Nucl.Phys.A706:403-417,2002 The cross section for the $^3$He(e, e$'$d)p reaction has been measured as a
function of the missing momentum $p_m$ in q$\omega$ -constant kinematics at
beam energies of ...370 and 576 MeV for values of the three-momentum transfer $q$
of 412, 504 and 604 \mevc. The L(+TT), T and LT structure functions have been
separated for $q$ = 412 and 504 \mevc. The data are compared to three-body
Faddeev calculations, including meson-exchange currents (MEC), and to
calculations based on a covariant diagrammatic expansion. The influence of
final-state interactions and meson-exchange currents is discussed. The
$p_m$-dependence of the data is reasonably well described by all calculations.
However, the most advanced Faddeev calculations, which employ the AV18
nucleon-nucleon interaction and include MEC, overestimate the measured cross
sections, especially the longitudinal part, and at the larger values of $q$.
The diagrammatic approach gives a fair description of the cross section, but
under(over)estimates the longitudinal (transverse) structure function.
To investigate the importance of three-nucleon forces (3NF) systematically over a broad range of intermediate energies, the differential cross sections of elastic proton-deuteron scattering have been ...measured at proton bombarding energies of 108, 120, 135, 150, 170 and 190 MeV at center-of-mass angles between \(30^\circ\) and \(170^\circ\). Comparisons with Faddeev calculations show unambiguously the shortcomings of calculations employing only two-body forces and the necessity of including 3NF. They also show the limitations of the latest few-nucleon calculations at backward angles, especially at higher beam energies. Some of these discrepancies could be partially due to relativistic effects. Data at lowest energy are also compared with a recent calculation based on \chipt.
The isoscalar giant dipole resonance (ISGDR) has been investigated in 208Pb using inelastic scattering of 400 MeV alpha particles at forward angles, including 0deg. Using the superior capabilities of ...the Grand Raiden spectrometer, it has been possible to obtain spectra devoid of any "instrumental" background. The ISGDR strength distribution has been extracted from a multipole-composition of the observed spectra. The implication of these results on the experimental value of nuclear incompressibility are discussed.
Decay via proton emission of isobaric analog states (IAS's) in \(^{91}{Nb}\) was studied using the \(^{90}{Zr}(\alpha,t)\) reaction at \(E_\alpha\)=180 MeV. This study provides information about the ...damping mechanism of these states. Decay to the ground state and low-lying phonon states in \(^{90}{Zr}\) was observed. The experimental data are compared with theoretical predictions wherein the IAS `single-particle' proton escape widths are calculated in a continuum RPA approach. The branching ratios for decay to the phonon states are explained using a simple model.
Discrete Gamow-Teller (GT) transitions, 176Yb-->176Lu at low excitation energies have been measured via the (3He,t) reaction at 450 MeV and at 0 degrees. For 176Yb, two low-lying states are observed, ...setting low thresholds Q(neutrino)=301 and 445 keV for neutrino capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q(neutrino) in Yb--Lu indicate that Yb-based neutrino-detectors are well suited for a direct measurement of the complete sub-MeV solar electron-neutrino spectrum (including pp neutrinos) where definitive effects of flavor conversion are expected.
The cross section for the \(^3\)He(e, e\('\)d)p reaction has been measured as a function of the missing momentum \(p_m\) in q\(\omega\) -constant kinematics at beam energies of 370 and 576 MeV for ...values of the three-momentum transfer \(q\) of 412, 504 and 604 \mevc. The L(+TT), T and LT structure functions have been separated for \(q\) = 412 and 504 \mevc. The data are compared to three-body Faddeev calculations, including meson-exchange currents (MEC), and to calculations based on a covariant diagrammatic expansion. The influence of final-state interactions and meson-exchange currents is discussed. The \(p_m\)-dependence of the data is reasonably well described by all calculations. However, the most advanced Faddeev calculations, which employ the AV18 nucleon-nucleon interaction and include MEC, overestimate the measured cross sections, especially the longitudinal part, and at the larger values of \(q\). The diagrammatic approach gives a fair description of the cross section, but under(over)estimates the longitudinal (transverse) structure function.
PDF