M. A. Moinester

Measurement of the πmeson polarizabilities via the γp → γπ + n reaction

Abstract.An experiment on the radiative π{+}-meson photoproduction from the proton ( γp → γπ{+}n) was carried out at the Mainz Microtron MAMI in the kinematic region 537MeV < Eγ < 817MeV, 140°≤

Chiral symmetry and pion polarizabilities

\theta_{{\gamma \gamma ^{\prime }}}^{{{{\rm cm}}}}

Design, construction, and performance of a high-resolution π0 spectrometer for nuclear physics experiments

≤180°. The π{+}-meson polarizabilities have been determined from a comparison of the data with the predictions of two different theoretical models, the first one being based on an effective pole model with pseudoscalar coupling while the second one is based on diagrams describing both resonant and nonresonant contributions. The validity of the models has been verified by comparing the predictions with the present experimental data in the kinematic region where the pion polarizability contribution is negligible ( s1 < 5mπ2) and where the difference between the predictions of the two models does not exceed 3%. In the region, where the pion polarizability contribution is substantial ( 5 < s1/mπ2 < 15, -12 < t/mπ2 < - 2), the difference

The (n, p) reaction as a probe of Gamow-Teller strength

\ensuremath{(\alpha -\beta )_{\pi^{+}}}

The structure of 36Ar and 38Ar via the (3He, d) reaction on 35Cl and 37Cl

of the electric (α) and the magnetic (β) polarizabilities has been determined. As a result we find

High momentum transfer longitudinal and transverse form factors of the 7Li ground-state doublet

\ensuremath{(\alpha -\beta )_{\pi^{+}}=(11.6\pm 1.5_{{\rm stat}}\pm 3.0_{{\rm syst}}\pm 0.5_{{\rm mod}})\times 10^{-4}{}{\rm fm^{3}}}

Gamow-Teller strength and giant resonances in 90Zr(n,p) at 198 MeV☆

. This result is at variance with recent calculations in the framework of chiral perturbation theory.

Neutron hole states in 91Mo and 93Mo studied by the (p, d) reaction

Abstract We use chiral perturbation theory including one-loop contribution to derive formulae needed to deduce pion polarizabilities for γπ→γπ and γγ→ππ data. We deduce for the first time values for the π± and π0 polarizabilities from ππ production data, and compare these new results to chiral symmetry predictions.

Electromagnetic matrix elements in baryons

Abstract A spectrometer for the detection of neutral pions in nuclear physics research was designed, constructed, and tested at the Los Alamos Meson Physics Facility. It is capable of detecting neutral pions with high efficiency, and with a fwhm energy resolution of 2 MeV with a typical acceptance of 1 msr. In the first experiment in which the spectrometer was used, its performance was evaluated, and nuclear physics research, based on the detection of neutral pions, was performed.

Charge and transition densities of samarium isotopes in the interacting boson modei

Abstract The ground state differential cross sections for the (n, p) reaction at 0° on 6 Li, 12 C and 13 C have been measured for 198 MeV neutrons with a precision of about 4% relative to the corresponding value for the H(n, p) reaction. These data, together with the accurately known ft values for the β- decay of 6 He, 12 B and 13 B provide three calibrations of the (n, p) reaction as a probe of Gamow-Teller strength for isospin raising transitions.