T. Michel

First measurement of the Gerasimov-Drell-Hearn integral for Hydrogen from 200 to 800 MeV

A direct measurement of the helicity dependence of the total photoabsorption cross section on the proton was carried out at MAMI (Mainz) in the energy range 200<E_gamma<800 MeV. The experiment used a 4

Helicity amplitudes A1/2 and A3/2 for the D13(1520) resonance obtained from the gamma-->p-->-->ppi(0) Reaction.

pi

Helicity dependence of the gamma p -> N pi channels and multipole analysis in the Delta region

detection system, a circularly polarized tagged photon beam and a frozen spin target. The contributions to the Gerasimov-Drell-Hearn sum rule and to the forward spin polarizability

Helicity dependence of the reaction in the second resonance region

gamma_0

First measurement of the Gerasimov-Drell-Hearn integral for 1 H from 200 to 800 MeV

determined from the data are 226 pm 5 (stat)pm 12(sys) mu b and -187 pm 8 (stat)pm 10(sys)10^{-6} fm^4, respectively, for 200<E_gamma<800 MeV.

The polarized electron beam at ELSA

The helicity dependence of the gamma-->p-->-->ppi(0) reaction has been measured for the first time in the photon-energy range from 550 to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam, and a longitudinally polarized frozen-spin target. These data are predominantly sensitive to the D13(1520) resonance and are used to determine its helicity amplitudes.

Helicity dependence of the γ→p→→nπ+π0 reaction in the second resonance region

Abstract.A high-quality double-polarization data set for the helicity dependence of the total and differential cross-sections for both

Helicity dependence of the gamma(pol.) p(pol.) --> n pi+ pi0 reaction in the second resonance region

gamma prightarrow N pi

Helicity dependence of the gamma p to n pi /sup +/ pi /sup 0/ reaction in the second resonance region

channels in the

Helicity AmplitudesA1/2andA3/2for theD13(1520)Resonance Obtained from theγ→p→→pπ0Reaction

Delta