We have carried out high-statistics measurements of inclusive π0 and γ-ray spectra from p¯p annihilation at rest. From the monochromatic peaks in the π0 spectra, we derive the yield (or its upper limit) of the reaction p¯p→π0M for M=φ, η’, ω, ρ0, η, and π0. The same quantity was independently obtained from the γ-ray spectra, which included some π0’s that were mistaken as single γ rays due to the limited granularity of the γ detector. Taking the monochromatic peaks in the γ-ray spectra as being due to prompt γ rays, we also derive the upper limit for p¯p→γM.
No description provided.
No description provided.
The KS0KS0π0 system has been studied in the exclusive reaction π−p→KS0KS0π0n at 21.4 GeV/c. Evidence for the production of the f1(1285) and the η(1460) is presented. The η(1460) is produced away from minimum momentum transfer in the presence of nonresonant K*K (S-wave) production and phase-space background. The observed mass, width, and decay properties of the η(1460) are consistent with those attributed to the ι(1460) observed in radiative Jψ decay.
No description provided.
We have measured absolute differential cross sections and analyzing powers for neutron-proton elastic scattering for momentum transfer 0.01 < | t |< 0.08 (GeV/ c ) 2 at several energies between 378 and 1135 MeV. The ionization chamber IKAR filled with methane was used as both a gas target and recoil detector. For the analyzing-power measurements the scattered neutron was detected in scintillation counters in coincidence with the recoil proton detected in IKAR. Special care was taken to ensure a precise absolute normalization of the cross sections, with overall systematic uncertainties of 4–7%.
TOTAL SYSTEMATIC UNCERTAINTIES IN D(SIG)/D(T)=6.4 PCT.
TOTAL SYSTEMATIC UNCERTAINTIES IN D(SIG)/D(T)=5.4 PCT.
TOTAL SYSTEMATIC UNCERTAINTIES IN D(SIG)/D(T)=6.5 PCT.
Inelastic p - 3 He events at 192.8 MeV/ c are detected with a self-shunted streamer chamber. The measured reaction cross section is 392±23.8mb. This result is briefly discussed and compared with other reaction cross sections for low-energy p with light nuclei.
Charged prong multiplicity distribution in annihilation events.
Measured inelastic cross section.
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No description provided.
No description provided.
We present data on two-particle pseudorapidity and multiplicity correlations of charged particles for non single-diffractive\(p\bar p - collisions\) at c.m. energies of 200, 546 and 900 GeV. Pseudorapidity correlations interpreted in terms of a cluster model, which has been motivated by this and other experiments, require on average about two charged particles per cluster. The decay width of the clusters in pseudorapidity is approximately independent of multiplicity and of c.m. energy. The investigations of correlations in terms of pseudorapidity gaps confirm the picture of cluster production. The strength of forward-backward multiplicity correlations increases linearly with ins and depends strongly on position and size of the pseudorapidity gap separating the forward and backward interval. All our correlation studies can be understood in terms of a cluster model in which clusters contain on average about two charged particles, i.e. are of similar magnitude to earlier estimates from the ISR.
Correlation strength for different choices of pseudorapidity intervals.
Correlation strength as a function of the central gap size for the symmetric data.
Correlation strength as a function of the centre of the separating gap for a gap size of 2.
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No description provided.
No description provided.
Values of the spin-rotation parameter, β, are measured in the reaction π + p → K + Σ + at incident pion momenta of 1.69 and 1.88 GeV/ c .
No description provided.
No description provided.
A search for multihadronic events produced with two energetic leptons has been performed at PETRA using 130 pb −1 accumulated by the CELLO detector at 35 GeV ⩽ √ s ⩽46.8 GeV. Three μ + μ − , eleven e + e − and three eμ events were observed. The mesured yields an dthe event characteristics are in good agreement with the expectation for the α 4 QED processes e + e − → ℓ + ℓ − q q and from semileptonic decays of pairs of heavy quarks.
No description provided.
The final states K S 0 K S 0 π + π − and K S 0 K ∓ π 0 π ± , produced in two-photon reactions, have been studied using the ARGUS detector at the e + e − storage ring DORIS II at DESY. The reaction γγ→ K ∗+ K ∗− has been observed for the first time. Its cross section is about eight times larger than that for γγ→ K ∗0 K ∗0 , but it has a similar W γγ dependence.
No description provided.
Topological cross section.
Topological cross section.