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The binding energy per nucleon for nuclear matter, i.e., equation of state (EOS), within the Brueckner–Hartree–Fock (BHF) approach with the consideration of various three-body forces (3BFs) like the phenomenological 3BF and by adding a contact term to the BHF calculations are considered at variance densities. The 3BF contribution turns out to be nonnegligible contribution and to have a substantial saturation effect. The calculations are done utilizing the CD-Bonn and Argonne V18 nucleon–nucleon (NN) potentials. These NN potentials give great fitting to the deuteron properties and are phase-shift equivalent. The resultant EOS is compatible with the phenomenological analysis on the saturation point. It is demonstrated that the 3BF influences significantly on the nuclear matter EOS at high densities. Moreover, it is necessary for reproducing the empirical saturation properties for symmetric nuclear matter. The pressure has been also calculated and the suggested approaches reproduce fairly well agreement with the empirical data. We also examined the maximum neutron star masses which are close to two solar masses, which is again compatible with recent observational data. Comparison with other microscopic EOS is presented and discussed.

The spin response of the $$\vec{\gamma}\vec{d}\to\pi^{0}d$$ reaction near threshold is investigated. Our formalism based on the impulse approximation, uses the realistic Bonn $$NN$$ potential (full model) for the deuteron wave function and the unitary isobar MAID-2007 model for the elementary $$\gamma N\to\pi N$$ amplitude. We present the first results for the double polarized differential and total cross sections for parallel and antiparallel helicity states, the deuteron spin asymmetry, the helicity $$E$$ -asymmetry, the deuteron GDH integral, and the double spin asymmetries of the total cross section in the near-threshold region. Sensitivity of the estimated results to the $$D$$ -wave effect of the deuteron wave function for a realistic $$NN$$ potential is studied. We find an insignificant sensitivity of most of the estimated observables to the $$D$$ -wave component. A noticeable role is obtained only in the double polarized differential cross section with antiparallel spins of photon and deuteron $$d\sigma^{A}/d\Omega_{\pi}$$ close to the threshold energy at forward and backward pion angles as well as in the double spin asymmetry of the total cross section $$\sigma\tilde{T}_{20}$$ at relatively large photon energies. Thus, we compare results for these two observables using various $$NN$$ potential models with different $$D$$ -state probabilities, and a noticeable influence is found.

Influence of nucleon structure on single tensor-deuteron and double beam-vector-deuteron analyzing powers in the elastic electron-deuteron scattering process is investigated. We report numerical results for the tensor-deuteron (T20, T21, and T22), and beam-vector-deuteron (T10 and T11) analyzing powers as functions of the four-momentum transfer square Q2 and the electron scattering angle in the laboratory frame θe. This is made possible with the advent of recent polarization measurements with polarized electron beams and/or polarized deuteron targets at MIT-Bates, JLab, NIKHEF, VEPP-2, and VEPP-3. We found that the predicted results for T21, T22, T10, and T11 are sensitive to the nucleon electromagnetic form factors. On the contrary, the T20 analyzing power is found to be almost independent on the actual nucleon form factors. The predicted analyzing powers are compared with the available experimental data and a satisfactory agreement is obtained.

In this study, the sensitivity of tensor-deuteron and beam-vector-deuteron analyzing powers in elastic e-d scattering to modern local and nonlocal NN potentials is investigated. We report numerical results for the tensor-deuteron (T20, T21, T22) and beam-vector-deuteron (T10, T11) analyzing powers as functions of the four-momentum transfer square $$Q^2$$ and the electron scattering angle in the laboratory frame $$\theta _e$$ . This could be made possible with the advent of recent polarization measurements with polarized electron beams and polarized deuteron targets at MIT-Bates, JLab, NIKHEF, VEPP-2, and VEPP-3. We found that the estimated results for T20, T21, and T22 are slightly dependent on the local and nonlocal NN potential models adopted for the deuteron wave functions up to $$Q^2\simeq $$ 0.5 (GeV/c) $$^2$$ . At $$Q^2>$$ 0.5 (GeV/c) $$^2$$ , the theoretical discrepancies among various local and nonlocal NN potential models were found. As for the beam-vector-deuteron analyzing powers T10 and T11, we also found that they started to become model dependent when $$Q^2 > $$ 0.5 (GeV/c) $$^2$$ . The considerable dependence of T10 and T11 on the local and nonlocal NN potential models was observed at extremely forward electron angles. The T10 analyzing power was found to be smaller than T11. Therefore, in addition to the single analyzing power T20, the double beam-vector-deuteron analyzing power T11 can be used as another tool for extracting the three deuteron form factors, which provide an intuitive picture of the internal structure of the deuteron. The predicted results for analyzing powers are also compared with the available experimental data and a satisfactory agreement was obtained.

Motivated by the recent measurements from the VEPP-3 electron storage ring, we investigate the tensor target polarization asymmetries T2M (M = 0, 1, 2) in the reaction γd → π0d with a particular interest in the effect of the intermediate ηNN three-body approach. This approach is based on realistic separable representations of the driving two-body interaction in the πN, ηN, and NN subsystems. It is shown that the influence of rescattering effects in the intermediate state on the tensor target spin asymmetries is sizable at extreme backward pion angles. At forward angles, the contribution from the pure impulse approximation is dominated and the spin asymmetries show very little influence of rescattering effects. The sensitivity of results to the elementary pion photoproduction operator and to the NN potential model adopted for the deuteron wave function is investigated, and considerable dependences are found. The predicted spin asymmetries are also compared with available experimental data, and a satisfactory agreement with the recent data from VEPP-3 is obtained at photon energies below 400 MeV. At higher energies, the calculated spin asymmetries slightly underestimate the data.

The Equation of State (EOS) of pure neutron matter at zero temperature is calculated up to five saturation densities within the Brueckner theory with the inclusion of three-body forces. Three different realistic and accurate two-body forces are considered to evaluate the G-matrix effective interaction for nuclear matter. These models are the chiral N 3 LO, the CD-Bonn and the Argonne V18, which give quite different EOS. Two types of three-body forces are included to the effective interaction, which might be important at densities several times that of nuclear matter density. Using a microscopic EOS for pure neutron matter, static properties of non-rotating neutron stars such as masses and radii are evaluated. The resulting maximum masses of neutron star using different interactions near 2 Mʘ are found to be in reasonable agreement with the measured ones PSR J1614−2230 (with Mmax = 1.97 ± 0.04 Mʘ) and PSR J0348+0432 (with Mmax = 2.01 ± 0.04 Mʘ).

Tensor target spin asymmetries [Formula: see text] ([Formula: see text]=0,1,2) in the reaction [Formula: see text] are studied for photon energies from [Formula: see text]-threshold up to 1.5[Formula: see text]GeV with inclusion of rescattering effects. It is shown that the influence of rescattering effects on the tensor target spin asymmetries is sizable in the energy region near [Formula: see text]-threshold. At higher energies, much smaller influence of rescattering effects is seen. The sensitivity of the obtained results to the elementary pion photoproduction operator is investigated and a considerable dependence is found, in particular at forward pion angles. In addition, a comparison with results of other theoretical models is also given. The extracted spin asymmetries are compared with available experimental data and a qualitative agreement is obtained. The predictions presented here may be useful to interpret the recent measurements from the VEPP-3 electron storage ring.