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This work deals with investigation of the helicity dependence of the γ → d → → π N N reaction channels near threshold and its implication to the helicity E-asymmetry and the Gerasimov-Drell-Hearn sum rule. Our formalism based on the one loop corrections to the impulse approximation due to nucleon and pion rescattering, uses the realistic Paris NN potential model for the deuteron wave function and the unitary isobar MAID-2007 model for the elementary γN → πN amplitude. We present results for the doubly polarized differential and total cross sections for parallel and antiparallel helicity states, the deuteron spin asymmetry, the helicity E-asymmetry, and the deuteron GDH integral in the near-threshold region. The influence of NN and πN final-state rescattering on the estimated results has been discussed. It is shown that the inclusion of NN rescattering is important, and its inclusion strongly affected the estimated results in both π ± - and π0-production channels. The inclusion of πN rescattering is found to be insignificant in π ± -production, but it has a non- negligible contribution in the case of π0-production. A comparison with predictions of other theoretical models is given.

We investigate coherent π0-photoproduction on the deuteron near threshold with special emphasis on beam-target double spin asymmetries. We present results for the spin asymmetries $T^{c}_{1M}$ (M = 0, 1) for circular polarized photons and vector polarized deuterons, $T^{c}_{2M}$ (M = 1, 2) for circular polarized photons and tensor polarized deuterons, $T^{l}_{1M}$ (M = 0, ± 1) for longitudinal polarized photons and vector polarized deuterons, and $T^{l}_{2M}$ (M = 0, ± 1, ± 2) for longitudinal polarized photons and tensor polarized deuterons in the γd → π0d reaction near threshold. We also discuss the sensitivity of the estimated results to the D-wave component of the deuteron wave function. The unitary isobar MAID-2007 model is used for the elementary γN → πN amplitude. This model is parameterized in terms of invariant amplitudes and allows one to give a more reliable description of the threshold region. The realistic and high-precision Bonn NN potential (full model) is used for the deuteron wave function. We have found that the D-wave component of the deuteron wave function has a little effect on the $T^{c}_{1M}$ (M = 0, 1) and $T^{l}_{2M}$ (M = 0, 1, 2) spin asymmetries. On the contrary, we have obtained a significant role of the D-wave component on the spin asymmetries $T^{c}_{2M}$ (M = 1, 2), $T^{l}_{1M}$ (M = 0, ± 1), and $T^{l}_{2M}$ (M = − 1,− 2).

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.

Near-threshold coherent photoproduction of π0-meson on the deuteron is investigated. Numerical results for the unpolarized differential and total cross sections, the linear photon Σ-asymmetry, the vector T11 and tensor T2M (M = 0, 1, 2) deuteron spin asymmetries, and the spin asymmetry $$\tilde{T}_{20}$$ of the total cross section are presented. The role of D-wave component of the deuteron wave function on these physical observables is studied. The calculations are based on the impulse approximation in which we use the realistic and high-precision Bonn NN potential (full model) for the deuteron wave function and the unitary isobar MAID-2007 model for the elementary γN → πN amplitude that describes well the threshold region. We have found that the D-wave component has a negligible effect on the unpolarized cross sections and the vector deuteron T11-asymmetry at photon lab-energies close to threshold. On the contrary, we have obtained a significant role of the D-wave part of the deuteron wave function on the Σ, T2M, and $$\tilde{T}_{20}$$ spin asymmetries. The results for the unpolarized differential cross section are compared to the experimental data from TAPS and a satisfactory agreement within the uncertainties has been obtained at forward pion angles. At backward pion angles, our results underestimate the experimental data and a disagreement has been found.

Polarized response functions for beam and target polarization in the elastic electron-deuteron scattering process are investigated. We report numerical results for all the non-vanishing polarized response functions as functions of the four-momentum transfer square Q2. The sensitivity of the predicted results to the nucleon form factors is investigated. For the neutron and proton form factors, the standard dipole fit, the modified dipole fit 1, the modified dipole fit 2, and the relativistic harmonic oscillator model are used. In addition, the dependence of the results on the deuteron wave functions obtained from different modern N N potentials is studied. For this purpose, the realistic and high-precision Argonne υ18, chiral N3LO, Nijmegen-I, and CD-Bonn N N potentials are used. We found that all the non-vanishing polarized response functions are sensitive to the choices of nucleon form factors, whereas they are slightly dependent on the N N potential model adopted for the deuteron wave function. The results for all polarized response functions using the relativistic harmonic oscillator model for the nucleon form factors are found to be very small in comparison to the results of other models.

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.

We present the first accurate results of measurements of the tensor analyzing power component $$T_{20}$$ for the coherent neutral pion photoproduction on the deuteron. The measurements were performed at the Budker Institute of Nuclear Physics at VEPP-3 storage ring using the internal tensor polarized deuterium target. The measurements cover the region of photon energy from 200 to 450 MeV and the region of the center-of-mass pion polar angle from 100 to 140 degrees. The results obtained are compared with predictions of several theoretical models.

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.

This paper presents new results for the [Formula: see text]-component of the tensor analyzing power of the reaction [Formula: see text] in the photon energy range of [Formula: see text]. The experimental statistics accumulated in 2013 at the VEPP-3 accelerator-storage complex is used. The reaction events are identified by the coincidence registration of the proton and two [Formula: see text]-quanta from the decay of the neutral pion. To determine the [Formula: see text]-component, the asymmetry of the yields with respect to the change of sign of the tensor polarization of the deuterium target is measured. The experimental results are compared with the theoretical calculations in which the MAID 2007 model is used as the elementary pion–nucleon photoproduction amplitude and contributions from the pion–nucleon and nucleon–nucleon rescattering are taken into account.

Single and double spin asymmetries in the elastic electron-deuteron (e-d ) scattering were investigated. The tensor-deuteron asymmetries T2i(i = 0, 1, 2) and the beam-vector-deuteron asymmetries T e 1i(i = 0, 1) were calculated and compared with the available experimental data. The sensitivity of the results for these spin asymmetries to the deuteron wave function has been investigated. The predicted asymmetries were found to be agree with one another and with experiment. It was found that, the double spin asymmetry T e 10 is much smaller than the T e 11-asymmetry. Therefore, in addition to the single tensor-deuteron asymmetry T20, the doubly beam-vector-deuteron asymmetry T e 11 can be used as an another tool for extracting the deuteron electromagnetic form factors.

The photoproduction of $\pi^0$-mesons from the nucleon and deuteron has been studied for incidents of photon energies up to 1.5 GeV. By using the MAID-2007 model for the process on the nucleon, we predict results for the unpolarized and helicity-dependent total cross sections of the semi-exclusive reaction $\gamma d\rightarrow\pi^0X$ ($X=np+d$) with the inclusion of rescattering effects. We find that rescattering effects yield a substantially large contribution. The extracted results are compared with the available experimental data and a satisfactory agreement is obtained. In addition, the contribution of $\gamma d\rightarrow\pi^0X$ ($X=np+d$) to the finite GDH integral has been evaluated by explicit integration up to 1.5 GeV and a total value of 256.96 $\mu$b has been obtained. Convergence of the GDH integral has been reached., Comment: Mini Review, 6 Pages, 6 Figures, 1 Table

Near-threshold incoherent pion photoproduction on the deuteron including final-state rescattering effects is investigated with special emphasize on the beam-target double spin asymmetries. The elementary γ N → π N amplitude is taken from the unitary isobar MAID-2007 model which describes well the threshold region. We present the first results on all possible double spin asymmetries of the differential and total cross sections for both the charged- and neutral-pion production channels near threshold. We discuss the sensitivity of the estimated results to the N N and π N final-state rescattering effects. It turns out that the role of N N -rescattering is significant, and its inclusion strongly affected the results for double spin asymmetries in the charged- and neutral-pion channels. We also find that the π N -rescattering effect is insignificant in the case of charged-pion channels, whereas it has a noticeable contribution on most of double spin asymmetries in the neutral-pion channel.

The influence of intermediate η N N interaction on spin asymmetries for coherent π 0 -photoproduction on the deuteron in the energy region around the η -threshold is studied using a three-body model with separable two-body interactions. We calculate all possible spin asymmetries with polarized photons and/or oriented deuterons and compare our results with available data. The calculations are based on a theoretical approach which includes the amplitudes of the impulse approximation, two-body process with π N - and η N -rescattering, and the higher order terms in the multiple scattering series for the intermediate η N N interaction. We found that the results for spin asymmetries of the differential cross section differ significantly from those calculated by a simple model in which only the impulse approximation and first-order rescattering contributions are considered. The effect of intermediate η N N interaction is significant in certain spin asymmetries, specially at extreme backward pion angles. It turns out that the inclusion of a full η N N three-body contribution is quite essential. The spin asymmetries of the total cross section are much less affected by rescattering contributions. Compared to the experimental data from YerPhi Collaboration for the linear photon asymmetry, sizeable discrepancies are found.

Coherent photoproduction of π0-meson from the deuteron near π0-production threshold is investigated with special emphasize on single polarization observables. We report numerical results for the linear photon asymmetry Σ and tensor deuteron spin asymmetries T2M (M=0,1,2). The sensitivity of obtained results to the D-state contribution in the deuteron wave function of realistic NN potentials is studied. It is shown that the influence of D-state contribution on the predicted spin observables is sizable, and it provides important constraints for the extraction of the elementary neutron amplitude. Compared with the experimental data from TAPS collaboration for differential cross section, we obtain a satisfactory agreement.Coherent photoproduction of π0-meson from the deuteron near π0-production threshold is investigated with special emphasize on single polarization observables. We report numerical results for the linear photon asymmetry Σ and tensor deuteron spin asymmetries T2M (M=0,1,2). The sensitivity of obtained results to the D-state contribution in the deuteron wave function of realistic NN potentials is studied. It is shown that the influence of D-state contribution on the predicted spin observables is sizable, and it provides important constraints for the extraction of the elementary neutron amplitude. Compared with the experimental data from TAPS collaboration for differential cross section, we obtain a satisfactory agreement.

Coherent π 0 -photoproduction on the deuteron including polarization observables is studied in the energy region near the η -production threshold at backward center-of-mass angles of the outgoing pion. This work is motivated by the measurements of the CLAS Collaboration at Jefferson Lab, where a cusp-like structure in the energy dependence of the differential cross section has been observed at extremely backward pion angles. The present approach is based on the impulse approximation and first-order rescattering diagrams with intermediate production of both π - and η -mesons. Numerical results for unpolarized cross sections, the linear photon asymmetry ( Σ ), the vector ( T 11 ) and tensor ( T 2 M , M = 0 , 1, 2) deuteron target asymmetries, and the double polarization E -asymmetry are predicted and compared with available experimental data and other theoretical models. The effect of first-order rescattering is found to be much larger in spin asymmetries than in the unpolarized cross sections. It reaches on average about 40% in the tensor target and E asymmetries. Compared to the experimental data from CLAS Collaboration, sizable discrepancies are found. This is not the case for the linear photon asymmetry, for which a better comparison with the data from YerPhI Collaboration is obtained.

Incoherent pion photoproduction on the deuteron γ d → π N N is investigated in the energy region E γ thr ≤ E γ ≤ 160 MeV. The model applied contains the amplitudes of the impulse approximation as well as the N N and π N rescattering in the final state. For the elementary γ N → π N amplitude, the unitary isobar MAID-2007 model is used. This model is parameterized in terms of invariant amplitudes and allows one to give a more reliable description of the threshold region. The half-off-shell N N and π N scattering amplitudes are obtained from separable representations of realistic N N and π N interactions, respectively. For the first time, numerical results for the linear photon asymmetry Σ , vector T 11 and tensor T 2 M ( M = 0 , 1 , 2 ) deuteron spin asymmetries for the reactions γ d → π − p p , γ d → π + n n , and γ d → π 0 n p are presented. In addition, results for the unpolarized differential and total cross sections are given. We found that the influence of N N rescattering is moderate in both charged-and neutral-pion production channels, whereas π N rescattering is almost negligible in the charged-pion production channels which is not the case in neutral-pion production since a noticeable contribution is obtained. The calculated results for unpolarized differential and total cross sections are compared with the available experimental data and other theoretical models, and a satisfactory agreement is obtained.

Quasifree pion photoproduction from the deuteron including polarization observables is studied in the energy region from threshold up to the Δ(1232)-resonance with inclusion of all leading πNN effects. For the elementary pion photoproduction operator, a realistic effective Lagrangian approach is used which displays chiral symmetry, gauge invariance, and crossing symmetry, as well as a consistent treatment of the spin-3/2 interaction. The interactions in the final two-body subsystems are taken in separable form. The sensitivity of the results to the elementary N(γ,π)N operator is investigated. A considerable dependence on the elementary amplitude of the target asymmetry for the d(γ,π)NN case is found. This indicates that this observable can serve to test different choices of elementary operators.

The separated structure functions R L , R T , R LT , and R TT governing the semi-exclusive differential cross section for the d ( e , e ′ π ) NN reaction are evaluated in the energy region from threshold up to 500 MeV. We present results for both the neutral and the charged pion production channels in a variety of kinematic settings. For the elementary pion electroproduction operator, the realistic unitary isobar MAID-2003 model is used which gives a good description of the process on the free nucleon. The completely inclusive form factors, which determine the inclusive differential cross section when only the scattered electron is detected, are also computed. It has been found that the structure functions and form factors reveal clear differences between the production dynamics for the π 0 and π ± pions. Considerable dependencies of the structure functions and form factors on the pion angle and virtual photon lab-energy are found. The predicted results are found to be insensitive to the potential model used for the deuteron wave function.

Based on a prior effective Lagrangian model on single pion photoproduction from the nucleon, successfully tested in total and differential cross-sections, we study theoretically the helicity dependence from the interaction of circularly polarized photons and a longitudinally polarized nucleon target in the energy range from π-threshold through the Δ(1232)-resonance region. The doubly polarized total and differential cross-section differences for parallel and antiparallel helicity states are predicted and compared with the experiment. We show that the results are sensitive to interferences among different contributions to the process and, thus, represent a complementary test of the theoretical model. A quite satisfactory agreement with recent experimental data from the GDH-collaboration is obtained.

The role of the final-state NN -rescattering ( NN -FSI) in the polarization observables of the inclusive reaction d ( γ , π − ) p p , involving polarization of the photon beam and/or the deuteron target, is investigated. Various single- and double-spin asymmetries are studied with respect to the influence of such interaction effect and numerical predictions are given for forthcoming experiments. It has been found that the effect of NN -FSI is quite important for the single-spin asymmetries Σ , T 20 , T 21 and T 22 and the double-spin asymmetry T 20 l , whereas it is much less important for the vector target asymmetry T 11 and other beam-target double-polarization asymmetries. Furthermore, we found that the inclusion of the NN -FSI improves the description of the LEGS data for the linear photon asymmetry.

The influence of final-state NN-rescattering on the beam asymmetry Σ for linearly polarized photons in π − photoproduction on the deuteron in the energy range from π-threshold through the Δ ( 1232 ) -resonance has been investigated. Numerical results for this spin observable are predicted and compared with recent experimental data from the LEGS Spin Collaboration. Final-state NN-rescattering is found to be quite important and leads to a better agreement with existing experimental data. Furthermore, the differences with other theoretical models have been discussed.

Polarization observables of the three charge states of the pion for the γd→π NN reaction with polarized photon beam and/or oriented deuteron target are evaluated over the whole Δ(1232)-resonance region adopting a nonrelativistic model based on time-ordered perturbation theory. Results for the π-meson spectra, linear photon asymmetry, vector and tensor target asymmetries are presented. Particular attention is given, for the first time, to double polarization asymmetries for which we present results for [Formula: see text] and [Formula: see text]. We find that all other double polarization asymmetries of photon and deuteron targets vanish.

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.

We propose a new approximation scheme to obtain analytic expressions for the Schrodinger equation with isotropic velocity-dependent potential to determine the scattering phase shift. In order to test the validity of our approach, we applied it to an exactly solvable model for nucleon-nucleon scattering. The results of the variation iteration method (VIM) formalism compare quite well with those of the exactly solvable model. The developed formalism can be applied in problems concerning pion-nucleon, nucleon-nucleon, and electron-atom scattering.

Influence of the choice of the NN potential model governing the deuteron wave function on the observables for coherent π0-photoproduction on the deuteron near η-threshold is investigated by using a three-body model for the intermediate ηNN system with separable two-body interactions. Results for unpolarized differential cross section and polarization observables are predicted. It is revealed that the choice of the NN potential model has a visible effect on the differential cross section and most of the polarization observables, especially in the photon energy range of 600–800 MeV and extreme backward pion angles. We find that the deviation among results obtained by using different deuteron wave functions is quite large. The use of the CD-Bonn NN potential for deuteron wave function doubles the differential cross section in this kinematic region. Compared with the experimental data from CLAS collaboration for differential cross section, sizeable discrepancies are found.

Quasifree single‐pion photoproduction on the deuteron via the exclusive reaction d(γ, π0n)p is studied in the Δ(1232)‐resonance region including all leading πNN effects. Special emphasizes are given to single spin observables. The elementary pion photoproduction amplitude from free nucleons is taken from the dynamical model of Sato and Lee (SL model) [Phys. Rev. C54 (1996) 2660]. The interactions in the final two‐body subsystems are taken in separable form. Final‐state interaction effects are found to be significant and lead to an improved agreement with the most recent experimental data from Brookhaven National Laboratory (LEGS‐exp.L3b).

The helicity dependence of the inclusive $\pi^-$ photoproduction reaction from the deuteron in the $\Delta$(1232)-resonance region is investigated with inclusion of final-state nucleon-nucleon rescattering ($NN$-FSI). For the elementary $\pi$-production operator an effective Lagrangian model which includes the standard pseudovector Born terms and a contribution from the $\Delta$-resonance is used. The half-off-shell $NN$-scattering matrix is obtained from a separable representation of a realistic $NN$-interaction. The differential polarized cross-section difference for parallel and antiparallel helicity states is predicted and compared with experiment. We find that the effect of $NN$-FSI is much less important in the helicity difference than in the previously studied unpolarized differential cross section. Furthermore, the contribution of $\vec d(\vec\gamma,\pi^-)pp$ to the deuteron spin asymmetry is explicitly evaluated with inclusion of $NN$-FSI. It has been found that the effect of $NN$-FSI is much larger in the asymmetry than in the total cross section, and this leads to an appreciable reduction of the spin asymmetry in the $\Delta$-region. Inclusion of such effect also leads to improved and quite satisfactory agreement with existing experimental data., Comment: 13 pages, 6 eps figures, published in Prog. Theor. Phys. 113 (2005) 169-181

Spin observables for the three charge states of the pion for the pion photoproduction reaction on the deuteron, $\gamma d\to\pi NN$, with polarized photon beam and/or oriented deuteron target are predicted. For the beam-target double-spin asymmetries, it is found that only the longitudinal asymmetries $T_{20}^{\ell}$ and $T_{2\pm 2}^{\ell}$ do not vanish, whereas all the circular and the other longitudinal asymmetries do vanish. The sensitivity of spin observables to the model deuteron wave function is investigated. It has been found that only $T_{21}$ and $T_{22}$ are sensitive to the model deuteron wave function, in particular in the case of $\pi^0$-production above the $\Delta$-region, and that other asymmetries are not., Comment: 16 pages, 8 figures, accepted for publication in J. Phys. G: Nucl. Part. Phys

Incoherent photoproduction of pions on the deuteron in the first resonance region is investigated with special emphasis on single-spin asymmetries. For the elementary pion production operator an effective Lagrangian model which includes the standard pseudovector Born terms and a resonance contribution from the $\Delta$(1232)-excitation is used. Single-spin asymmetries, both for charged and neutral pion photoproduction on the deuteron, are analyzed and calculated for the first time in the first resonance region. The linear photon asymmetry $\Sigma$, vector target asymmetry $T_{11}$ and tensor target asymmetries $T_{20}$, $T_{21}$, and $T_{22}$ for the reaction $d(\gamma,\pi)NN$ are predicted for forthcoming experiments., Comment: 20 pages including 5 postscript figures, minor revisions in the text added, no changes in the results and in the conclusions

The contribution of incoherent single pion photoproduction to the spin response of the deuteron, i.e., the asymmetry of the total photoabsorption cross section with respect to parallel and antiparallel spins of photon and deuteron, is calculated over the region of the $\Delta$-resonance with inclusion of final state $NN$- and $\pi N$-rescattering. Sizeable effects, mainly from $NN$-rescattering, are found leading to an appreciable reduction of the spin asymmetry. Furthermore, the contribution to the Gerasimov-Drell-Hearn integral is explicitly evaluated by integration up to a photon energy of 550 MeV. Final state interaction reduces the value of the integral to about half of the value obtained for the pure impulse approximation., Comment: 4 pages EPJ style including 4 postscript figures

In the present work [1] incoherent photoproduction of pions on the deuteron in the Δ(1232) resonance region is investigated where besides the impulse approximation (IA) complete two-body rescattering in the nucleon-nucleon (NN) and pion-nucleon (πN) final state subsystems is included (see Fig. 1). The elementary γN → πN amplitude including Born and Δ(1232) resonance contributions is taken from previous work of [2].

The influence of final state $NN$- and pi N-rescattering in incoherent pion photoproduction on the deuteron has been investigated. For the elementary photoproduction operator an effective Lagrangian model is used which describes well the elementary reaction. The interactions in the final two-body subsystems are taken in separable form. While NN-rescattering shows quite a significant effect, particularly strong for neutral pion production, pi N-rescattering is almost negligible. Inclusion of such effects leads to an improved and quite satisfactory agreement with experiment., 18 pages revtex4 including 16 postscript figures

The present status of the theoretical description of electromagnetic reactions on the deuteron above pion threshold is reviewed. Three major topics are considered: (i) retardation effects in $\pi$-meson exchange contributions to $NN$-interaction and meson exchange currents in deuteron photodisintegration above $\pi$-threshold in the $\Delta$-resonance region, (ii) off-shell effects in the one-body current treated in a simple pion cloud model in deuteron photodisintegration in and above the $\Delta$-resonance region, and (iii) final state interaction effects in photoproduction of $\pi$ and $\eta$ mesons on the deuteron., Comment: 10 pages latex, invited talk at the Second Asia Pacific Conference on Few-Body Problems in Physics, Proceedings to be published in Modern Physics Letter A

The helicity dependence of the \(\vec{\gamma }\vec{d} \to \pi ^{0}d\) reaction is studied for incident photon lab-energies near the η-threshold at backward center-of-mass pion angles. The influence of first-order rescattering with intermediate production of both π- and η-mesons on the doubly polarized differential and total cross sections for parallel and antiparallel helicity states is investigated. Then the contribution of \(\vec{\gamma }\vec{d} \to \pi ^{0}d\) to the deuteron spin asymmetry of the total cross section is calculated and its contribution to the Gerasimov–Drell–Hearn (GDH) integral for the deuteron is explicitly evaluated by integration up to a photon lab-energy of 900 MeV. Moreover, the double polarization E-asymmetry is predicted. Although the first-order rescattering effect is found to be negligible in the doubly polarized total photo-absorption cross sections and the deuteron GDH integral, it reached on average about 40% in the doubly polarized differential cross sections and the helic...