The inclusive jet cross section has been measured in the UA1 experiment at the CERN p p Collider at centre-of-mass energies √ s = 546 GeV and √ s = 630 eV. The cross sections are found to be consistent with QCD predictions, The observed change in the cross section with the centre-of-mass energy √ s is accounted for in terms of x T scaling.
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The multiplicities per event of π ± and K ± are measured separately for e + e - annihilation into c c , b b , and light quark pairs at E cm=29 GeV. The K ± multiplicity is higher for heavy quark events than for light quark events. The π ± multiplicity and the π ± scaled differential cross section at low x = E beam/ E beam are found to be higher for b b events than for other events.
Numerical values requested from authors. Data given separately for (b bbar), (c cbar) and light quark jets.
Measured multiplicities for (b bbar) jets.
Measured multiplicities for (c cbar) jets.
The n̄p total and annihilation cross section have been measured from near N̄N threshold (1880 MeV) to 1940 MeV with RMS resolution ranging from 0.08 MeV (1880 MeV) to 6.7 MeV (1940 MeV). No significant narrow meson structures were seen, with 90% CL upper limits of 40–180 mb-MeV on σΓ for states with width less than our resolution. Combined with increasing unitarity bounds on σ as one approaches threshold, these limits confine widths of possible predicted states below 1900 MeV to less than ∼ 1 MeV.
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The interaction between antiprotons and protons has been studied in the range 1910 to 1990 MeV center-of-mass energy in a drift-chamber experiment at the Brookhaven Alternating Gradient Synchrotron. The total cross section has been determined at eleven different incident momenta, and the elastic cross section between 8 and 30 deg in the laboratory has been measured with an energy resolution of about 5 MeV. The cross section for annihilation into charged mesons has also been measured, with the same resolution. There is no evidence in any of these channels for the existence of a narrow resonance.
Data are for total sample with nuclear physics calculation as described in the paper.
Partial elastic cross sections.
Partial annihilation cross sections.
The first data on the production of D ∗ (2010) are presented as observed in π − -proton interactions at √ s = 27 GeV . It is found that D ∗ (2010) dominates the total charm D-meson production, without a significant non-central component.
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We report on the first search with virtual photon-photon collisions for narrow, neutral resonances with even C parity in the mass range 4.5<W<19 GeV. The data were obtained via the process e+e−→e+e−γ*γ*→e e−+R with both the scattered e+ and e− detected. We find upper limits (95% confidence level) for the partial decay width of a resonance into two photons, ranging from 50 keV at W=4.5 GeV to 10 MeV at W=19 GeV. These limits constrain theoretical models involving neutral composite bosons.
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Data are presented for the exclusive reaction pp → pp π+ π− at\(\sqrt s= 62GeV\) with two leading protons at large Feynman-x and a centrally produced π+;π− system. In this kinematical configuration one expects a substantial contribution from Double Pomeron Exchange, which is a potential source of glueballs. The experiment was performed at the CERN ISR using the Split Field Magnet spectrometer. In the mass range between 1,000 and 1,700 MeV/c2 the invariant mass distribution for the central π+;π− system exhibits a very significant signal for thef0(1270) and no other obvious resonant states.
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The energy distribution of inclusive hadrons produced by 280 GeV muons on hydrogen and deuterium targets are compared. The sum of the scaled energy distributions of the positive and negative hadrons is found to be the same for the two targets. The difference of these distributions is observed to factorise inx andz and thez-dependence is found to be independent of the target type and have a form (1−z)2.1±0.2. The net charge of the hadronic jet is positive at highx even in the case when the scattering takes place on the neutron. These results are in good agreement with the expectations of the Quark Parton Model.
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We report final results on prompt electron production in hadronic events from e+e− annihilations at √s =29 GeV, obtained with the DELCO detector at the SLAC storage ring PEP. We find the semielectronic branching ratios of charm and bottom quarks to be B(c→se+νe)=(11.6−0.9 +1.1)% and B(b→ce−ν¯e)=(14.9−1.9 +2.2)% respectively. These results, from the complete data set, are consistent with an earlier analysis of partial data and indicate hard fragmentation functions for both c and b quarks, with mean values 〈zc〉=0.59±0.04 and 〈zb〉=0.72±0.05. The errors indicated here are a combination of statistical and systematic uncertainties.
Axis error includes +- 0.0/0.0 contribution (NOT GIVEN).
Axis error includes +- 0.0/0.0 contribution (NOT GIVEN).
Axis error includes +- 0.0/0.0 contribution (NOT GIVEN).
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