Systematics of the isoscalar giant monopole resonance from 60 MeV inelastic proton scattering

Evidence for an isoscalar giant monopole resonance is provided for seven nuclei with A ? 58. The resonance excitation energy is $\text{≈ 80 × A}{}^{\mathrm{<mtext>?1</mtext><mtext>3</mtext>}}\text{MeV}$. For nuclei with A ? 0, nearly 100% of the L = 0, T = 0 energy-weighted sum rule is depleted in the resonance, in agreement with earlier work on ²⁰⁸Pb and ¹⁴⁴Sm. Only ≈30% is found in ⁵⁸Ni, and no clear evidence is found for localized monopole strength in ⁴⁰Ca.     

Excitation of the isoscalarE2 resonance in12C by proton inelastic scattering

Proton inelastic excitation spectra of¹²C have been measured imposing a coincidence with alpha decay to⁸Be_g.s. and⁸Be_2.9MeV. In plane angular correlations have been obtained for the main structures observed in the spectra. Comparison with DWBA correlation functions permits a 2⁺ assignment for all the groups in the 20–30MeV excitation range. The percentage of theE2-EWSR exhausted in the same range is in agreement, within the uncertainties indicated, with that derived from the inelastic scattering of other particles.     

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.     

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.     

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.     

Interference effects in inelastic proton scattering on 28Si

Interference effects in ²⁸Si(p, p') inelastic scattering are studied in the Coulomb barrier region. The interference occurs between compound contributions and direct inelastic transitions. The asymmetric resonance shape is analysed to extract the intrinsic shape of the excited target nucleus.     

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.     

Spin-dependent effects in inelastic scattering

The differential cross sections for the inelastic scattering of 10 MeV, 19.6 MeV, 30.4 MeV, 40 MeV and 49.35 MeV protons to the 2⁺ state (1.409 MeV) in ⁵⁴Fe and of 19.6 MeV protons to the 2⁺ state (0.846 MeV) in ⁵⁶Fe are analyzed in conjunction with the available data on the asymmetries and spin-flip probability amplitudes. The scattering amplitudes for both one step (valence plus core polarization) and two step (intermediate resonance) processes are evaluated using an antisymmetrized distorted wave approximation. Collective model representations for both the one step (core polarization) and two step (intermediate resonance) processes are used, and included are the effects of deforming the full Thomas spin-orbit potentials. The one step processes are fixed by the analyses of the scattering of 30.4, 40 and 49.35 MeV protons, with the core polarization contributions being constrained by the B(E2) values for the γ-ray deexcitation of the 2⁺ states. The analyses of the 19.6 MeV data demonstrates the need for an extra (two step) contribution to the reaction process and are consistent with the virtual formation of an L = 3 giant resonance. The 10 MeV data most certainly demonstrate compound nucleus effects but could also have some strength due to the virtual formation of an intermediate L = 2 giant resonance. The resonance parameters are consistent with recent information concerning the mass variation of giant resonances.     

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.     

Nuclear spin response to inelastic proton scattering: Finite geometry and absorption effects

Recent experiments have clearly demonstrated the ability of inelastic proton scattering to act as a precise probe of the nuclear spin response. Previous calculations based on infinite or semi-infinite matter models differ markedly from experiment in their prediction of longitudinal to transverse response function ratios. The present work indicates that finite geometry and absorption effects are crucial in bringing predictions closer to experiment. The effect of including isobar excitations is also investigated and assessed critically.     

Pionic effects in inelastic electron-nucleus scattering

We calculate the structure functions for deep inelastic electron scattering on baryons in a two-dimensional model which incorporates pionic degrees of freedom explicitly. We analyze the behavior of these structure functions in the Bjorken limit and conclude that scaling and Regge behavior are satisfied. A trivial extension as a parton model can be achieved by just introducing the structure functions for the pion. We next generalize our calculation to nuclear matter and study the behavior of such a system under electron scattering. Scaling but not Regge behavior appears in the Bjorken limit. The diverse behavior in these two situations is carefully analyzed. Most of the results obtained in this paper are qualitatively independent of the dimensions of the model and therefore will hold in its four-dimensional generalization.     

Spin effects in inelastic proton-nucleus scattering

We include the spin-orbit force in the analysis of inelastic proton-nucleus scattering. In the limit of zero-range nuclear forces, very simple results are obtained. To lowest order in the elementary spin-orbit amplitude, the spin-dependent nuclear amplitudes are proportional to the momentum transfer times the spin-independent nuclear amplitudes. Consequently, in the spin-independent cross section the region of the diffractive minima is not significantly affected by the elementary spinorbit amplitudes, whereas the subsidiary maxima are somewhat enhanced.     

Coherence effects in deep inelastic scattering

A superfield action for the relativistic massless superparticle as a spinning particle is presented in the new gauge. The symmetries in the relativistic superparticle theory, that is to say, the invariances under, the reparametrization and the local supersymmetry-transformation in the parameter space, are manifest in this formalism. It is clear how these two kinds of transformations descend from a unified origin to be called “super-reparametrization”, which is a restricted form of the general coordinate transformation in the superspace. The action is manifestly invariant under these transformation by its constructions The minimal coupling with electromagnetic field is also constructed in the superfield formalism, and a manifestly invariant superfield action for the interacting superparticle is presented in our gauge. The formalism is extended to the construction of an action for theN=2 superparticle.     

On the excitation of isovector dipole strength by inelastic proton scattering in the giant resonance region in light nuclei

A detailed comparison between inelastic α and p scattering in the giant resonance region of ^{24, 26}Mg, ²⁸Si and ⁴⁰Ca shows that there is no evidence for ΔT = 1, E1 excitation in the (p, p′) spectra. This is consistent with DWBA calculations using a recently obtained isovector interaction potential.