Evidence is presented for inclusive photoproduction of F ± mesons in three decay modes, ηπ ± , ηπ ± π + π − and ηπ ± π + π + π − π − . The average mass of the F ± is found to be 2.020±0.010 GeV.
No description provided.
The polarization and Q2 dependence of muoproduced ψ→μ+μ− have been analyzed in a magnetized-steel calorimeter at Fermilab. The reaction γVN→ψN is found to be helicity conserving. Even after allowance for possible Q2 dependence of the decay angular distribution, the ψ muoproduction cross section falls more steeply in Q2 than predicted by ψ dominance.
EFFECTIVE CROSS SECTION IN ARBITRARY UNITS.
EFFECTIVE CROSS SECTION IN ARBITRARY UNITS.
EFFECTIVE CROSS SECTION IN ARBITRARY UNITS.
Data are presented for the reaction ep → ep π 0 at a nominal momentum transfer squared of 1.0 (GeV/ c ) 2 . The data were obtained using an extracted electron beam from NINA and two magnetic spectrometers for coincidence detection of the electron and proton. Differential cross sections have been measured for isobar masses in the range 1.19–1.73 GeV/ c 2 .
No description provided.
No description provided.
No description provided.
Additional systematic uncertainty 25% not included.
We present differential cross sections andΔ++ spin density matrix elements for the photoproduction processγp→π−Δ++ and differential cross sections for the processγp→π+Δ0. The incident photon energy dependence is studied and a comparison is made with previous experiments and with the predictions of a theoretical model.
DIFFERENTIAL CROSS SECTION AVERAGED OVER WHOLE ENERGY RANGE.
DIFFERENTIAL CROSS SECTION AVERAGED OVER WHOLE ENERGY RANGE.
DIFFERENTIAL CROSS SECTION FOR DIFFERENT ENERGY RANGES.
A tagged photon beam (2.8<Eγ<4.8 GeV) and multiparticle spectrometer have been used to study the photoproduction in hydrogen ofK+Λ(1520). Precise values for the mass and width of the Λ(1520) are given. The total cross-section is found to fall with increasing photon energy like (6.5±0.7)Eγ−(2.1±0.2) μb. The differential cross sectiondσ/dt indicates peripheral forward production and exhibits no evidence for shrinkage when compared with higher energy data. The Λ(1520) spin density matrix shows thatK exchange alone cannot account for the production mechanism. The reaction is found to resemble the process γp→K+ Λ(1115) in all measurable respects.
FITTED CROSS SECTION ENERGY DEPENDENCE IS SIG = (6.7 +- 0.7 MUB*GEV**2) * P**(-2.1 +- 0.2), INCLUDING HIGHER ENERGY DATA.
EXPONENTIAL SLOPE IS 6.1 +- 2.0 GEV**-2 FOR -T = 0.2 TO 0.7 GEV**2.
No description provided.
The reaction γ p→K + K − p has been investigated with photons in the energy range of 20< E γ <36 GeV and with K + K − pairs in the mass range of M K + K − <2.0 GeV. The production of the φ(1019) contributes with a cross section σ ( γ p → φ p) × BR( φ →K + K − ) = 240±6 nb with an additional systematic error of ±20 nb. In the higher mass range of 1.05< M K + K − <2.0 GeV the production of K + K − pairs yields a cross section σ ( γ p→K + K − p) = 160±8 nb with an additional systematic error of +40 −30 nb.
No description provided.
K+ K- PRODUCTION ABOVE PHI MASS.
No description provided.
A dipion enhancement of mass 1.59 GeV and width 0.23 GeV is observed in the channel γp→π + π − p. The spin-parity of the enhancement is consistent with being 1 − .
No description provided.
Virtual photoproduction of J/ ψ mesons has been measured for 280 GeV muon iron interactions in an iron/scintillator calorimeter target. The J/ψ's were identified by their decay into muon pairs. 315 events were observed, about half of which were elastic. The t , Q 2 and v distributions of these elastic events are presented. The v dependence is measured between 40 and 180 Mev and compared with lower energy photoproduction results. The Q 2 dependence is compared with the predictions of the vector dominance model.
TPRIME DISTRIBUTION OF ELASTIC J/PSI EVENTS FOR ALL Q2 AND NU WITH 280 GEV MUON BEAM.
NORMALIZED Q**2 DISTRIBUTION OF ELASTIC J/PSI EVENTS FOR ALL NU AND T WITH 280 GEV MUON BEAM.
EXTRAPOLATION OF Q**2 AND T DEPENDENCE TO CALCULATE D(SIG)/DT AT Q**2=0 AND T=0 FOR ELASTIC J/PSI PHOTOPRODUCTION PER NUCLEON.
We present the first data on photon-photon annihilation into hadrons for CM energies > 1 GeV obtained with the detector PLUTO at the e + e − storage ring PETRA. Cross sections are extracted using an inelastic eγ scattering formalism. The results are compared to expectations from Regge-like models.
DEPENDENCE OF CROSS SECTION FOR ELECTRON-PHOTON SCATTERING (ANALOGOUS TO HAND'S FORMULA) ON VISIBLE HADRONIC ENERGY, CALCULATED BY TAKING PION MASSES FOR ALL CHARGED PARTICLES.
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