The neutron-proton elastic differential cross section has been measured for incident momenta between 10 and 70 GeV/c and for values of the momentum transfer squared between 0.1 and 2.8 (GeV/c) 2 . The forward peak and the break at about ∣ t ∣ = 1 (GeV/ c ) 2 are very similar to corresponding pp data.
No description provided.
No description provided.
The differential cross sections for neutron-proton elastic charge-exchange scattering have been measured with a two-arm technique for incident neutron momenta between 22 and 65 GeV/ c and for values of the momentum transfer squared between 0.002 and 0.8 (GeV/ c ) 2 . The sharp forward peak observed previously at lower energies is also present at momenta up to 65 GeV/ c ; however the s dependence of the cross section is slowing down.
No description provided.
No description provided.
No description provided.
The differential cross sections for elastic π − p, K − p , p p and π + p, pp scattering at 39 and 44.5 GeV/ c , respectively, have been measured in the interval of momentum transfer squared 0.15 ≤ ovbt | ≤ 2 (GeV/ c ) 2 .
No description provided.
No description provided.
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.
π−p→π0n differential cross-sections have been measured in the region of small 4-momentum transfer at 40 GeV/c incident momentum. The experiment performed at the IHEP 70 GeV accelerator makes use of a hodoscope γ-spectrometer. Thet- dependence of the cross-section points to a dominance of the spin-flip amplitude.
No description provided.
The mass and momentum transfer spectra of the charged K K system produced in the reaction π ± p→K s 0 K ± p are analyzed. The data have been collected at the CERN SPS with the Geneva-Lausanne two-arm, non-magnetic spectrometer at 30 and 50 GeV/ c incident momenta. The general features of the reactions at these energies and the results of partial-wave analyses of the two kaon system are presented. The channel is dominated by the diffractive production of even spin resonances. The spin 4 recurrence of the A 2 (1320) is clearly observed at 2040 MeV ( Γ =380 MeV. A new resonance is observed with a mass M =2450MeV and a width Γ =400 MeV; the quantum numbers of this state are found to be I G ( J PC )=1 −(6 ++ ) . The analysis also shows the decay of the decay of the meson ϱ′(1600) through the K K channel at both energies. The production amplitudes are determined both as a function of the K K effective mass and of the momentum transfer. Isoscalar natural parity exchange is dominant. The energy dependence between 10 and 50 GeV/ c is shown to be well described by a Regge pole model based on the f-dominated pomeron hypothesis. We compare the production mechanisms of the 2 + resonances A 2 (1320) and K ∗ (1430). Finally, we estimate the K K branching ratios of the spin 4 A 2 (2040) and spin 6 A 2 (2450) resonances.
No description provided.
D(SIG)/DT FOR 50 GEV IN RESONANCE REGIONS.
No description provided.
The reactions K ± p→K s 0 π ± p are studied at 30 and 50 GeV/ c . Data for these reactions were obtained using the Geneva-Lausanne spectrometer whose main characteristics are: (i) large forward acceptance; (ii) high-resolution time-of-flight for recoil proton momentum measurement; (iii) high data-taking rate and on-line pattern recognition. The K ∗ (1 − ), K ∗ (2 + ), K ∗ (3 − ) and K ∗ (4 + ) resonance parameters and production cross sections are determined. The K π production amplitudes are calculated both as a function of the K π mass and of the momentum transfer. Isoscalar natural parity exchange (NPE) is dominant. The NPE amplitudes are decomposed into pomeron- f-, ω-exchange contributions, and their energy dependence between 10 and 50 GeV/ c is shown to be well-described by a Regge pole model based on the f-dominated pomeron hypothesis.
CORRECTED TO INCLUDE BW TAILS AND THE FRACTION OF EVENTS OUTSIDE THE T-ACCEPTANCE OF THE SPECTROMETER.
FITS OF THE FORM -A*TP*EXP(BTP) ARE MADE BY THE AUTHORS AND THE VALUES OF A AND B ARE GIVEN HERE. MASS REGIONS OF THE FIT ARE:-. K*(890) 0.84 < M <0.94 GEV. K*(1430) 1.36 < M <1.5 GEV. K*(1780) 1.68 < M <1.88 GEV.
FITS OF FORM -A*TP*EXP(BTP) ARE MADE BY THE AUTHORS AND THE VALUES OF A AND B ARE GIVEN HERE. MASS REGIONS OF THE FIT ARE:-. K*(890) 0.84 < M <0.94 GEV. K*(1430) 1.36 < M <1.5 GEV. K*(1780) 1.68 < M <1.88 GEV.
We present results on photoproduction of ϱ 0 and ω in the reactions γ p→ π + π − p and γ p→ π + π − π 0 p by tagged photons in the energy ranges 20 to 70 GeV and 20 to 45 GeV, respectively. The production of the ϱ 0 shows dominantly the characteristics of a diffractive process with respect to the E γ and t dependence of the cross section and the spin density matrix. The ϱ 0 photoproduction yields on average over the photon energy range a total cross section of σ ( γ p→ ϱ 0 p) = 9.4±0.1 μ b with an additional systematic error of ±1 μ b, and average slope parameters of the t distribution d σ /d t ≈exp(− b | t | + ct 2 ), of b =9.1±0.1 GeV −2 and c = 3.1 ±±0.2 GeV −4 . The shape of the ϱ 0 peak in the π + π − invariant spectra shows a skewing similar to that observed at lower energies. The photoproduction of ω is also consistent with a diffractive process and has a cross section of σ ( γ p→ ω p) = 1.2± 0.1 μ b with an additional systematic error of ±0.2 μ b. The average slope parameters of the t distribution are b =8.3 ± 1.3 GeV −2 and c = 3.4±2.6 GeV −4 .
FITS USING THE SODING PARAMETERIZATION.
FITS USING THE ROSS-STODOLSKY PARAMETERIZATION.
No description provided.
Differential cross sections for π − p and pp elastic scattering have been measured at incident momenta ranging from 30 to 345 GeV and in the t range 0.002 (GeV/ c ) 2 ⩽ | t | ⩽ 0.04 (GeV/ c ) 2 . From the analysis of the data, the ratio ϱ ( t = 0) of the real to the imaginary parts of the forward scattering amplitude was determined together with the logarithmic slope b of the diffraction cone.
No description provided.
No description provided.
No description provided.
Results on photoproduction of π + π − π 0 in the photon energy range 20–70 GeV are presented. For the ω meson, the production cross-section is found to be 1010±15 (statistical)±290 (systematic) nb and is constant over the incident photon energy range. Spin-density matrix elements are evaluated for ω meson production. The φ meson is observed with a total photoproduction cross section (corrected for branching ratio to π + π − π 0 ) of 610±35±170 nb. A third resonance, at 1.67 GeV, is seen in the mass spectrum and its interpretation is discussed. The production of a broad π + π − π 0 continuum, mainly via ϱπ, and peaking at 1.2 GeV, contributes with a cross section of about 2.5 ωb. The spin-parity content is analysed by the moments of the π + π − π 0 decay angular distribution in the helicity frame and by maximum likelihood fits to the π + π − π 0 Dalitz plot. It is found that production of J P = 1 − states accounts for less than half of the total mass spectrum above 900 MeV. There is a broad enhancement in the 1 + wave around 1.15 GeV indicating photoproduction of the H(1190) meson.
No description provided.
EXPONENTIAL FITS TO D(SIG)/DT IN OMEGA MASS REGION.
EXPONENTIAL FITS TO D(SIG)/DT OVER FULL ENERGY FOR THREE MASS REGIONS CORRESPONDING TO OMEGA, PHI AND OMEGA*.
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