The production of thef0 in two photon collisions, with the subsequent decayf0→π+π− has been observed in the CELLO detector at PETRA. Thef0 peak was found to lie on a dipion continuum and to be shifted downwards in mass by ≃50 MeV/c2. The ππ mass spectrum from 0.8 to 1.5 GeV/c2 was well fitted by the model of Mennessier using only a unitarised Born amplitude and helicity 2f0 amplitude. The previously observed mass shift and distortion of thef0 peak are explained by strong interference between the Born andf0 amplitudes. The only free parameter in the fit of the data to the model is the radiative widthΓγγ(f0). It was found that:Γγγ(f0)=2.5±0.1±0.5 keV where the first (second) quoted errors are statistical (systematic).
Data read from graph.
Data read from graph.
The inclusive production ofKs0, Λ and\(\bar \Lambda \) particles is investigated in 70 GeV/c\(\bar pp\) interactions in an experiment performed at CERN using BEBC equipped with a TST. Differential cross-sections are studied and compared with corresponding data at surrounding energies. Differences withpp data obtained at the same energy allow an estimate of theKs0, production cross-section in annihilation processes. Evidence is also given for central\(\Lambda \bar \Lambda \) production.
No description provided.
We have studied at CM energies of 14, 22 and 30–36.7 GeV e + e − annihilation events in which the hadronic final state contains both a proton and an antiproton in the momentum range 1.0 < p < GeV/ c . We find that such pairs are produced predominantly in the same jet and conclude that baryon-antibaryon production is dominated by a mechanism involving local compensation of baryon number.
BACKGROUND SUBTRACTED DATA.
BACKGROUND SUBTRACTED DATA.
New data are presented on the charged multiplicity distribution for non single-diffractive events produced in pp̄ interactions at a CM energy s = 540 GeV . The distribution in the full pseudorapidity range is compared with data from the ISR. Using the scaling variable z = n 〈n〉 a change of shape is observed. The effect is manifested as an increase from 2% to 6% in the proportion of high multiplicity ( z > 2) events. For the central pseudorapidity range, | η | ⪅ 1.5, scaling is approximately valid up to s = 540 GeV .
THE SCALING VARIABLE Z IS N/MEAN(N). THE ERRORS ARE HIGHLY CORRELATED AND ARE BASED ON THE SQUARE ROOT OF THE NUMBER OF EVENTS IN THE BIN. IN THE CASE OF MULTIPLICITIES 2,4, AND 6, ADDITIONAL SYSTEMATIC ERRORS HAVE BEEN INCLUDED. ABOVE MULTIPLICITY 96 BINS HAVE BEEN COMBINED - THE VALUE IN THE TABLE IS THE AVERAGE OVER THE RANGE - NOT THE SUM. NOTE ALSO THAT IN FIG. 1 THE "Y-VALUE" IS MULTIPLIED BY THE MEAN MULTIPLICITY (29.1).
CHARGED MULTIPLICITY (NON-CORRECTED) FOR EVENTS WHICH HAVE AT LEAST ONE TRACK WITH ABS(ETARAP) <1.5.
CHARGED MULTIPLICITY (NON CORRECTED) FOR EVENTS WHICH HAVE AT LEAST ONE TRACK WITH ABS(ETARAP) <1.3.
The parity violation induced by weak neutral currents is measured in a ΔF =1 hyperfine component of the 6S–7S transition of the Cs atom. The measured value ( Im E PV 1 β ) = −1.78 ± 0.26 (statistical rms deviation) ±0.12 (systematic uncertainty) mV/cm, agrees with our previous measurement in a ΔF =0 component, and constitutes an important cross-check. Our result excludes a parity violation induced by a purely axial hadronic neutral current.
(7s)2S1/2:F=3 --> (6s)2S1/2:F=4 transition.
We have measured the p p differential elastic cross section at 8 momenta from 353 to 578 MeV/ c , determining, for each momentum, the ratio ρ of the real to imaginary parts of the elastic forward amplitude, the slope b of the elastic cross section and the total p p cross section σ. Our results are compared with previous experimental results and with theoretical predictions.
No description provided.
No description provided.
Numerical values supplied by M. Cresti.
We present our final data on the production of the baryons p, Λ, Λ , Σ 0 , Σ 0 , Σ − , Σ + , Ω + , and of the baryon resonances Δ ++ (1232), Σ ∗± (1385), Σ ∗± (1385) in K + p interactions at 70 GeV/ c . Results are given on total and semi-inclusive cross sections, transverse momentum distributions and Feynman- x spectra. The data are compared with measurements at 32 GeV/ c and other energies. The predictions of the LUND fragmentation model for low- p T hadron-hadron collisions are examined and found to offer a reasonably successful description of the data.
No description provided.
No description provided.
No description provided.
We have obtained a sample of 20 465 (2201) events in the channel pp→ ( Λ 0 K + )p at 50 (30) GeV/ c incident momentum with Geneva-Lausanne spectrometer at the CERN SPS. In this analysis we investigate: 1. (i) the production of N ∗ (I = 1 2 ) states in the mass region 1.6 ⩽ M ( Λ 0 K + ) ⩽ 2.6 GeV and momentum transfer 0.06 ⩽ | t | 1.0 (GeV/ c ) 2 , by studing the amplitudes and phases from a moment analysis of the decay angular distribution; 2. (ii) the contribution of the K-exchange Deck model for M ( Λ 0 K + < 2.22 GeV; 3. (iii) the double Regge exchange phenomenology for s Λ 0 K + > 5 GeV 2 and s Λ 0 K + p > 5 GeV 2 .
No description provided.
No description provided.
No description provided.
Measurements are reported of p̄p total cross sections from 388 to 599 MeV/ c in small momentum steps. Statistical errors are typically ±0.4%and the normalisation uncertainty is ±0.7%. There is no evidence for the “S-meson”.
DATA TAKEN WITH 8.33 CM LH2 TARGET.
DATA TAKEN WITH 1.17 CM LH2 TARGET.
The total cross section difference Δα L (pp) for proton-proton scattering with beam and target polarized longitudinally parallel and antiparallel, respectively, has been measured using the polarized proton beam from SATURNE II and a frozen spin polarized proton target. The beam polarization was reversed from pulse to pulse, and at each energy Δα L was measured for both signs of target polarization. The data below 800 MeV confirm the previously observed structures. The cross section difference is found to change by 8.0 ± 0.5 mb between 520 MeV and 760 MeV. At the higher energies the results show no indication for similar structures or for a change of the sign of Δα L .
ERRORS INCLUDE UNCERTAINTY IN THE BEAM POLARIZATION.
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