Search results for "Nuclear cross section"

First measurement of the polarization observable E and helicity-dependent cross sections in single π 0 photoproduction from quasi-free nucleons

2017

The double-polarization observable $E$ and the helicity-dependent cross sections $\sigma_{1/2}$ and $\sigma_{3/2}$ have been measured for the first time for single $\pi^{0}$ photoproduction from protons and neutrons bound in the deuteron at the electron accelerator facility MAMI in Mainz, Germany. The experiment used a circularly polarized photon beam and a longitudinally polarized deuterated butanol target. The reaction products, recoil nucleons and decay photons from the $\pi^0$ meson were detected with the Crystal Ball and TAPS electromagnetic calorimeters. Effects from nuclear Fermi motion were removed by a kinematic reconstruction of the $\pi^{0}N$ final state. A comparison to data mea…

Antiproton-Proton Cross Sections at Small Momenta

1990

Since the startup of LEAR in 1983 we have undertaken a series of measurements of antiproton-proton cross sections for annihilation (pp → mesons)1, charge-exchange reaction (pp → nn)2, and elastic scattering (pp → pp)3,4. We have focussed our efforts of the measurements on the beam momentum range between 160 and 600 MeV/c. Our detector is optimized to handle the antiproton beam at very small momenta5. The liquid hydrogen target is placed in the vacuum tank, and the vacuum is directly connected to the beam line. The incident beam is defined by thin scintillators also placed in the vacuum. With the apparatus of these unique designs we have explored the beam momentum region below 300 MeV/c with…

What can be learnt about nuclear polarization from a consistency analysis ofe ? cross sections and muonic X-rays for208Pb and the isotone pair209Bi/2…

1977

A joint analysis of recent electron scattering cross sections and muonic atom X-ray energies is performed for208Pb and the isotone pair209Bi/208Pb. From the compatibility of the experimental data one can learn about the nuclear polarisation correction. However, we find this information not to be as accurate as other authors claimed when we take into consideration the ambiguities in the treatment of the corrections of the higher levels.

Incoherent diffractiveJ/Ψproduction in high-energy nuclear deep-inelastic scattering

2011

We compute cross sections for incoherent diffractive $J/\ensuremath{\Psi}$ production in lepton-nucleus deep-inelastic scattering (DIS). The cross section is proportional to $A$ in the dilute limit and to ${A}^{1/3}$ in the black disk limit, with a large nuclear suppression due to saturation effects. The $t$ dependence of the cross section, if it can be measured accurately enough, is sensitive to the impact parameter profile of the gluons in the nucleus and their fluctuations, a quantity that determines the initial conditions of a relativistic heavy-ion collision. The nuclear suppression in incoherent diffraction shows how the transverse spatial distribution of the gluons in the nucleus gra…

Test of a separable approximation to a local soft-core potential in the three-body system

1975

Three-nucleon observables below the break-up threshold are calculated employing the pole approximation to the soft-core Malfliet-Tjon potentials. The results are compared in detail to those obtained with the local potentials and to those calculated with the usual Yamaguchi interactions.

Comment on "Total Cross Section for Photon Absorption by Two Protons inHe3"

1995

3He electron scattering sum rules

1982

Electron scattering sum rules for3He are derived with a realistic ground-state wave function. The theoretical results are compared with the experimentally measured integrated cross sections.

A model study on the nuclear photoeffect

1977

In a simple model of a spinless particle moving in a finite square well potential influences of final state Born approximation and of various approximations in the electromagnetic operators on photoabsorption differential, total and integrated cross sections are investigated. While the Born approximation is very poor in all respects, the long wave length approximation turns out to be the best and reproduces the total cross section quite well. However, appreciable deviations occur in the differential cross section at intermediate energies. The integrated cross section slightly exceeds the classical sum rule resulting from nonanalyticity of the forward compton scattering amplitude, as is disc…

Relativistic corrections to the elastic electron scattering fromPb208

1976

In the present work we have calculated the differential cross sections for the elastic electron scattering from $sup 208$Pb using the charge distributions resulting from various corrections. The point proton and neutron mass distributions have been calculated from the spherical wave functions for $sup 208$Pb obtained by Kolb et al. The relativistic correction to the nuclear charge distribution coming from the electromagnetic structure of the nucleon has been accomplished by assuming a linear superposition of Gaussian shapes for the proton and the neutron charge form factor. Results of this calculation are quite similar to an earlier calculation by Bertozzi et al., who have used a different …

Determination of the total photo-absorption cross section of 197Au from () reaction cross sections

1984

Abstract Cross sections for the reactions 197Au ( γ, ℩ n ) (x ⩽ 12) have been measured for bremsstrahlung end-point energies in the range 60–340 MeV. From these dominant cross sections, the total photon absorption cross section is determined using a cascade-evaporation calculation to account for the missing reaction channels. The enhancement factor for the classical E1 sum rule is found to be 0.93 ± 0.10.