Employing a neutral kaon beam at the Argonne Zero Gradient Synchrotron, a high-resolution magnetic spectrometer, and a neutron detector, differential cross sections have been obtained in the forward direction [0.045<|t|<0.18 (GeV/c)2] for the reaction KL0p→K+n. Previous studies of the time-reversed process in deuterium, K+d→K0p(p), have not yielded direct cross-section measurements in the forward direction because there is an inhibition of the non-spin-flip process in deuterium due to the Pauli exclusion principle. Nevertheless, our data are in agreement with the extracted free-neutron cross sections of deuterium studies as determined from the impulse and closure approximations.
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The reactions e + d → e ' + p S + p + π − and e + d → e ' + n S + n + π + were measured detecting electron and pion in coincidence at an invariant hadronic mass of 2.19 GeV. The measurements were performed at electron four-momentum transfer squared of f 2 = 0.70 and 1.35 GeV 2 in the range of t = ( γ v − π ) 2 between t min and −1.0 GeV 2 . The cross section d 2 σ / dtdφ of the reaction e + n → e' + p + π − was determined.
ACTUALLY RATIO OF PI- TO PI+ PRODUCTION OFF DEUTERIUM.
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An analysis of the Kπ-system in the mass region of the K ∗ (1780), based on a sample of 46000 K s o π + final states, is presented. Evidence for a relatively narrow width, τ ≈ 100 MeV, and for the spin parity assignment J P = 3 − is found.
SLOPE DETERMINED WITHIN 0.2 < -T < 0.8 GEV**2 AND USED TO ESTIMATE TOTAL CROSS SECTION.
The production of multipion events by e + e − annihilation has been measured at centre of mass energies 915,990 and 1076 MeV. Both channels e + e − → π + π − π o and e + e − → π + π − π + π − have been analysed. An energy threshold effect analysed. An energy threshold effect around 919 MeV ( m ω + m π o ) has been evidenced for the π + π − π o π o channel and the cross section is consistent with the quasi two-body process e + e − → ωπ o . The cross section for π + π − π + π − is lower by an order of magnitude and increases with the energy.
SYSTEMATIC ERROR INCLUDED. RADIATIVE EFFECT (<15 PCT) INCLUDED.
MULTIHADRON PRODUCTION CROSS SECTION DEDUCED AS SUM OF FOUR PION CHANNELS.
A partial wave analysis of the K 0 π + π − system produced in the charge exchange reaction K − p → ( K 0 π + π − ) n at 4.2 GeV/ c has been performed both as a function of Kππ mass and of t ′. The 1 + S wave forms the largest contribution to the K ππ system and peaks at roughly the same mass as the Q in diffractive K ππ production. The polarization properties of the 1 + S ( K ∗ π) and 1 + S (Kϱ) waves differ fromt those of the diffractive 1 + wave. There is some evidence for a resonance contribution to 1 + S ( K ∗ π) . The strong 2 + wave the K ∗ (1420) and the K ϱ/ K ∗ ϱ decay branching ratio determined to be 0.36±0.10. An enhancement with spin-parity 1 − is observed under K ∗ (1420) .
CROSS SECTION CORRECTED FOR BREIT-WIGNER TAILS, THE TP CUT, UNSEEN <AK0 PI> AND <K RHO> DECAY MODES. BRANCHING RATIO K*(1420) --> <K RHO>/<K* PI> = 0.36 +- 0.10.
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Measurements of the polarised beam asymmetry parameter Σ for eta photoproduction from protons, have been carried out at incident energies of 2.5 GeV and 3.0 GeV, and for various t -values between −0.2 (GeV/c) 2 and −1.2 (GeV/c) 2 . The values of Σ are close to +1 for values of | t | less than 0.7 (GeV/c) 2 , showing that there can be little contribution from unnatural parity exchange in any Regge exchange model of the process, in disagreement with present theories. Differential cross sections for the process werre also measured, and are consistent with those from other experiments.
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Elastic scattering of 32.1 GeV/ c K + on protons has been measured in a bubble chamber experiment. Results are presented in the momentum transfer interval 0.06–1.40 GeV 2 and compared with data at different energies. An effective Regge trajectory is calculated using K + p elastic data from 10 to 175 GeV/ c .
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The Λ p total cross section has been measured in the Λ momentum range 4–14 GeV/c. The weighted mean of the cross section over this momentum interval is σ( Λ p) = 49.3 ± 3.7 mb for an average Λ momentum of 8.3 ± 2.7 GeV/ c . This value differs from the corresponding value for σ(Λp) measured previously by 14.5 ± 3.8 mb. Assuming a variation with Λ momentum, pΛ , of the form σ( Λ p) − σ(Λp) = σ 1pΛ − 1 2 , a value of σ 1 = 47 ± 10 mb GeV − 1 2 is obtained.
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Elastic and inelastic scattering of 1.044 GeV protons have been studied on isotopically enriched even 40, 42, 44, 48 Ca isotopes and 48 Ti. A spin independent Glauber theory analysis of the elastic scattering allowed the extraction of neutron and nuclear matter densities for these targets.
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The results of a study of the reaction π-p→π-π-π+p at2 147 GeV/c carried out at the Fermilab Proportional Wire 30″ Bubble Chamber Hybrid Spectrometer are reported. More than 92% of the cross-section ((670±41) μb) for this reaction is contained in those for proton and pion diffraction dissociation. The cross-sections for pion diffraction events with three-pion invariant mass in given regions are in agreement with values obtained by extrapolation of fits to data at lower incidentpion momenta. ρ0π- events make an important contribution in the A1 and A2 mass regions, and the data are consistent with contributions from f0π- in the A3 mass region. The cross-section for proton diffraction events is in agreement with a smooth extrapolation of the data at lower momentum.
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