Professor Brian Foster OBE, FRS

Abstract:

We have studied the correlations between charged particles produced in e+e- annihilations into hadrons at c.m. energies between 29 and 37 GeV. We have analysed the correlations between the charged multiplicities of the jets and the two particle rapidity and charge correlations. No evidence for correlations between the multiplicities of the two jets is found. Two particle short range rapidity and charge correlations are observed, indicating that particles cluster in rapidity and that their charges compensate locally. An extensive study of these correlation effects by QCD Monte Carlo calculations was performed. Evidence for charge correlations due to Bose-Einstein statistics is also observed. © 1985 Springer-Verlag.

Abstract:

An analysis of the production of KS⁰KS⁰ and K^±Ks⁰π^∓ by two quasi-real photons is presented. The cross section for γγ→K⁰ {Mathematical expression}, which is given for the γγ invariant mass range from K {Mathematical expression} threshold to 2.5 GeV, is dominated by the f′(1525) resonance and an enhancement near the K {Mathematical expression} threshold. Upper limits on the product of the two-photon width times the branching ratio into K {Mathematical expression} pairs are given for Θ(1700), h(2030), and ξ(2220). For exclusive two-photon production of K^±Ks⁰π^∓ no significant signal was observed. Upper limits are given on the cross section of γγ→K⁺ {Mathematical expression}π^- or K^-K⁰π⁺ between 1.4 and 3.2 GeV and on the product of the γγ width times the branching ratio into the K {Mathematical expression}π final states for the ηc(2980) and the ι(1440), yielding Γ(γγ)→i(1440))·BR(i(1440)→K {Mathematical expression}π<2.2 keV at 95% C.L. © 1985 Springer-Verlag.

Abstract:

We have measured the cross sections for e+e- → e+e-, e+e- → μ+μ-, e+e- → γγ and e+e- → hadrons in an energy scan at center of mass energies between 39.79 and 46.72 GeV in 30 MeV steps. New spinless bosons, whose existence has been postulated as a possible means to explain the anomalously large radiative width of the Z0 found at the CERN SPS pp collider, are ruled out in the scan region. The data are used to set limits on the couplings to lepton, photon and quark pairs of bosons with masses above 46.72 GeV. © 1985.

Abstract:

Three-jet events produced by e+e- annihilation into hadrons at 34.6 GeV c.m. energy were studied by comparing them with 2nd order QCD and two different models of fragmentation. The distribution of low energy particles in the 3-jet plane is found to be better described by the LUND color string model than by the independent jet model. The opposite is true for more energetic particles flowing between the 3 jets. The average transverse momenta in jets can be described with values of σq between 350 and 500 MeV/c for the gluon jet. © 1985 Springer-Verlag.

Abstract:

We have observed τ pair production at average CM energies of 13.9, 22.3, 34.5 and 43.1 GeV. The cross-sections are consistent with QED, the cut off parameters being Λ+>161 GeV and Λ-169 GeV (95% CL). The topological branching fraction of the τ to 1 charged particle, B1, is 0.847±0.011 (stat)-0.013+0.016(syst) and no decays to 5 charged particles were observed resulting in B5<0.007 (95% CL). Within the 3 charged track final state B(τ-→π-π+π- v)/(B(τ-→π- π+π- v)+B(τ-→π-π+π -π0v))=0.37-0.20+0.35 © 1985 Springer-Verlag.