0000000000323111
AUTHOR
V. Isbert
Study of three-nucleon mechanisms in the photodisintegration of 3He
Abstract The cross section of the 3He(γ,pp)n reaction has been measured for the first time over a wide photon energy and proton angular range (200 MeV ≤ Eγ ≤ 800 MeV; 20° ≤ ϑplab ≤ 160°) using the large acceptance detector DAPHNE at the tagged photon facility of the MAMI microtron in Mainz. The wide kinematical coverage of the measurement has allowed a detailed analysis of three-nucleon absorption mechanisms. A model developed by Laget explains the main characteristics of the data in the Δ resonance region.
Photon Asymmetry of Deuteron Photodisintegration Between 160 and 410 MeV
The photon asymmetry Σ of the reaction has been measured across the photon energy range 160–410 MeV at the Mainz Microtron MAMI. Linearly polarized photons were obtained from coherent bremsstrahlung and their energies were determined with the Glasgow tagging spectrometer. The large acceptance detector DAPHNE enabled the outgoing protons to be measured over the complete azimuthal range and for polar angles from 35° to 155° in the c.m. system. The data are compared with existing results and recent theoretical calculations.
Total photoabsorption cross sections forH1,H2, andHe3from 200 to 800 MeV
The total photoabsorption cross sections for $^{1}\mathrm{H}$, $^{2}\mathrm{H}$, and $^{3}\mathrm{He}$ have been measured for incident photon energies ranging from 200 to 800 MeV. The $^{3}\mathrm{He}$ data are the first for this nucleus. By using the large acceptance detector DAPHNE in conjunction with the tagged photon beam facility of the MAMI accelerator in Mainz, cross sections of high precision have been obtained. The results show clearly the changes in the nucleon resonances in going from $^{1}\mathrm{H}$ to $^{3}\mathrm{He}$. In particular, for the ${\mathit{D}}_{13}$ region the behavior for $^{3}\mathrm{He}$ is intermediate between that for $^{1}\mathrm{H}$, $^{2}\mathrm{H}$, and h…
Total cross section measurement for the three double pion photoproduction channels on the proton
Abstract The total cross sections for the three γp → Nππ reactions have been measured for photon energies from 400 to 800 MeV. The γ p → p π 0 π 0 and γ p → n π + π 0 cross sections have never been measured before while the γ p → p π + π − results are much improved compared to earlier data. These measurements were performed with the large acceptance hadronic detector DAPHNE, at the tagged photon beam facility of the MAMI microtron in Mainz.
Two-body photodisintegration of the deuteron from 100 to 800 MeV
Abstract The total and the differential cross sections for the D(γ,p)n reaction have been measured over the photon energy range 100-800 MeV at the 855 MeV MAMI Microtron in Mainz. Using the large acceptance detector DAPHNE in conjunction with the Glasgow tagging spectrometer, high precision results with small systematic errors were obtained. The data are presented in the form of thirty-five angular distributions at c.m. proton angles between 30°–160° in 10° intervals and at photon energies in steps of 20 MeV. Previous experimental work is reassessed in the light of the present results and comparison with some recent theoretical calculations.
Total photoabsorption cross section for4He from 200 to 800 MeV
The total photoabsorption cross section for ${}^{4}$He has been measured for the first time over a wide photon energy range (200 MeV$l~{E}_{\ensuremath{\gamma}}l~$800 MeV). By using the large acceptance detector DAPHNE at the tagged photon facility of the MAMI microtron in Mainz high precision results with small systematic errors were obtained. This measurement shows that ${}^{4}$He has a behavior similar to heavy nuclei and, in particular, a reduction of the cross section with respect to the lighter nuclei is found for ${E}_{\ensuremath{\gamma}}g$600 MeV.
Measurement of theE2/M1Ratio in theN→ΔTransition Using the Reactionp(γ→,p)π0[Phys. Rev. Lett. 78, 606 (1997)]
The small electric quadrupole $E2$ amplitude of the predominantly magnetic dipole $M1$ $p\ensuremath{\rightarrow}\ensuremath{\Delta}(1232)$ transition has been measured using 270 to 420 MeV tagged linearly polarized photons in the $p(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}},p){\ensuremath{\pi}}^{o}$ reaction at the Mainz Microtron MAMI. Differential cross sections and photon asymmetries were determined by measuring the recoil proton in the cylindrically symmetric $4\ensuremath{\pi}$ detector DAPHNE. From the proton angular distributions the ratio $E2/M1\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}(2.5\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\…
Double Pion Photoproduction on the Proton up to 800 MeV
The total cross sections for the three γp → N ππ reactions have been measured for photon energies from 450 to 800 MeV. The γp → pπ0π0 and γp → nπ+π0 rcross sections have never been measured before while the γp → pπ+π− results are much improved compared to earlier data. These measurements were performed with the large acceptance hadronic detector DAPHNE, at the tagged photon beam facility of MAMI microtron in Mainz.
"Table 1" of "Total photoabsorption cross-section for He-4 from 200-MeV to 800-MeV"
No description provided.