We have measured the multiplicities of pions produced in the collisions of π mesons with neon nuclei at bombarding momenta of 10.5 and 200 GeV/c. The diffractive production of pions is clearly separable. If one excludes the diffractive part, the pion multiplicity obeys the same Koba-Nielsen-Olesen scaling as found previously for π−−p collisions. This fact would seem to indicate the validity of an energy-flux or collective-variable description of the production process. A surprisingly large number of energetic protons (> 1 GeV/c lab momentum) are found to be produced in π-Ne collisions.
Elastic and diffractive events removed.
None
No description provided.
No description provided.
No description provided.
A structure has been observed at 2220 MeV in the mass spectrum of ηη ′ systems produced by 38GeV/ c and 100 GeV/ c ′ negative pions on protons. The angular distribution of the decay products shows that this structure is presumably a spin J ⩾ 2 meson.
No description provided.
No description provided.
Results are presented from experiment WA7 at the CERN SPS, which has measured the elastic differential cross sections of π ± p, K ± p, p p and pp at incident momen ta of 20, 30 and 50 GeV/ c . The measurements cover the momentum transfer range 0.5 < | t | < 8 (GeV/ c ) 2 , corresponding to c.m. scattering angles between 10° and 50°. The experimental set-up, trigger logic and data analysis are described. The experimental results are compared with existing meson-proton and nucleon-proton data at lower and higher energies covering the medium- and large-| t | region. Some prominent models and their predictions for elastic scattering at WA7 energies and beyond are reviewed, with emphasis on geometrical scaling, factorizing eikonal models, lowest-order QCD and other dynamical exchange-type models. Results for p p two-body annihilation into π − π + and K − K + at 30 and 50 GeV/ c , obtained in parallel with the elastic p p data, are also presented.
No description provided.
No description provided.
No description provided.
The reaction K−p→K¯0π−p has been studied at 100 and 175 GeV/c and the reaction π−p→K0K−p at 50, 100, and 175 GeV/c. Both reactions are dominated by production of resonances, K*(890), K*(1430) and A2(1320), A2(2040), respectively. Production cross sections, t distributions, and decay-angular distributions are studied. Isoscalar natural-parity exchange is dominant. The energy dependence of the K* and A2 resonance production between 10 and 175 GeV/c is well described by a Regge-pole model. Our data on A2 corrects that in an earlier paper.
No description provided.
No description provided.
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.
The reaction π−p→K0K−p has been measured from 50 to 175 GeV/c. The production characteristics of the A2 have been analyzed. We find spin and t dependence similar to lower energies, but the cross section falls rapidly with energy. In a Regge description of π−p→A2−p our data imply a rather small Pomeron-exchange component.
No description provided.
RAW CROSS SECTION WITHIN MASS CUTS.
No description provided.
Energy, charge and strangeness flow inK+p interactions at 32 and 70 GeV/c, and π+p interactions at 32 GeV/c are studied in terms of the angular variable λ=|x|/pT. The data ondQ/dλ anddE/dλ show only a weak indication of scale breaking between 32 and 70 GeV/c. For inclusive “non-diffractive”, inclusive “diffractive” and exclusive “non-diffractive” jets, the fraction of charge in any angular region ΔΩ away from the central region is found to be proportional to the energy fraction in the same interval. The data ondQ/dE versus λ are compatible with some versions of dual-sheet models and agree also with the LUND Monte-Carlo model. The data are also compared with\(v(\bar v)p\) interactions in BEBC. In exclusive channels the average ratiodQ/dS=0.78±0.04 is consistent, in the framework of fragmentation models, with a larger probability for the fragmentation of the\(\bar s\)-valence quark than theu-valence quark in theK+-meson.
CHARGE FLOW IN NONDIFFRACTIVE PROTON-LIKE AND KAON-LIKE JETS.
CHARGE FLOW IN NONDIFFRACTIVE PROTON-LIKE AND KAON-LIKE JETS.
CHARGE FLOW IN NONDIFFRACTIVE PROTON-LIKE AND KAON-LIKE JETS.
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.
Measurements of the differential elastic cross sections for π − p scattering at incident momenta of 20 and 50 GeV c and π + p at 50 GeV c in the momentum transfer range 0.7 < |t|; < 8.0 ( GeV c ) 2 are presented. The data are compared with various models of elastic scattering.
No description provided.
No description provided.
No description provided.
Forum