Polarization effects in inelastic deuteron scattering in the region of baryon-resonance excitation

Within the impulse approximation, polarization effects in inelastic deuteron scattering on nuclei are investigated in the region around the resonance of mass about 2190 MeV/c ². It is shown that the spin-dependent part of the NN → NN*(2190) amplitude plays a significant role at high momentum transfers. Predictions are obtained for some polarization observables and cross sections for various deuteron-spin-flip processes.     

Monte Carlo simulation of elastic and quasielastic nucleus-nucleus scattering

The amplitude of elastic nucleus-nucleus scattering is calculated in framework of the multiple scattering theory. We consider the dependence of the amplitude on slope and cross section ofNN scattering, and on nuclear matter density. The results are compared to approximate calculations. The total inelastic nucleus-nucleus cross sections as well as the cross sections of quasielastic processes are calculated. Predictions are given for the case of superhigh energies.     

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.     

Gluon shadowing and unitarity effects

New data from HERA experiment on deep inelastic scattering have been used to parametrize nucleon and Pomeron structure functions. Within the Gribov theory, the parameterizations were employed to calculate gluon shadowing for various heavy ions. The latter was compared with predictions from other models. Calculations of multiplicity reduction due to gluon shadowing for d+Au collisions at forward rapidities at √s _NN =200 GeV are in good agreement with BRAHMS data on the nuclear modification factor.     

Testing effective nucleon-nucleon forces to describe diagonal spin-transfer coefficients for the scattering of polarized protons with the excitation of the 1+ levels in 12C

The diagonal coefficients of spin-transfer D _ii in the small-angle inelastic scattering of polarized protons with the excitation of the two lowest 1⁺ levels in ¹²C are analyzed. The isoscalar (T = 0, E* = 12.71MeV) and isovector (T = 1, E* = 15.11 MeV) transitions are considered. The coefficients D _ii are calculated within DWBA using different effective nucleon-nucleon (NN) interactions between an incident proton and the nucleons of the nucleus. We consider the Franey-Love interaction and the Geramb effective interactions based on the Paris NN potential, and also the effective NN potential based on the chiral perturbation theory, etc. The impact of the wave function antisymmetrization is studied from the coefficients D _ii in a system that includes a projectile and nucleons of the nucleus, along with the impact of other effects.     

The two-pion exchange NN potential in nuclear matter and nuclear stability

A meson exchange model of the ππ interaction which fits free ππ scattering data is used to calculate the interactions of pions in nuclear matter as a function of nuclear density. Polarization of the nuclear medium by the pions results in a marked increase in the s-wave ππ attraction at low energy. The influence of this effect on the nucleon-nucleon interaction is a corresponding increase with density of the NN central potential due to the exchange of two correlated pions, resulting in an NN interaction which fails to saturate. A possible mechanism for restoring the theoretical stability of nuclear matter is explored and found to be effective.     

Gottfried sum rule and the shape ofF 2 ⌍ -F 2 ⌍

The recent experimental determination of the Gottfried sum rule of deep inelastic scattering provides strong evidence that SU(2) flavor symmetry is broken by the sea quark distributions of the nucleon. Two mechanisms have been suggested to explain the data: Pauli blocking and non-perturbative contributions to the sea arising from the pion cloud surrounding the nucleon. We investigate the effects of these two mechanisms on several standard parametrizations of the quark distribution functions and find that each mechanism has different effects on the shapes of these distribution functions. The best agreement between the experimental data and the modified quark distributions occurs when both mechanisms are taken into account using a softπNN form factor and a small Pauli correction.     

Systematics of low-energy πN scattering

A simple current algebra model is shown to account for a wide range of low-energy πN experimental data including twenty-eight subthreshold expansion coefficients, six scattering lengths, and the scattering phase shifts below T_π = 300 MeV. A sigma term of σ_NN = 62 ± 10 MeV is obtained.     

Exact solution of a model for πd induced reactions and its application to pion-nucleus reactions

Reduction techniques are applied to πd elastic scattering and π-absorption in a theory without anti-nucleons. In a one-pion approximation we derive two sets of exact coupled-channel equations for respectively the amplitudes T_πd,NN, T_{Nδ, NN} and T_{πd, πd}, T_{d, NΔ}- Alternatively we express in terms of the absorption amplitude T_{πd, NN} available solutions for a three-body problem restricted to the πd and NΔ channels. We explicitly demonstrate that our model (which comes close to the one of Thomas, Mizutani and Koltun) strictly respects the Pauli principle and avoids double-counting. Using the same technique we determine amplitudes for the (π, 2N) reaction and for π (in)elastic scattering on general nuclei in terms of amplitudes amongst the NN, NNπ channels. Both the elastic amplitude and the πA optical potential are shown to decompose into a multiple scattering part based on an input πN amplitude without the P₁₁ partial wave and calculable absorption corrections.     

Polarization observables <Emphasis Type="Italic">P</Emphasis> + <Emphasis Type="Italic">A</Emphasis> and (<Emphasis Type="Italic">P</Emphasis> + <Emphasis Type="Italic">A</Emphasis>)σ in 200-MeV proton inelastic scattering

Experimental and calculated data on inelastic scattering of polarized protons are presented as polarization-analyzing-power combinations P + A and (P + A)σ for the 0⁺ → 1⁺, T = 1 transition in ¹²C. Data on the polarization P and the function (P ? A)σ are also reported. Microscopic calculations have been performed using the DWBA program with the G-matrix interaction based on the Paris and Bonn potentials. A significant difference between the effective interaction with density correction and free NN interaction has been demonstrated. It is established that the (P + A)σ combination is especially sensitive to systematic variations in the density dependence in effective NN interactions.     

Nucleon-nucleon interaction: A typical/concise review

Nearly a recent century of work is divided to Nucleon-Nucleon (NN) interaction issue. We review some overall perspectives of NN interaction with a brief discussion about deuteron, general structure and symmetries of NN Lagrangian as well as equations of motion and solutions. Meanwhile, the main NN interaction models, as frameworks to build NN potentials, are reviewed concisely. We try to include and study almost all well-known potentials in a similar way, discuss more on various commonly used plain forms for two-nucleon interaction with an emphasis on the phenomenological and meson-exchange potentials as well as the constituent-quark potentials and new ones based on chiral effective field theory and working in coordinate-space mostly. The potentials are constructed in a way that fit NN scattering data, phase shifts, and are also compared in this way usually. An extra goal of this study is to start comparing various potentials forms in a unified manner. So, we also comment on the advantages and disadvantages of the models and potentials partly with reference to some relevant works and probable future studies.     

Description of resonant states in the shell model

A technique for describing scattering states within the nuclear shell model is proposed. This technique is applied to scattering of nucleons by particles based on ab initio No-Core Shell Model calculations of ⁵He and ⁵Li nuclei with JISP16 NN interaction.     

Nonlocal nucleon-nucleon interaction JISP

The J-matrix inverse scattering formalism is described and a new type of nucleon-nucleon interaction JISP is constructed within its framework. Interaction for each partial NN scattering is represented by a small matrix in the oscillator basis, which allows its direct use in multiparticle shell-model calculations and in calculations within the resonating group approximation. The JISP reproduces np scattering data and deuteron characteristics with an accuracy of modern realistic NN potentials (x ²/datum = 1.05). The generalization of this interaction which takes into account violation of charge independence of nucleon-nucleon forces is proposed and pp scattering phases calculated with this new charge-dependent interaction CD-JISP are discussed.     

Elastic and inelastic scattering of 178 MeV protons from 58Ni and 60Ni

The elastic and inelastic scattering of 178 MeV protons from ⁵⁸Ni and ⁶⁰Ni has been studied. Angular distributions were measured for the differential cross sections for elastic scattering as well as inelastic scattering from excited states below about 5 MeV, all with natural parity. For the elastic and for the inelastic scattering from the first excited state (2⁺ in both nuclei, the angular distributions for the polarization were also measured. The measurements extend out to c.m. angles of about 60°, corresponding to a momentum transfer of about 600 MeV/c.The elastic and inelastic scattering data were compared to the results of coupled-channel calculations in the vibrational model using a deformed spin-orbit interaction of the full Thomas form. Good agreement was found in general showing that the main features of the experimental results are well described in this model.     

The analysis of elastic and inelastic scattering of alpha particles using a folding potential

The elastic and inelastic scattering of alpha particles from Cd and Te isotopes are analysed in terms of a single folding model in which the scattering potential is approximated by folding an effectiveα-nucleon interaction into the mass distribution of the target nuclei. Excellent fits are obtained to the elastic scattering data. However, to obtain equally good fits to inelastic scattering data arbitrary adjustments of the effective interaction are required.     

Elastic and inelastic scattering of 11.8 MEV polarized deuterons from 34S

The elastic and inelastic scattering of 11.8 MeV vector polarized deuterons from ³⁴S has been studied. Angular distributions of the cross section σ(θ) and vector analyzing power iT₁₁(θ) have been measured for the ground state and the first three excited states in ³⁴S. Optical model parameters were first obtained by fitting the elastic deuteron scattering data alone. DWBA calculations with a collective model form factor were performed for the inelastic scattering to the excited states. Coupled-channels calculations were also done both for the one-phonon and the two-phonon excited states. The optical model parameters were suitably modified to obtain simultaneous fit to elastic and inelastic data when channel coupling was introduced. The values of the vibrational parameter β₂ for one- and two-phonon states are discussed and compared with those obtained from γ-decay width studies.     

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.