Differential cross sections for elastic π−p scattering were measured at eight energies for positive pions and seven energies for negative pions. Energies ranged from 310 to 650 MeV. These measurements were made at the 3-GeV proton synchrotron at Saclay, France. A beam of pions from an internal BeO target was directed into a liquid-hydrogen target. Fifty-one scintillation counters and a matrix-coincidence system were used to measure simultaneously elastic events at 21 angles and charged inelastic events at 78 π−p angle pairs. Events were detected by coincidence of pulses indicating the presence of an incident pion, scattered pion, and recoil proton, and the results were stored in the memory of a pulse-height analyzer. Various corrections were applied to the data and a least-squares fit was made to the results at each energy. The form of the fitting function was a power series in the cosine of the center-of-mass angle of the scattered pion. Integration under the fitted curves gave values for the total elastic cross sections (without charge exchange). The importance of certain angular-momentum states is discussed. The π−−p data are consistent with a D13 resonant state at 600 MeV, but do not necessarily require such a resonant state.
No description provided.
No description provided.
No description provided.
Differential cross sections for the reaction π−p→π0n were measured at nine incident-pion kinetic energies in the interval from 500 to 1300 MeV. The negative pion beam from the bevatron was focused on a liquidhydrogen target completely surrounded by a cubic array of six steel-plate spark chambers. The spark chambers were triggered on events with neutral final states. Charge-exchange events were identified from the one-shower and two-shower events in the spark-chamber pictures. By the Monte Carlo technique, the π0 distributions were calculated from the bisector distributions of the two-shower π0 events together with the observed γ-ray distributions of the one-shower π0 events. These π0 distributions were fitted with both Legendre-polynomial expansions and power-series expansions by the method of least squares. The extrapolated forward differential cross sections are in good agreement with the dispersion calculations. The Legendre coefficients for the differential cross sections in isospin state T=12 were obtained by combining our results with available data on π±p elastic scattering. In the light of existing phase-shift solutions, the behavior of these coefficients is discussed. The D5F5 interference term that peaks near 900 MeV is verified to be in isospin state T=12 only. We report here also the total neutral cross sections and the cross sections for the production of neutral multipion final states 2π0n and 3π0n. The 4π solid angle and the calibrated energy response of the spark chambers contribute to the accuracy of the results.
No description provided.
No description provided.
No description provided.
Total cross sections of π+ and π− mesons on protons and deuterons have been measured in a transmission experiment to relative accuracies of ±0.2% over the laboratory momentum range 0.46-2.67 GeV/c. The systematic error is estimated to be about ±0.5% over most of the range, increasing to about ±2% near both ends. Data have been obtained at momentum intervals of 25-50 MeV/c with a momentum resolution of ±0.6%. No new structure is observed in the π±p total cross sections, but results differ in several details from previous experiments. From 1-2 GeV/c, where systematic erros are the smallest, the total cross section of π− mesons on deuterons is found to be consistently higher than that of π+ mesons by (1.3±0.3)%; about half of this difference may be understood in terms of Coulomb-barrier effects. The πd and πN total cross sections are used to check the validity of the Glauber theory. Substantial disagreements (up to 2 mb) are observed, and the conclusion is drawn that the Glauber theory is inadequate in this momentum range.
No description provided.
No description provided.
Approximately 700 events of the reaction K − d → K − π − pp s produced by 5.5 GeV/ c kaons were used to measure the cross section for Kπ elastic scattering in the T = 3 2 state by a Chew-Low extrapolation. The cross section does not exceed 2.1 mb and has no structure for Kπ masses from threshold up to 2.0 GeV.
Chew-Low extrapolation is used for evaluation of the K- P elastic cross section.
The total cross section of γ rays in hydrogen resulting in hadron production, σT, has been measured over the energy range 265-4215 MeV. A tagging system with narrow energy bins was employed. Structure in the resonance region followed by a steady fall with energy has been observed and the results are analyzed. The forward amplitude of γ-proton scattering is evaluated, and its behavior in the Argand diagram studied as a function of energy. The relationships of the measurements to Regge-pole theory and the vector-dominance model are detailed.
No description provided.
SPIN AVERAGED FORWARD COMPTON SCATTERING AMPLITUDE. IM(AMP) WAS CALCULATED VIA THE OPTICAL THEOREM FROM A SMOOTH FIT TO THE DATA, AND USED IN THE DISPERSION RELATION TO CALCULATE RE(AMP). AT THRESHOLD THE THOMSON AMPLITUDE IS -3.0 MUB*GEV.
The total cross sections of π± on protons in the momentum interval from 0.40 to 0.90 GeV/c have been measured with high relative precision. In this interval the statistical error varies between 10 and 20 μb. No new structure is observed.
No description provided.
None
STATISTICAL ERRORS ONLY.
The total electromagnetic cross sections of g-rays in hydrogen and deuterium have been measured over the energy range 265–4215 MeV using a photon tagging system. From these measurements, the total pair production cross sections are obtained, and the results are found to be in good agreement with the predictions of Jost, Luttinger and Slotnick.
Axis error includes +- 1/1 contribution.
Axis error includes +- 1/1 contribution.
The total cross section for photoproduction of hadrons on the deutron, σ T d , has been measured for photon energies in the range 0.265–40215 GeV. From this, using results for the photon total cross section, obtained previously with the same apparatus, the neutron total cross section has been determined in the resonance region. The resonant structure is found to be quite different from that for the proton. Thereafter the neutron cross section falls off steadily with energy, and the values obtained are consistently lower than those for the proton. Forward scattering amplitudes have been evaluated for the deuteron.
No description provided.
RESONANCE REGION. UNSMEARING CORRECTION APPLIED, GLAUBER CORRECTION NEGLIGIBLE.
HIGHER ENERGY CROSS SECTIONS, IN 200 MEV BINS. OVERALL 3 PCT SYSTEMATIC ERROR IN ADDITION TO QUOTED STATISTICAL ERRORS. NEUTRON/PROTON CROSS SECTION RATIO HAS MEAN VALUE OF 0.94 +- 0.01.
The proof is given for the existence of the reaction e + e − → h ± h ∓ in the energy range 1400–2400 MeV, and its energy dependence is compared with that of e + e − → e ± e ∓ , in the same experimental conditions of observation. The exponent of the s -dependence of the ratio α = (e + e − → h ± h ∓ )/ (e + e − → e ± e ∓ ) is measured to be n = 2.08 ± 0.45, in the s -range (1.96 − 5.76) GeV 2 , on the basis of 51 e + e − → h ± h ∓ events and 8918 e + e − → e ± e ∓ events observed.
CROSS SECTION FOR PRODUCTION OF CHARGED HADRON PAIRS.
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