The Reid93 Potential Triton in the Unitary Pole Approximation

The Reid93 potential provides a representation of the nucleon–nucleon (NN) scattering data that rivals that of a partial wave analysis. We present here a unitary pole approximation (UPA) for this contemporary NN potential that provides a rank one separable potential for which the wave function of the deuteron (³S₁-³D₁) and singlet anti-bound (¹S₀) state are exactly those of the original potential. Our motivation is to use this UPA potential to investigate the sensitivity of the electric dipole moment for the deuteron and ³H and ³He to the ground state nuclear wave function. We compare the Reid93 results with those for the original Reid (Reid68) potential to illustrate the accuracy of the bound state properties.     

On induced double-nucleon emission. III. 12C, (π−, NN) and short-range correlations

The reaction channel (π^?, NN) for the absorption of bound negative pions by nuclei is used as a means to study nuclear short range correlations. A three-body partial-wave analysis has been carried out for the final-state scattering which includes a Reid soft-core nucleon-nucleon interaction and an optical potential. This coupled-channel formalism rapidly converges as we eliminate the asymptotic single-nucleon and deuteron interactions. It is found that for ¹²C reasonable agreement with experiment cannot be obtained in this model without modification of the high relative-momentum components of bound shell model pair wave functions.     

Three-Dimensional Low-Momentum Interaction in Two-Body Bound State Calculations

The deuteron binding energy and wave function are calculated by using the recently developed three-dimensional form of low-momentum nucleon–nucleon (NN) interaction. The homogeneous Lippmann–Schwinger equation is solved in momentum space by using the low-momentum two-body interaction, which is constructed from Malfliet–Tjon potential. The results for both, deuteron binding energy and wave function, obtained with low-momentum interaction, are compared with the corresponding results obtained with bare potential.     

Simple local NN potentials involving forbidden states and polarization in ed scattering

A simple NN potential is proposed in an analytic form. The parameters of this potential are fixed by fitting the effective range, the scattering length, and the deuteron binding energy. The phase shifts for np scattering at energies ranging up to 500 MeV and the properties of the deuteron are calculated with the resulting parameters. The effect of the πNN coupling constant on the potential parameters and on the accuracy in describing various properties of NN interaction is explored. The results of the present calculations are found to be in good agreement with experimental data, with available results from NN partial-wave analyses, and with the results of calculations with Nijmegen potentials. The tensor polarization t ₂₀ in elastic electron-deuteron scattering is analyzed by using some NN interactions.     

Accurate nucleon–nucleon potential based upon chiral perturbation theory

We present an accurate nucleon–nucleon (NN) potential based upon chiral effective Lagrangians. The model includes one- and two-pion exchange contributions up to chiral order three. We show that a quantitative fit of the NN D-wave phase shifts requires contact terms (which represent the short range force) of order four. Within this framework, the NN phase shifts below 300 MeV lab. energy and the properties of the deuteron are reproduced with high-precision. This chiral NN potential represents a reliable starting point for testing the chiral effective field theory approach in exact few-nucleon and microscopic nuclear many-body calculations. An important implication of the present work is that the chiral 2π exchange at order four is of crucial interest for future chiral NN potential development.     

Phase-equivalent transformation which does not affect bound state properties and its manifestation in many-body systems

We propose a phase-equivalent transformation of NN interaction of a new type, the DET-PET transformation, which does not affect the wave function of the bound system (deuteron). The DET-PET properties and its manifestation in many-body systems are studied. In particular, we investigate the correlation of the ³H and ⁴He binding energies (the Tjon line) in calculations with NN potentials obtained by means of DET-PET from the JISP16 NN interaction.     

Baryon resonance components in the deuteron

A non-relativistic coupled channel calculation of the structure of the deuteron is presented with NN¹ configurations in addition to the usual (NN) S- and D-state components. The additional baryon resonance degrees of freedom are included by means of a one-pion exchange potential model; the nucleon-nucleon interactions are treated with conventional phenomenological potentials which contain a hard core. This core obviates the necessity for additional cutoff parameters for the singular NN¹ potentials. All possible NN¹ states of the ten currently “well-established” N¹ resonances have been calculated using a renormalized Reid hard core potential and several NN¹ amplitudes are found in the 0.1–0.3% range. Some of these components are rather large at high momenta and thus may be observable in high momentum transfer processes.     

Contributions of γd → πNN + π0 d channels to the spin asymmetry and the Gerasimov-Drell-Hearn integral for the deuteron

Contributions from the semi-exclusive channels γd → π^± NN + π⁰ d and γd → π⁰ X (X=pn or d) to the deuteron spin asymmetry and the Gerasimov-Drell-Hearn (GDH) integral are explicitly evaluated using an enhanced elementary pion photoproduction operator and a realistic, high-precision potential model for the deuteron wave function. The sensitivity of the results to the elementary pion photoproduction operator is also investigated and considerable dependence is found. Results for the deuteron GDH integral are compared with the measurements from A2 and GDH@MAMI Collaborations.     

The pd → tπ+ reaction in an isobar model: Angular distributions

Various wave function effects are studied in the differential cross section for the pd → tπ⁺ reaction. These include both S- and D-waves for the deuteron and the triton as well as the production of p-wave and d-wave pions. For the triton a parametrized Faddeev wave function is employed and for the deuteron a wave function of Hulthén or McGee type. The two-body correlations considered are NΔ(⁵S₂, ^5D₂, ⁵P₃) and NN(¹D₂) which are found to be the most important partial waves in the pp → dπ⁺ reaction.     

Microscopic description of diffractive deuteron breakup by <Superscript>3</Superscript>He nuclei

A microscopic formalism for describing observed cross sections for deuteron breakup by threenucleon nuclei was developed on the basis of the diffraction nuclear model. A general formula that describes the amplitude for the reaction ²H(³He, ³Hep)n and which involves only one adjustable parameter was obtained by using expansions of the integrands involved in terms of a Gaussian basis. This formula was used to analyze experimental data on the exclusive cross sections for deuteron breakup by ³He nuclei at the projectile energy of 89.4MeV. The importance of employing, in calculations, a deuteron wave function that has a correct asymptotic behavior at large nucleon–nucleon distances was demonstrated.     

3H at Next-to-Next-to-Next-to Leading Order of the Chiral Expansion

The chiral three-nucleon force (3NF) at next-to-next-to-next-to leading order (N³LO) is used to calculate the triton wave function and the doublet nucleon–deuteron scattering length. This allows us to fix the values of the low-energy constants which are free parameters of the theory. The obtained values of these parameters, the expectation values of the kinetic energy, two- and three-body potentials and individual contributions of different parts of 3NF are given.     

Binding energy of triton and scattering lengths in neutron-deuteron collision in Faddeev formalism with local potential

A separable representation for the off-shell two-body t-matrix for a local Hulthén potential is presented, in which deuteron states are chosen as the expansion bases. Using the Faddeev equations with these t-matrices as input, the ground state energy of the triton and doublet and quartet scattering lengths in neutron-deuteron scattering, have been computed. The results have been compared with the experimental findings and the theoretical results of Sitenko et al. obtained in the Sturmian function representation with the same Hulthén potential.     

Probing the origin of the EMC effect via tagged structure functions of the deuteron

We demonstrate that measurement of tagged structure functions of the deuteron in (e, e′N) semi-inclusive reactions can discriminate between different hypotheses on the origin of the nuclear EMC effect. By choosing extreme backward kinematics for the spectator nucleon to minimize effects from the deuteron wave function and final state interactions, one can isolate the modifications in the structure of the bound nucleon within the impulse approximation. The same reaction can be used to extract the large-x neutron to proton structure function ratio.     

Nuclear vertex constants and asymptotic normalization coefficients for the tritium nucleus

The properties of the nuclear vertex constant for virtual triton decay to a deuteron and a neutron (T → d + n) are investigated along with the properties of the asymptotic normalization coefficient defined for the triton wave function and related to this constant. These quantities are calculated numerically on the basis of an equation that relates the asymptotic normalization coefficient to the triton effective radius ρ _T, which was introduced in the present study. The values of G _T² = 1.244(68) fm and C _T² = 2.958(162) found from our calculations are in good agreement with experimental and theoretical estimates obtained for these quantities in other studies. Physical properties of the triton virtual state are also discussed.     

The determination of the D-state asymptotic normalization of the deuteron and triton wavefunctions by the continuation of the 2H(b, p)3H tensor polarizations

By continuation of 14 tensor polarizations to the stripping and pick-up poles of the ²H($\text{d}$,p)³H reaction we have determined ?_D values for the deuteron and triton wavefunctions. The new precision value for the deuteron 0.0272 ± 0.004 suggests an increase of the applied strength of the OPE potentials. For the triton a value of 0.051±0.005 was found.     

Folding model analysis of the nucleus–nucleus scattering based on Jacobi coordinates

This paper presents the results of scattering of ¹⁶O+²⁰⁹Bi interaction near the Coulomb barrier. The interaction potential between two nuclei is calculated using the double folding model with the effective nucleon–nucleon (NN) interaction. The calculations of the exchange part of the interaction were assumed to be of finite-range and the density dependence of the NN interaction is accounted for. Also the results are compared with the zero-range approximation. All these calculations are done using the wave functions of the two colliding nuclei in place of their density distributions. The wave functions are obtained by the D-dimensional wave equation using the hyperspherical calculations on the basis of Jacobi coordinates. The numerical results for the interaction potential and the differential scattering are in good agreement with the previous works.     

The deuteron wave function at short range and the triton

It is shown that if one assumes something between zero and the prediction of the scaling model with dipole fit for the neutron electric form factor, then a variety of short-range behaviour for the deuteron wave function is consistent with existing experimental data on the deuteron electric form factor. This still relatively wide latitude for the inner deuteron wave function, consistent with existing experimental electromagnetic data, gives rise to an off-shell variation of approximately 1.2 MeV in the triton binding energy with a fixed ¹S₀ interaction and a P_D varying from 4.5 to 6.5 %. Interactions with greater densities of matter at short range bind the triton more strongly and closer to the experimental value. An off-shell variation of 0.7 MeV is obtained with a fixed p_d and singlet interaction. However, a single measurement of the deuteron tensor polarization at about q² = 20 fm^?2 would severely restrict this variation.     

OBEP and eikonal form factor: (II). Nuclear matter results

Nuclear matter properties are calculated in a first-order Brueckner-Bethe calculation using a one-boson exchange potential recently proposed by the authors, in which the phenomenological cutoff of dipole type used so far has been replaced by a form factor obtained from an eikonal approximation to multiple vector meson exchange processes. We find ?23.5 MeV saturation energy at a Fermi momentum k_F = 1.77 fm^?1, i.e. about 12 MeV more binding than realistic OBEP using dipole-type cutoffs and about 8 MeV overbinding compared to the empirical value of 16 MeV. On the other hand, estimates suggest that, compared to the Reid soft-core potential, this new OBEP predicts about 1.5 MeV more binding in the case of the triton and about 4 MeV more binding in the case of ¹⁶O, i.e. gives nearly the correct empirical result. The additional binding is traced back to the small deuteron D-state probability of 4.32% predicted by this OBEP, which is a consequence of the special structure of the eikonal form factor. However, taking the effect of the Δ-resonance into account recently given by Green and Niskanen, one arrives at ?14 MeV saturation energy for nuclear matter at k_F = 1.36 fm^?1, whereas the results for the triton and ¹⁶O are changed to a negligible extent only.