منابع مشابه
Butp-98/22 Ππ Scattering at Low Energy: Status Report ∗)
I discuss the status of ongoing work to determine numerically the elastic ππ scattering amplitude at order p 6 in the framework of chiral perturbation theory.
متن کاملHigher Threshold Parameters in ππ Scattering
A family of threshold parameters which probe the stability of chiral predictions is considered. The relevant criteria for the choice of threshold parameters are discussed. Sum rules for these quantities are derived from dispersion relations and evaluated from effective range formulae. Good agreement with two-loop chiral estimates for many of these quantities is found and interesting discrepanci...
متن کاملScattering Lengths and Medium and High Energy ππ Scattering
Medium and high energy absorptive parts contribute to dispersive expressions for Dwave scattering lengths, a2 and a 2 2. For the model employed by Basdevant, Frogatt and Peterson we find the Dwave driving term contributions to the Dwave scattering lengths are 1.8 · 10−4 to a2 and 0.4 · 10 −4 to a2, roughly 10% and 30% of their respective central experimental values. Inequivalent sets of sum rul...
متن کاملΠπ Scattering
We demonstrate that, together with the available experimental information , chiral symmetry determines the low energy behaviour of the ππ scattering amplitude to within very small uncertainties. In particular, the threshold parameters of the S–, P –, D– and F –waves are predicted, as well as the mass and width of the ρ and of the broad bump in the S–wave. The implications for the coupling const...
متن کاملDetermination of Two-Loop ππ Scattering Amplitude Parameters
The chiral expansion of the ππ amplitude to the order of two loops was expressed in terms of six independent parameters in a previous paper: four of these are shown here to satisfy sum rules. Their derivation, where crossing symmetry plays a key role, is explained. Their convergence properties are studied and their practical evaluation, in terms of the available data on ππ phase shifts above 0....
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ژورنال
عنوان ژورنال: Il Nuovo Cimento A
سال: 1974
ISSN: 0369-3546,1826-9869
DOI: 10.1007/bf02801850