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HK: Hadronen und Kerne

HK 37: Hadronic Probes IV, Interaction of Pions

HK 37.1: Group Report

Tuesday, March 17, 1998, 17:00–17:30, C

A dispersive analysis of ππ scattering — •Paul Büttiker and Balasubramanian Ananthanarayan — FZ Jülich, IKP (Th) und CTS, IISC, Bangalore (India)

ππ scattering is an important process to test the predictions of chiral perturbation theory (ChPT). ChPT is a non-renormalizable theory and involves additional coupling constants at each order of the derivative or momentum expansion. This process has been studied in great detail in axiomatic field theory. From dispersion relations, the Roy equations, a set of coupled integral equations for the ππ partial waves, have been established [1]. These equations have been used to derive sum rules for the threshold parameters of ππ scattering [2,3], which, in turn, are functions of the coupling constants in the chiral framework. We estimate those quantities for which there is no information available in the literature. A comparison of the two descriptions can be regarded as a probe into the range of validity in energy of chiral predictions. Furthermore, we report on a direct determination of two chiral coupling constants by performing a Roy equation fit to the experimental phase shift data [4].

[1] S. M. Roy, Phys. Lett. B 36 (1971) 353.

[2] B. Ananthanarayan and P. Büttiker, hep-ph/9707305, Phys. Lett. B (in print).

[3] B. Ananthanarayan and P. Büttiker, Phys. Rev. D 54, 5501 (1996).

[4] B. Ananthanarayan and P. Büttiker, Phys. Rev. D 54, 1125 (1996).