The angular distributions for deuteron photodisintegration have been measured in the energy region 140 – 400 MeV for recoil protons laboratory angles between 30° and 130°. The protons were analyzed in momentum with a magnetic spectrometer and detected by a counter hodoscope.
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Axis error includes +- 2/2 contribution.
This paper presents a large solid angle measurement of the positive pion absorption cross section on 4He and its decomposition into partial channels. The total absorption cross sections at incident pion kinetic energies of Tπ+=70, 118, 162, and 239 MeV are 35±5, 52±4, 51±5, and 27±2 mb, respectively. These values are lower than those reported in some previous experiments. At all pion energies a large fraction of the absorption cross section is due to multinucleon channels.
Data with (C=PRC) are taken from PR C56, 1872.
Results from a 4π solid angle measurement of the reactions 3He(π+,ppp) and 4He(π+,ppp)n at incident pion energies of Tπ+=70, 118, 162, 239, and 330 MeV are presented. For 3He the total absorption cross sections and their decomposition into two-proton and three-proton components are evaluated; for 4He the three-proton absorption cross sections are given. The differential distributions of the three-proton multinucleon absorption mode of both nuclei are analyzed and compared to each other by making use of a complete set of variables. The data are investigated for signatures of initial and final state interactions: it is found that more than half of the three-proton yield cannot be accounted for by cascade mechanisms. The remaining strength shows dependence on the incident pion angular momentum, but also structures that are not explained by simple semiclassical models.
Absorption cross section. Total errors are presented.
First and second errors are due to fits and normalization uncertainties, respectively.
First and second errors are due to fits and normalization uncertainties, respectively.
Results from a 4π solid angle measurement of the inclusive reaction (π+,π0) on 2H, 3He, and 4He at incident pion energies of Tπ+=70, 118, 162, 239, and 330 MeV are presented. The single charge exchange total cross sections were determined, and are compared to previous results and simple models of π–few-nucleon interactions. On the helium isotopes a strong damping of the cross sections in the Δ(1232) energy region is observed. Total cross sections of the breakup reaction π++2H →π+pn are also given.
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The production of K^+ mesons in pA (A = D, C, Cu, Ag, Au) collisions has been investigated at the COoler SYnchrotron COSY-Julich for beam energies T_p = 1.0 - 2.3 GeV. Double differential inclusive pC cross sections at forward angles theta < 12 degrees as well as the target-mass dependence of the K^+ momentum spectra have been measured with the ANKE spectrometer. Far below the free NN threshold at T_{NN}=1.58 GeV the spectra reveal a high degree of collectivity in the target nucleus. From the target-mass dependence of the cross sections at higher energies, the repulsive in-medium potential of K^+ mesons can be deduced. Using pN cross-section parameterisations from literature and our measured pD data we derive a cross-section ratio of sigma(pn -> K^+ X) / sigma(pp -> K^+ X) ~ (3-4).
Double differential cross section for P C --> K+ X obtained in the 1.3 T mode. Errors do not include systematic uncertainties.
Double differential cross section for P C --> K+ X obtained in the 1.6 T mode. Errors do not include systematic uncertainties.
Cross section ratios CU/C and AU/C measured with the 1.3 T mode. Errors include statistical and systematic uncertainties.
The first measurement of the p n -> d omega total cross section has been achieved at mean excess energies of Q = 28 and 57 MeV by using a deuterium cluster-jet target. The momentum of the fast deuteron was measured in the ANKE spectrometer at COSY-Juelich and that of the slow spectator proton p(sp) from the p d -> p(sp) d omega reaction in a silicon telescope placed close to the target. The cross sections lie above those measured for p p -> p p omega but seem to be below theoretical predictions.
Total cross sections after the P N --> DEUT OMEGA reaction just above threshold.
The pion absorption reaction (π+,3p) on Ar was studied at pion energies of 70, 118, 162 and 239 MeV, and on N and Xe at 239 MeV. The 3p cross secti
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Total neutron cross sections have been measured for the nuclei Be, C, O, Al, V, Mn, Co, Cu, Ag, Ce, Ta, Pb, Bi and U at 22 energies from 160 MeV to 575 MeV by the transmission method. The energy region contains the threshold for pion production. Different parametrizations of the experimental results are discussed. A test of charge symmetry was obtained from the proton- and neutron-induced cross sections on C and O, yielding 〈 (σ p − σ n ) σ p 〉 = 0.0012 ± 0.0059 .
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This paper reports on the charged pion production yields measured by the SPY/NA56 experiment for 450 GeV/c proton interactions on beryllium targets. The present data cover a secondary momentum range from 7 GeV/c to 135 GeV/c in the forward direction. An experimental accuracy ranging from 5 to 10%, depending on the beam momentum, has been achieved, limited mainly by the knowledge of the beam acceptance. These results will be relevant in the calculation of neutrino fluxes in present and future neutrino beams.
No description provided.
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