We report on the analysis of inclusive neutral current events produced in neutrino and antineutrino narrow band beams. We find for incident neutrino energies in the range 12–200 GeV and for hadron energies above 12 GeV a neutral to charged current cross-section ratio of R v = 0.293 ± 0.010 for incident neutrinos, and R v = 0.35 ± 0.03 for antineutrinos. These ratios are consistent with the Weinberg-Salam model, with sin 2 θ w = 0.24 ± 0.02.
No description provided.
No description provided.
The charged-current cross sections for neutrinos and antineutrinos on nucleons in the energy range 20–200 GeV are given. Taken in conjunction with the previous Gargamelle results, they show that σ E is almost constant with energy for antineutrinos, and falls with energy for neutrinos. The value of 〈q 2 〉 E decreases with energy for both neutrinos and antineutrinos, and these deviations from exact Bjorken scaling are consistent with those observed in electron and muon inelastic scattering. We find no evidence for new heavy quark states with right-handed coupling.
Measured charged current total cross section.
Measured charged current total cross section.
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No description provided.
No description provided.
No description provided.
We measured 30 000 wide-angle electron-positron pairs from the reaction γ+p→p+e++e− in the invariant-mass region 500≤m≤1060 MeV. The photoproduction amplitudes of the ρ, ω and ϕ mesons were measured to deviate from being pure imaginary by 37.5°−3.1°+2.8°, 29.6°−12.9°+15.5°, 3.4°−4.2°+5.3°,respectively.
DEVIATION OF VECTOR MESON PHOTOPRODUCTION PHASES FROM PURE IMAGINARY.
New results on a high statistics measurement of pion-nucleon charge exchange scattering at 40 GeV/ c , extending in momentum transfer up to − t = 1.8 (GeV/ c ) 2 , are reported and compared with an optical impact parameter model, together with previous data for the reaction π − p → ηn at the same energy. The imaginary part of the pole trajectory b 0 ( s ) is determined from the slope of the tangent to the maxima of (−t) 1 2 d σ d t . The linear increase of Im b 0 ( s ) with log s , which has been observed at low energies, continues up to 40 GeV/ c .
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AT SMALL -T, THE BINNING TENDS TO SMEAR OUT THE FORWARD DIP.
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THE AVERAGE PHASE IS -130.9 +- 2.7 DEG (NO EXPLICIT MOMENTUM DEPENDENCE). USING ABS(ETA+-) = 2.3*10**-3.
REGENERATION AMPLITUDE ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
CROSS SECTION DIFFERENCES ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
None
No description provided.
No description provided.
No description provided.
We report measurements of the polarization parameters in π+p and π−p elastic scattering at an incident momentum of 100 GeV/c. The results cover the range 0.18<~−t<~1.4 GeV2 and are in agreement with current Regge-model predictions.
No description provided.
No description provided.
No description provided.
Proton-proton elastic scattering has been measured in the region 4.9<|t|<12.1 GeV2 at a beam momentum of 201 GeV/c. If the form exp(At) is fitted to the data, the exponent A gradually changes from 1.5 to 0.9 GeV−2 over our t range. The data are consistent with the form exp(−6.6p⊥). A comparison with intersecting storage ring results shows that in this kinematical region the slopes are about the same, but dσdt at fixed t is still dropping with energy.
7904 ELASTIC EVENTS.
1030 ELASTIC EVENTS.
We report on a study of 15-GeV/c π+p interactions of all topologies using the SLAC 82-in. hydrogen bubble chamber. A description is given of the automatic pattern-recognition techniques used to measure the events. Cross sections are given for meson-resonance production in all topologies. Evidence is presented for a new resonance decaying to five pions. A measurement is made of the branching ratios of the g meson. A study is made of low-mass enhancements in the diffractively produced ρπ, fπ, and gπ channels, and a search is made for nondiffractive production of the A1 meson.
TOPOLOGICAL CROSS SECTIONS.
FITTED EVENTS CROSS SECTIONS.
RESONANCE PRODUCTION CROSS SECTIONS.