Dispersion relations and the Δ contributions into the amplitudes M₁₊^3/2,E₁₊^3/2 from new VPI partial-wave analysis of pion photoproduction

1999/04/08 by I. G. Aznauryan, Aznauryan, I. G.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph

paper · pdf · doi:10.48550/arxiv.hep-ph/9904275

8 pages, 2 figures

arxiv created 1999/04/08 · arxiv updated 2009/11/30

Abstract

Within fixed-t dispersion relations the results of new VPI partial-wave analysis for the multipole amplitudes M₁₊^3/2,E₁₊^3/2 are successfuly described, and the resonance and nonresonance contributions into these amplitudes are separated in correspondence with the interpretation on the language of diagram approach, dynamical models and effective Lagrangian approach. The amplitudes A_p^3/2 and A_p^1/2 corresponding to the Δ contributions into M₁₊^3/2,E₁₊^3/2 are obtained. They are in better agreement with quark model predictions than the amplitudes extracted without subtraction of the nonresonance contributions in M₁₊^3/2,E₁₊^3/2. The obtained value of the ratio E2/M1 for the γN → P₃₃(1232) transition is: E2/M1=-0.022± 0.004.

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