Benjamin F. Gibson

Model dependence of the 2H electric dipole moment

Background: Direct measurement of the electric dipole moment (EDM) of the neutron is in the future; measurement of a nuclear EDM may well come first. The deuteron is one nucleus for which exact model calculations are feasible. Purpose: We explore the model dependence of deuteron EDM calculations. Methods: Using a separable potential formulation of the Hamiltonian, we examine the sensitivity of the deuteron EDM to variation in the nucleon-nucleon interaction. We write the EDM as the sum of two terms, the first depending on the target wave function with plane-wave intermediate states, and the second depending on intermediate multiple scattering in the 3 P 1 channel, the latter being sensitive to the off-shell behavior of the 3 P 1 amplitude. Results: We compare the full calculation with the plane-wave approximation result, examine the tensor force contribution to the model results, and explore the effect of short-range repulsion found in realistic, contemporary potential models of the deuteron. Conclusions: Because one-pion exchange dominates the EDM calculation, separable potential model calculations will provide an adequate description of the 2 H EDM until such time as a measurement better than 10% is obtained.

L-L Interaction and ll6He

An OBE potential model for the ^{1}S_0 S = -2 interaction is analyzed with emphasis on the role of coupling between the Lambda Lambda, N Xi, and Sigma Sigma channels. Singlet scalar exchange, an approximation to two-pion exchange, is significant in all channels; surprisingly, the one-pion exchange component is almost negligible. The size of the channel coupling as a function of the overall strength of the OBE model potential is examined. Implications of the analysis for the binding energy of ^{6}_{Lambda Lambda}He are considered; the new experimental datum may suggest a consistency between the extracted Lambda Lambda matrix element and the relation implied by SU(3) among OBE baryon-baryon interactions. \\An OBE potential model for the ^{1}S_0 S = -2 interaction is analyzed with emphasis on the role of coupling between the Lambda Lambda, N Xi, and Sigma Sigma channels. Singlet scalar exchange, an approximation to two-pion exchange, is significant in all channels; surprisingly, the one-pion exchange component is almost negligible. The size of the channel coupling as a function of the overall strength of the OBE model potential is examined. Implications of the analysis for the binding energy of ^{6}_{Lambda Lambda}He are considered; the new experimental datum may suggest a consistency between the extracted Lambda Lambda matrix element and the relation implied by SU(3) among OBE baryon-baryon interactions. \\

ΛΛ6He as a ΛΛ interaction constraint

Abstract The Nijmegen OBE potential D is SU(3) rotated to model the strangeness −2 sector of the baryon-baryon force. Soft core repulsion is introduced to regularize the singular nature of the OBE functions. The strength of the 1S0 t = 0 interaction is adjusted to model three scenarios: (1) a bound state, (2) a narrow virtual, or antibound, state, and (3) an unbound state in which the force is weakly attractive. Using a separable approximation to these potentials, the binding energy of ΛΛ6He is calculated in an ΛΛα model. The resultant binding energies suggest that the strength of the 1S0 t = 0 ΛΛ and the nn interactions should be similar, if the coupling between the ΛΛ and ΞN channels is taken into consideration.The Nijmegen OBE potential D is SU(3) rotated to model the strangeness -2 sector of the baryon-baryon force. Soft core repulsion is introduced to regularize the singular nature of the OBE functions. The strength of the

Electromagnetic disintegration of the A = 3 and A = 4 nuclei

^1

Exact four-body calculation of the 4ΛHe-4ΛH binding energy difference

S

The trinucleons: Physical observables and model properties

_0

Few-body strange systems

t=0

Scattering length measurements from radiative pion capture and neutron-deuteron breakup

interaction is adjusted to model three scenarios: (1) a bound state, (2) a narrow virtual, or antibound, state, and (3) an unbound state in which the force is weakly attractive. Using a separable approximation to these potentials, the binding energy of

Electromagnetic and weak interactions in few-nucleon systems

^{6}_{\Lambda\Lambda}