B. F. Gibson

Toward a resolution of the neutron-neutron scattering-length issue

Abstract We report a high-precision determination of the 1 S 0 neutron–neutron scattering length ( a nn ) using the 2 H( π − , nγ ) n reaction. The value obtained in the present work is −18.50± 0.05 (statistical) ± 0.44 (systematic) ± 0.30 (theoretical) fm, which is consistent with the values from previous measurements. Combining our result with previous measurements reduces the total uncertainty in the world average of a nn to ±0.4 fm, matching the accuracy to which the charge-symmetric parameter a pp is determined.

Scaling relations for triton ground-state observables

Abstract Using a wide variety of newly obtained solutions to the Feddeev equations for the triton ground state with diverse two-body and three-body potentials, we have calculated Coulomb energies, RMS charge radii, binding energies, and probabilities of various wave function components. We show how the various radii scale with the corresponding binding energies, and advance simple arguments for the sizes of various wave function components. The Coulomb energies are compared to the hyperspherical approximation, which is found to be very accurate. In addition to our quantitative conclusions, we provide very simple qualitative arguments which account for these conclusions. Comparisons with experimental data are made where applicable.

Parity-Violating Interaction Effects I: The Longitudinal Asymmetry in pp Elastic Scattering

The proton-proton parity-violating longitudinal asymmetry is calculated in the lab-energy range 0--350 MeV, using a number of different, latest-generation strong-interaction potentials--Argonne {nu}{sub 18}, Bonn-2000, and Nijmegen-I--in combination with a weak-interaction potential consisting of rho- and omega-meson exchanges--the model known as DDH. The complete scattering problem in the presence of parity-conserving, including Coulomb, and parity-violating potentials is solved in both configuration- and momentum-space. The predicted parity-violating asymmetries are found to be only weakly dependent upon the input strong-interaction potential adopted in the calculation. Values for the rho- and omega-meson weak coupling constants h{sub {rho}}{sup pp} and h{sub {omega}}{sup pp} are determined by reproducing the measured asymmetries at 13.6 MeV, 45 MeV, and 221 MeV.

Thermal n-d radiative capture

Abstract The impulse-approximation and pion-exchange current contributions to the radiative capture of thermal neutrons by deuterium have been calculated using initial- and final-state wave functions generated by solving the configuration-space Faddeev equations for several nucleon-nucleon and nucleon-nucleon-plus-three-body-force hamiltonian models. Numerical results are compared with previously published total cross section data and with recent measurements of the M1 photon polarization and the spin-quartet capture fraction.

Three-body structure of the nn Lambda system with Lambda N - Sigma N coupling

The structure of the three-body

Three-body structure of the nnsystem withNN coupling

nn\Lambda

Isospin shift of the energy of the giant resonance

system, which has been observed recently by the HypHI collaboration, is investigated taking

Faddeev Monte-Carlo calculations of trinucleon binding energy with three-body potentials

\Lambda N-\Sigma N

Parity conserving γ asymmetry in n - p radiative capture

coupling explicitly into account. The

Anatomy of the soft photon approximation in hadron-hadron bremsstrahlung

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