High resolution proton inelastic scattering from 50Cr

Resonances in the ⁵⁰Cr(p, p′γ) reaction were investigated with the TUNL high resolution system. All previously observed p-wave resonances between Ep = 2.00 and 3.03 MeV were studied. Measurement of the p' and the γ-ray angular distributions provides sufficient information to determine unambiguously the J-value of the resonance and the magnitude and relative phase of the inelastic decay amplitudes. Expressions are given for the appropriate angular distributions and for the transformation between the channel spin and the total angular momentum representation. Experimental results are presented for 24 p-wave resonances in ⁵¹Mn including decay amplitudes and relative phases for $\text{16}\text{3}\text{2}{}^{\mathrm{?}}$ resonances. Six resonances formerly assigned $\text{1}\text{2}{}^{\mathrm{?}}$ are reassigned $\text{3}\text{2}{}^{\mathrm{?}}$. Inelastic spectroscopic factors were determined for two analogue states. Proton strength functions were evaluated from both the elastic and inelastic data.     

Two-step process in proton inelastic scattering

Proton inelastic scattering exciting single-neutron states is calculated in the framework of the three-body model. The transition amplitude is approximately given by a sum of the one-step Born term and the pickup-stripping terms including the continuum p-n system propagation as well as the deuteron propagation in the intermediate state. The continuum contribution is not negligible at low energy and becomes as important as the terms at higher energies.     

Two-step processes in inelastic proton scattering

A discussion is given of effects ofp-d-p′ type two-step processes on inelastic scattering from¹⁶O and⁴⁰Ca with incident proton energies between E_p=25 and 46 MeV. It is found that the two-step processes increase the magnitude of the cross-section by about 20 % without altering the shape significantly.     

Azimuthal and single spin asymmetries in deep inelastic scattering

Azimuthal and single spin asymmetries play a crucial role in the study of the spin structure of hadrons in terms of their elementary constituents. Exploiting them to uncover information over subtle distribution and fragmentation functions, which cannot easily by accessed in other ways, is what this talk is about.     

Excitation of non-normal parity states in inelastic proton scattering

DWBA-calculations (differential cross section and polarization) of the inelastic proton scattering exciting non-normal parity states in ¹⁶O(2⁻, 8.88 MeV), ²⁸Si(3⁺, 6.27 MeV) and ³²S(1⁺, 4.70 MeV) have been performed assuming a pure spin-flip mechanism and using a mixture of 1p1h-configurations for the wave functions of the final states.     

Analyses of inelastic proton scattering from 20Ne

Differential cross sections and analyzing powers for inelastic proton scattering to the 2⁺₁, 4⁺₁ and 6⁺₁ states of ²⁰Ne are analyzed using an antisymmetrized distorted wave approximation in direct reaction theory. The spectroscopy of these states was obtained by angular momentum projection from an axially symmetric minimal-energy Hartree-Fock intrinsic state.     

Relativistic DWBA calculations for polarization transfer in proton inelastic scattering

The matrix element for inelastic scattering of protons leading to the excitation of collective states in even-even nuclei is calculated in the framework of Dirac phenomenology using a DWBA approach. The deformed parts of the Lorentz scalar and four-vector optical potentials serve as the transition operators. The results are compared with the recently measured polarization transfer coefficients on ⁴⁰Ca and ²⁰⁸Pb at 500 MeV. The agreement with experiment is good.     

Amplitude correlations for inelastic proton scattering from44Ca

The magnitudes and relative signs of inelastic proton channel amplitudes were determined for three decay channels for 53 5/2+ resonances in 45Sc. Although the reduced widths in each channel agree well with the Porter-Thomas distribution, large correlations are observed between widths and between amplitudes. The expected equality between the width correlation and the square of the amplitude correlation does not hold.     

Amplitude correlations for inelastic proton scattering from48Ti

The magnitudes and relative signs of inelastic proton channel amplitudes were determined for three decay channels for 45 5/2⁺ resonances in⁴⁹V. The reduced widths in each channel follow a Porter-Thomas distribution, but extremely large amplitude correlations are observed — for one pair of channel amplitudes the relative sign is positive for 43 of 45 resonances. These results provide the first direct test of the Krieger-Porter reduced width amplitude distribution.     

Theoretical investigation of giant resonances by inelastic proton scattering

A fully microscopic, antisymmetrized DWBA analysis of (p, p') spectra in the giant resonance region of ¹⁶O, ⁴⁰Ca and ²⁰⁸Pb is presented. The nuclear structure information is derived from RPA wave functions calculated in large configuration spaces. The theoretical spectra are in general in agreement with the experimental results. A new interpretation follows from our. investigation for the spectrum of the giant dipole region in the heavy nuclei: This resonance structure is mainly due to the breathing mode, whereas the electric dipole contribution is much smaller.     

A possible resolution of the proton spin problem

A number of lines of investigation into the structure of the nucleon have converged to the point where it seems possible to propose a consistent explanation of the well known proton spin problem.     

Spin dependence in inelastic proton scattering from odd-A nuclei

A DWBA analysis mixing single-particle and core excitations shows that the experimentally observed spin dependent effect in the inelastic proton scattering reflects an intermediate coupling situation in the structure of odd 2p, 1f-shell nuclei.     

Giant resonance effects in the analysing power from inelastic proton scattering

A simultaneous analysis of the analysing power and differential cross-section for the inelastic scattering of 30.4 MeV protons to the 2^?(8.88 MeV) state in ¹⁶O confirms the importance of two step components in the reaction mechanism. These important two step processes are those in which giant multipole resonances of the target are excited.     

Pick-up and inelastic scattering contributions to the proton optical potential

The contributions from couplings with the available inelastic (p, p′) and pick-up (p, d) channels to the elastic scattering of 30 MeV protons from ⁴⁰Ca, ⁴⁸Ca and ²⁰⁸Pb were studied. The equivalent non-local potentials were constructed and attempts were made to find local equivalents to them. These potentials are dependent upon angular momentum. Inelastic scattering produces an attractive contribution to the real potential but pick-up results in a much larger repulsive term. The main features of the observed scattering from ²⁰⁸Pb can be reproduced by coupling to 24 channels provided a supplementary absorptive term is included. The explicit couplings by themselves can produce 90 % of the observed absorption cross section but only about one-half of the empirical absorptive potential strength.     

The hydrogen hyperfine structure and inelastic electron proton scattering experiments

It is shown that present experiments on inelastic electron proton scattering can be used to set bounds to part of the proton polarizability contribution to the hyperfine structure of the ground state in the hydrogen atom.