A scheme based on the chiral Lagrangian, analyticity and unitarity is applied to spin observables in pion photoproduction and nucleon Compton scattering. Subthreshold partial-wave amplitudes are calculated in chiral perturbation theory and extrapolated beyond the threshold region imposing the micro-causality and the unitarity constraint. A reasonable description of various spin observables up to energies root s similar or equal to 1300 MeV is obtained in terms of the parameters relevant at order Q(3) in the chiral Lagrangian. Nucleon spin-polarizabilities predicted in our scheme are consistent with recent measurements of double polarization asymmetries at MAMI.
Spin Observables in Pion Photoproduction and Nucleon Compton Scattering from the Chiral Lagrangian and Dispersion Relations
PASQUINI, BARBARA
2016-01-01
Abstract
A scheme based on the chiral Lagrangian, analyticity and unitarity is applied to spin observables in pion photoproduction and nucleon Compton scattering. Subthreshold partial-wave amplitudes are calculated in chiral perturbation theory and extrapolated beyond the threshold region imposing the micro-causality and the unitarity constraint. A reasonable description of various spin observables up to energies root s similar or equal to 1300 MeV is obtained in terms of the parameters relevant at order Q(3) in the chiral Lagrangian. Nucleon spin-polarizabilities predicted in our scheme are consistent with recent measurements of double polarization asymmetries at MAMI.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
