Total cross sections of p¯p and p¯d have been measured between 360 and 1050 MeV/c, with high statistical precision. Structures are observed in both cross sections at about the same momenta. For p¯p, the central mass is 1932±2 MeV/c2, and a fit to the data with a simple Breit-Wigner resonance plus background gives Γ=9−3+4 MeV/c2. The data suggest that the structures are in the isospin-1 state.
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The charged-particle multiplicity distribution in 205−GeVc proton-proton interactions is presented. In addition, the total diffractive contributions to each charged multiplicity are estimated assuming a factorizable Pomeron.
THE TOTAL CROSS SECTION NORMALIZATION COMES FROM THIS AND OTHER EXPERIMENTS.
We have observed a second sharp peak in the cross section for e+e−→hadrons at a center-of-mass energy of 3.695±0.004 GeV. The upper limit of the full width at half-maximum is 2.7 MeV.
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TWO EVENTS SEEN WITH MASSES 800 +- 90 MEV AND 1400 +- 90 MEV. THE FIRST WHEN INTERPRETED AS ETAPRIME PRODUCTION GIVES A WIDTH OF 11, +15, -8 KEV FOR ETAPRIME --> 2GAMMA USING THE EQUIVALENT PHOTON APPROXIMATION.
At the Bonn 2.5 GeV synchrotron the differential photoproduction cross section d σ /d t of φ mesons has been measured at a photon energy of 2.0 GeV at fibe different t values between 0.23 < | t | < 0.73 (GeV/ c ) 2 . The φ meson was detected by magnetic momentum analysis of both charged decay K mesons and by a time of flight and angle measurement of the coincident recoil proton. We found an exponential behaviour for the t dependence of the cross section. The measured slope of the exponential decrease was b = (4.01 ± 0.23) (GeV/ c −2 . This result, combined with previous measurements at higher energies, implies that the slope of the pomeron trajectory is compatible with zero. In addition the experiment yielded a value of the φ mass, m φ = (1019.4 ± 0.8) MeV and a value of the φ width, Γ = (4.4 ± 0.4) MeV.
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In an experiment with the CERN 2 metre DBC the reaction K$^+$d $\to$ K$^0 \pi^+$d is studied at an incident momentum of 4.6 GeV/c. The cross section is found to be (66 ± 10) μb for four-momentum transfer squared from target to recoil deuteron greater than 0.02 GeV 2 , and the reaction is dominated by the production of K$^*+$ (892) via natural parity exchange. Using data for the reactions K$^\pm$d $\to$ K$^{*\pm}$(892)d in the incident momentum range 2–13 GeV/ c the parameters of the effective exchanged trajectory are estimated.
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About 45000 interactions of antiprotons of kinetic energy between 57 and 170 MeV have been measured in a deuterium bubble chamber. Total and annihilation cross-sections have been determined at 9 values of the antiproton energy together with the differential crosssection dσ/dt for scattering events. In spite of the peculiar behaviour of the deuteron target at these low energies a reliable measure of the antiproton-neutron annihilation cross-section has been obtained.
INELASTIC (ANNILATION + CHARGE EXCHANGE), SCATTERING (ELASTIC + INELASTIC) AND TOTAL CROSS SECTIONS. AUTHORS ALSO GIVE TOPOLOGICAL DECOMPOSITION OF THESE CROSS SECTIONS.
SCATTERED ANTIPROTON ANGULAR DISTRIBUTION. THE OPTICAL POINT AT T=0 IS CALCULATED FROM THE TOTAL CROSS SECTION. SEPARATION INTO SCATTERING ON PROTONS AND ON NEUTRONS IS IMPOSSIBLE.
The differential cross sections for KL0p→KS0p scattering are presented in several momentum intervals between 1 and 10 GeVc. The data are strongly peaked in the forward direction, characteristic of a large s-channel helicity-nonflip scattering amplitude in this reaction, and a distinct break in the differential cross section occurs at |t|=0.3 GeV2. The phase of the forward scattering amplitude, φ, is consistent with being independent of momentum. The average value of the phase, φ=−133.9±4.0∘, corresponds to a Regge trajectory α(0)=0.49±0.05 in agreement with the canonical ρ, ω0 Regge intercept, α(0)∼0.5. However, this result disagrees with the Regge trajectory determined from the energy dependence of the forward cross section, α(0)=0.30±0.03, indicating a breaking of the Regge phase-energy relation. Comparisons of KL0p→KS0p and π−p→π0n scattering data reveal substantial differences in the energy dependence of the differential cross sections. Comparisons to KN charge-exchange data then suggest that direct-channel (absorption) effects may explain the differences in πN and KN channels.
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The polarization parameter for the reaction π−p→π0n has been measured at five incident been momenta between 1.03 and GeV/c. The results are compared with predictions of recent phase-shift analyses.
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Results are reported based on a study of 3114 π−p events at 205 GeV/c in the National Accelerator Laboratory 30-in. bubble chamber. The measured π−p total and elastic cross sections are 24.0 ± 0.5 and 3.0 ± 0.3 mb, respectively. The elastic differential cross section has a slope of 9.0 ± 0.7 GeV−2 for 0.03≤−t≤0.6 GeV2. The average charged-particle multiplicity for the inelastic events is 8.02 ± 0.12.
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