The properties of the final-state hadronic system in antineutrino-proton charged-current interactions are presented. The events were observed in the Fermilab 15-foot hydrogen bubble chamber. The average energy of the events is ∼30 GeV, but there are some interactions beyond 100 GeV. The mean multiplicity of the charged hadrons varies as 〈nCH〉=(0.06±0.06)+(1.22±0.03)lnW2 for hadronic masses W in the range 1.0
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This paper gives a detailed description of an experiment which studies the interactions of muon-type neutrinos in hydrogen and deuterium. The experiment was performed at the Zero Gradient Synchrotron using the wide-band neutrino beam incident on the Argonne 12-foot bubble chamber filled with hydrogen and deuterium. The neutrino energy spectrum peaks at 0.5 GeV and has a tail extending to 6 GeV. The shape and intensity of the flux is determined using measurements of pion yields from beryllium. The produced pions are focused by one or (for the latter part of the experiment) two magnetic horns. A total of 364000 pictures were taken with a hydrogen filling of the bubble chamber and 903 000 with a deuterium filling. The scanning and other analyses of the events are described. The most abundant reaction occurs off neutrons and is quasi-elastic scattering νd→μ−pps. The separation of these events from background channels is discussed. The total and differential cross sections are analyzed to obtain the axial-vector form factor of the nucleon. Our result, expressed in terms of a dipole form factor, gives an axial-vector mass of 0.95±0.09 GeV. A comparison is made to previous measurements using neutrino beams, and also to determinations based upon threshold pion electroproduction experiments. In addition, the data are used to measure the weak vector form factor and so check the conserved-vector-current hypothesis.
Measured Quasi-Elastic total cross section.
The cross sections for the line-reversed reaction pairs K+n→K0p and K−p→K¯0n, and K+p→K0Δ++ and K−n→K¯0Δ− have been determined with high statistics and good relative normalization at 8.36 and 12.8 GeV/c in a spectrometer experiment at Stanford Linear Accelerator Center. The cross sections for the K+-induced reactions are larger than for the K−, contrary to the expectations of weakly-exchange-degenerate Regge-pole models. The ratio of the reaction cross sections is about the same as at lower energies and shows little change with momentum transfer.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
We report measurements of the electroproduction of ϕ mesons from hydrogen at Q2 values of 0.23, 0.43, and 0.97 GeV2 with |t| varying from 0.125 to 1.3 GeV2 at each Q2 point. The data show no evidence for a Q2 dependence of the slope of the t distribution; the forward cross section falls with increasing Q2 as the square of the ϕ propagator; the decay angular distributions agree with the predictions of s-channel helicity conservation; and the ratio of the longitudinal to the transverse component increases linearly with Q2.
'DATA POINT ONE'.
'DATA POINT TWO'.
'DATA POINT THREE'. POOR STATISTICS - NOT IN PUBLISHED FIGURE.
Dimuon production is studied in 400-GeV proton-nucleus collisions. A strong enhancement is observed at 9.5 GeV mass in a sample of 9000 dimuon events with a mass $m_{\mu^+\mu^-} \to$ 5 GeV.
Two peaks were observed. Mass spectrum was fitted to one and two resonance hypothesis.
We have measured the invariant cross section for inclusive ϕ production in proton-nucleus collisions at 400 GeV/c near Feynman x=0. For transverse momenta in the range between 0.8 and 3.5 GeV/c the ratio of ϕ to π− rises from 1 to 7%. We also report on correlations with particles opposite the ϕ in the center-of-mass system as they relate to the Okubo-Zweig-Iizuka rule.
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The multiplicity distribution of inclusive electron events above 4 GeV cm energy shows two distinct classes of events: two prong no photon and high multiplicity events. If the high multiplicity events are attributed to the semi-leptonic decay of charmed particles the two prong no photon events must come from the weak decay of a different type of particle. The charged K to π ratio was measured for these events. The average number of charged kaons is 0.07 ± 0.06 per two prong event and 0.90 ± 0.18 per multiprong event. Thus the weak current responsible for the low multiplicity events has a small coupling to strange particles.
NUMBER OF CHARGED PARTICLES OBSERVED .EQ. 2.
NUMBER OF CHARGED PARTICLES OBSERVED .GE. 3.
The production of enutral kaons in e + e − annihilation has been measured for c.m. energies between 3.4 GeV and 7.6 GeV. Near 4 GeV the inclusive K S cross section shows an increase and structure similar to total hadron production. Roughly 40–45% of all hadronic final states contain kaons, except at 4.028 GeV and 4.415 GeV, where a significantly larger kaon fraction is observed.
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THIS IS TWICE THE MEASURED KS CROSS SECTION. THE ERRORS ARE STATISTICAL ONLY. THERE IS 15 PCT ABSOLUTE NORMALIZATION ERROR, PLUS POSSIBLY SOME ENERGY DEPENDENT ERROR. THE DATA ARE NOT EQUALLY SPACED IN THE ENERGY INTERVALS.
The reactions K − d→ Σ − p, K − d→ Σ − (1385)p, K − d→ Λ (1405)n and K − d→ Λ (1520)n have been studied at K − momenta between 686 and 844 MeV/ c in an experiment with the 81 cm Saclay bubble chamber at CERN. About 630 000 pictures have been analyzed. Partial and differential cross sections are presented. A one-nucleon-exchange model is used to extract the kaon-nucleon-hyperon coupling constants from these results. For g( K N Σ(1197)), g( K N Σ(1385)) and g( K N Λ(1405)) we find values which are compatible with the SU(3) predictions. The coupling constant g( K N Λ(1520)) obtained by our method agrees with that determined from the partial decay width for Λ(1520)→ K N .
CROSS SECTIONS FROM FITTING WITH BREIT-WIGNER DISTRIBUTIONS AND SMOOTH BACKGROUND.
CROSS SECTION WITH A T-CUT.
CROSS SECTION WITH A T-CUT.
Results are presented on the inclusive reactions p p → K 0 X , p p → Λ X and p p → Λ X at an incident antiproton momentum of 12 GeV/ c in BEBC. The cross sections are studied as functions of the Feynman scaling variable x , the rapidity, the transverse momentum of the V 0 and the missing mass squared. The dependence of the Λ and Λ polarization on x are also studied. Comparisons with proton-proton data at 12 GeV/ c are also made. Finally, events with two detected V 0 are analyzed in order to study correlations arising from the production of two strange neutral particles.
No description provided.
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