We have measured the differential cross-section and the analyzing power (polarization) for p-He4 elastic scattering at incident kinetic energies of 0.56, 0.80, 1.03, 1.24, and 1.73 GeV. The experiment used a polarized proton beam incident on a liquid helium target and a single arm magnetic spectrometer to detect elastic scattering. Both the differential cross sections and the analyzing power show structure near −t=0.25 (GeV/c)2 which decreases in magnitude with increasing energy. Both multiple scattering and optical model interpretations of the data are discussed. NUCLEAR REACTIONS elastic scattering, p-He4; GeV energies; measured differential cross section; measured polarization; comparison with theory.
No description provided.
No description provided.
No description provided.
None
Measured Quasi-Elastic total cross section.
Radiation capture of π − on hydrogen has been measured in the momentum range from p π − = 210 MeV/ c to p π − = 385 MeV/ c and for c.m. angles between 30° and 120°, covering the Δ (1232) resonance. The unambiguous separation of the events from the charge exchange background is based on precise neutron time-of-flight measurements. Detector efficiencies were carefully determined in separate experiments. The experimental results are in good agreement with those of the inverse reaction and with most recent multipole analyses. An upper limit of ±2% can be set on the contribution of the isotensor term to the transition amplitude. A time reversal violating phase, when added to the resonant M 1+ 3 amplitude in the Donnachie-Shaw model, is found to be consistent with zero.
This results was extracted from the cross sections for the inverse reactionPI- P --> GAMMA N via detailed balance by applying relation: D(SIG(GAMMA))/D(OM EGA)=D(SIG(PI-))/D(OMEGA)*P(PI)**2/2/P(GAMMA)**2.
The reaction pn→ppπ at 19 GeV/c is studied. It is dominated by the process where the neutron dissociates into the pπ- system and exhibits the characteristic features of diffraction dissociation. The pπ- mass distribution shows a strong peak at 1.3 GeV but is otherwise rather structureless. By comparison with other experiments we find that this peak is neither seen at higher nor at lower energies. The reason why it is not seen in experiments at higher energies seems to be that they suffer from strong experimental limitations. The 1.3 GeV peak is connected with small momentum transfers and an analysis of the moments of the decay angular distributions shows that this peak is a low-spin phenomenon. For larger momentum transfers the lowest moments show an onset already at threshold. By comparison with a pion exchange Deck model we find a substantial baryon exchange contribution for small momentum transfers. This contribution seems to become more pronounced at higher energies.
CORRECTED FOR UNOBSERVED DECAY MODES.
The polarization in π + p → π + p and K + p → K + p has been measured at 6 and 12 GeV/ c in the four-momentum transfer interval 0.1 ⩽ | t | ⩽ 2.0 (GeV/ c ) 2 by scattering on protons of a polarized deuteron target. Comparison with existing results obtained with polarized proton targets shows good general agreement and no evidence for asymmetry effects due to the presence of the spectator neutron. For K + p elastic scattering polarization the experiment yields improved statistics, especially at 6 GeV/ c
No description provided.
No description provided.
No description provided.
Inclusive measurements of Λ 0 , Λ 0 , Ξ − , Σ(1385) ± ) production in the forward direction at the CERN intersecting storage rings are presented. A signal for simulataneous Λ 0 Λ 0 production is also observed with total x > 0.6, 2.3 < M Λ Λ < 2.5 GeV and with a cross section of (1.7 ± 0.2) μb.
No description provided.
No description provided.
No description provided.
We report the first measurement of the ratio R=(σe+e−→hadrons)(σe+e−→μ+μ−) (with negligible τ-lepton contribution) at a center-of-mass energy s=13 GeV and s=17 GeV, from the just finished electron-positron colliding-beam facility PETRA. The detector, MARK-J, has an approximately 4π solid angle and measures γ, e, μ, and charged and neutral hadrons simultaneously. Our results yield R(s=17 GeV)=4.9±0.6 (statistical) ±0.7 (systematic error), and R(s=13 GeV)=4.6±0.5 (statistical) ±0.7 (systematic error). The ratio R(s=17 GeV)R(s=13 GeV) is 1.08±0.18.
No description provided.
No description provided.
We have studied inclusiveΔ++ (1232),∑+ (1385), and∑− (1385) baryon resonance production inK−p interactions at 32 GeV/c. The inclusive and topological cross sections are estimated and compared with published results at lower energies. No energy variation of the cross section is observed forΔ++ (1232) and only a slight decrease is seen in case of∑± (1385). The production properties are investigated through longitudinal and transverse momentum distributions. TheΔ++ (1232) is dominantly produced in the target fragmentation region. The∑+ (1385) is produced both in the target fragmentation region and in the central region, while the∑− (1385) is predominantly produced in the central region. About 20% of the final state protons are produced via aΔ++ (1232) decay and about 25% of the Λ produced come from the decay of∑+ (1385) and∑− (1385).
No description provided.
No description provided.
No description provided.
This paper summarizes the measurements one+e− annihilation performed by the DASP Collaboration in the energy range between 3.1 and 5.2 GeV. The following topics are covered: total cross section, production and two body decays of the narrow resonances, radiative decays of theJ/ψ and ψ′ resonances and evidence for theX(2.82), ψ′ cascade decays, inclusive η production and evidence for theF meson, semileptonic decays of charmed mesons and properties of the heavy lepton.
THESE DATA ON R WERE PUBLISHED IN R. BRANDELIK ET AL., PL 76B, 361 (1978), THE RECORD OF WHICH HAS TABULATED CROSS SECTIONS WITH AND WITHOUT THE TAU HEAVY LEPTON CONTRIBUTION.
OBSERVATION OF J/PSI RESONANCE.
OBSERVATION OF PSI(3700)0 RESONANCE.
None
X ERROR D(-T)/(-T) = 2.0000 PCT.
X ERROR D(-T)/(-T) = 2.0000 PCT.
Forum