 19. März 2003, 12:00–12:15, D

QCD sum rules in x-space — •Bernd-Jochen Schaefer¹ and Hilmar Forkel² — ¹TU Darmstadt, Schlossgartenstr. 9, D-64289 Darmstadt — ²Uni. Heidelberg, Philosophenweg 19, D-69120 Heidelberg

We explore a novel approach to QCD sum rules, based on matching the operator product expansion in spacetime to a suitably transformed dispersive representation containing the hadron parameters to be determined.

The use of x-space correlators makes this approach both more transparent and, due to the potential presence of non-singular contributions, more general than the usual one based on the Borel transform. Moreover, working in spacetime allows for a direct comparison with correlators obtained from other sources as, for example, lattice simulations. Nevertheless, the main benefits of the Borel transform carry over to the new sum rules.

We present results of the x-space sum rules in several meson channels, compare with the corresponding Borel sum rules, and discuss both conceptual and practical advantages and limitations of the new approach.