M. L. Barlett

0.8 GeV p + Pb 208 elastic scattering and the quantity Δ r np

Analyses of 0.8 and 1 GeV p+/sup 208/Pb elastic angular distribution data have obtained neutron-proton root-mean-square radius differences (..delta..r/sub n/p) which are not consistent. Therefore, the 0.8 GeV experiment was repeated using a high resolution spectrometer. The new higher precision data are consistent with the older data, apart from a 15% overall normalization difference. A second order Kerman-McManus-Thaler optical model analysis of the new data, using a model-independent neutron density, yields ..delta..r/sub n/p=0.14 +- 0.04 fm, in good agreement with the most recent result obtained (0.16 +- 0.05 fm) from a similar analysis of the older 0.8 GeV data. In addition, the elastic angular distribution was extended to 42.5/sup 0/ center of mass in order to explore the momentum transfer region from 3.5 to 5.3 fm/sup -1/. Although the familiar diffraction pattern persists to 42.5/sup 0/, it was not possible within the framework of our application of the Kerman-McManus-Thaler optical model to fit the data even qualitatively at the larger momentum transfers.

Proton polarization observables for the elastic and inelastic scattering of 500 MeV protons from 40Ca and 208Pb

Abstract Measurements for the elastic and inelastic scattering of 500 MeV protons from 40 Ca and 208 Pb at small momentum transfers are reported. The induced proton polarization P and the spin rotation parameter Q were measured for the elastic scattering. The spin rotation parameters D SS ′ , D SL ′ , D LL ′ , d LS ′ and the induced polarization P were measured for transitions to the 3 − (3.37 MeV) and 5 − (4.48 MeV) states in 40 Ca and the 3 − (2.61 MeV) state in 208 Pb. Comparisons of the data with the theoretical calculations were carried out in the framework of nonrelativistic and relativistic approaches. We extracted the spin-up and spin-down channels for the elastic scattering cross sections and found that predictions of the relativistic and nonrelativistic approaches agree well with the spin-up channel data and differ considerably in the spin-down channel.

Polarized proton inelastic scattering from 40Ca and 48Ca at 500 MeV

Abstract Differential cross sections and analyzing powers for inelastic scattering of 500 MeV polarized protons to several low-lying states in 40 Ca and 48 Ca are presented. Phenomenological optical potentials (including density squared terms) have been determined and the data have been analyzed to obtain mass deformation parameters. It is expected that these data will be useful in further testing the recently developed relativistic impulse approximation formalisms and in studying the need for medium modification of the interaction.

Elastic scattering of 0.8 GeV polarized protons from 46,48Ti☆

Abstract Differential cross sections and analyzing powers for elastic scattering of 800 MeV polarized protons from 46,48Ti have been measured at laboratory angles ranging between 4° and 21°. The data are analyzed within the spin-dependent KMT formalism. Neutron density distributions are extracted and compared with the results of other experiments and with theoretical predictions. Disagreements between empirical results and DME calculations are found.

Inclusive (p, p′) cross sections and analyzing powers for 1H and 12C in the delta region☆

Abstract Cross sections and analyzing powers have been measured at 800 MeV for inclusive (p, p′) reactions on 1H and 12C in the 300 MeV excitation region. The data for 1H and 12C are qualitatively similar, but differ in detail. A Born approximation model reproduces the cross sections for p + p scattering, but fails to fit the Ay data. Further, while a plane wave impulse approximation calculation reproduces the general features of the 12C(p, p′) cross sections, significant details are not accounted for.

Low-momentum delta production in the 13C(p, d)12C∗ reaction☆

Abstract Cross sections for the reaction 13 C(p, d) 12 C ∗ in coincidence with back-to-back, out-of-plane, two-proton decays at high excitation energies (140–420 MeV) are presented for E p = 800 MeV at deuteron laboratory angles of 2.5°, 5.0°, and 9.0°. At all angles a resonant-like enhancement in the cross section is observed at 241 MeV of excitation energy with a width of 55 MeV. Some features of these data indicate that this structure may be related to the formation of low-spin (ΔN −1 ) states in 12 C.

Inclusive quasielastic spin observables for p+2H, 12C at 500 Me V☆

Abstract Analyzing powers (Ay) and spin-rotation-depolarization parameters (DSS, DSL, DLS, DLL, DNN) were determined for 500 MeV p + 2 H and p + 12 C inclusive quasielastic scattering at 10°, 15°, and 20° laboratory scattering angles. The p + 2 H data are consistent with the isospin-average of the proton-proton and proton-neutron scattering observables; the p + 12 C data are not. A relativistic plane wave impulse approximation calculation leads to better agreement with the p + 12 C spin-observables.

Nonrelativistic distorted wave born approximation predictions for 500 MeV (p, p') spin-rotation observables

Nonrelativistic distorted wave Born approximation spin-rotation [Dij] predictions for 500 MeV 40Ca, 208Pb(p, p) to the first 3− states are compared with data. Calculations based on the impulse approximation are unsuccessful, whereas a phenomenological effective interaction which accounts for elastic channel spin observables leads to excellent descriptions of the inelastic data. Distortion effects are examined and found to be fairly important.

Quasi‐free p↘+n analyzing powers at 800 MeV

The p↘+n analyzing power, Ay(θ), has been measured over the center‐of‐mass angular range 14–75 degrees.