The polarized target asymmetry for γ n→ π − p was measured over the second resonance region from 0.55 to 0.9 GeV at pion c.m. angles between 60° and 120°. A double-arm spectrometer was used with a deuterated butanol target to detect both the pion and the proton, thus considerably improving the data quality. Including the new data in the amplitude analysis, the radiative decay widths of three resonances were determined more accurately than before. The results are compared with various quark models.
PHOTON ENERGY IS IN THE NEUTRON REST FRAME.
PHOTON ENERGY IS IN THE NEUTRON REST FRAME.
PHOTON ENERGY IS IN THE NEUTRON REST FRAME.
The processes e + e − → e + e − and μ + μ − have been studied at PETRA using the JADE detector. The data, which were collected at s -values of up to 1300 GeV 2 have been analysed in terms of an electro-weak extension of QED to obtain values for the weak vector and axial vector couplings in the lepton sector. The values obtained agree with the predictions of the standard Salam-Weinberg model and the data are further analysed in terms of this model to obtain the limits 0.10 < sin 2 ϑ w < 0.40 (68% CL). The mass of the neutral weak gauge boson is deduced to be greater than 51 GeV/ c 2 .
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
A tagged photon beam and multiparticle spectrometer have been used to measure the backward photoproduction process γp → Δ ++ π − . The energy dependence of the production cross section between 2.8 and 4.8 GeV is studied and found to exhibit shrinkage in excess of that expected for Δ σ dominance. An interpretation of the production mechanism in terms of an incoherent mixture of Δ σ exchange and a “hard scattering” contribution is presented.
No description provided.
The longitudinal momentum spectra of mesons produced in the projectile fragmentation region ofK−p interactions at 110 GeV/c, measured in a bubble chamber experiment, are compared to two fragmentation models related to hadron production by incident leptons. The models give a qualitative description of the data. However, it is found that the mesons having a valence quark in common with the projectile tend to have higher momenta than predicted.
No description provided.
J/ ψ production at 40 GeV/ c by π ± , K ± , p and p incident on hydrogen has been studied and results compared with those obtained on tungsten in the same experiment. On hydrogen, J/ψ cross-section ratios relative to π − have been measured to be (for x F > 0) σ(π − ) : σ(π + ) : σ( p ) : σ( p ) = 1 : (0.78 ± 0.09) : (0.83 ± 0.35) : (0.07 ± 0.04) . The suppression of the proton induced cross sections shows the importance of calence quark-antiquark fusiin J/ψ production at this energy (i.e. M J 2 / ψ / s =0.13).
ERRORS ONLY STAT.
ERRORS ONLY STAT.
No description provided.
The Σ − p and Σ − d total cross sections have been measured to a statistical accuracy of ±1% and ±0.5%, respectively, at five momenta from 74.5 to 136.9 GeV/ c , using the hyperon beam at the CERN SPS. The Ξ − p and Ξ − d total cross sections have also been measured to the same statistical accuracy at 101.5 and 133.8 GeV/ c . The systematic uncertainty at each momentum is estimated to be of the order of ±0.5%. The hyperon-nucleon cross sections are shown to be rising with energy, and the data are compared with various phenomenological models.
Axis error includes +- 0.10/0.10 contribution (FOR DEUT TARGET. ADDED TO STAT. ERROR IN QUADRATURESAME AS ABOVE). Axis error includes +- 0.15/0.15 contribution (FOR PROTON TARGET. ADDED TO STAT. ERROR IN QUADRATURE.UNCERTAINTY OF EXTRAPOLATION OVER T).
No description provided.
The resonance parameters of the ϒ′(10.01) were measured using the LENA detector at the DORIS e + e − storage ring. We obtained a mass of M ( ϒ ′) = (10 013.6 ± 1.2 ± 10.0) MeV and an electronic width of Γ ee ( ϒ ′) = (0.53 ± 0.07 −0.05 +0.09 keV. The upper limit set to the μ-pair branching ratio is 3.8% which implies a lower limit on the total ϒ′ width of 14 keV. Together with out previous measurement of the ϒ parameters we obtain a mass difference M(ϒ′) − M(ϒ) = (552.0 ± 1.3 ± 10.0) MeV and Γ ee (ϒ′) Γ ee (ϒ) = 0.43 ± 0.07 −0.00 +0.05 .
HADRONIC CROSS SECTION IN REGION OF UPSI(10020)0.
Proton-proton elastic scattering using 201- and 400-GeV/c extracted beams at Fermilab has been measured in the region 4.9<−t<14.4 GeV2. Contrary to predictions of diffraction models, there is no sign of a second dip or "break," and the slope A in the fit exp(At) is smaller than predicted. It drops from 1.5 to 0.8 GeV−2 over our t range. The shape of the t distribution can be fitted by the power law dσdt∝t−8.4 which is close to a quantum-chromodynamics (QCD) prediction of t−8. At fixed t the 201-GeV/c cross sections are about 2.3 times those at 400 GeV/c which is compatible with the QCD and constituent-interchange-model prediction that dσdt∝s−10 at fixed ts.
LOW T.
HIGH T.
LOW T.
This paper presents the final results on charged-current neutrino and antineutrino interactions with nuclei from experiment E-310 at Fermi National Accelerator Laboratory. The data sample, consisting of 21 578 neutrino-induced and 7358 antineutrino-induced events within the fiducial region in the energy range 20<E<325 GeV, is exhibited first to demonstrate the basic properties and kinematic regions represented. The dependence of the nucleon structure functions on the dimensionless variable x and on neutrino energy is then described. Lastly, the variations of the structure functions with x and Q2 are presented. The emphasis throughout has been to understand the effects on the final results of uncertainties in the systematic corrections required by the data. Comparisons with the results of other neutrino experiments are made.
VALUES OF Q2 ARE .36,1.07,2.13,3.56,4.98,6.40,7.82,9.24.
VALUES OF Q2 ARE .70,2.11,4.22,7.04,9.86,12.67,15.49,18.30.
VALUES OF Q2 ARE 1.16,3.48,6.97,11.61,16.26,20.90,25.55,30.19.
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