Professor Brian Foster OBE, FRS

Abstract:

The lifetime of the Ds meson has been measured using the TASSO detector at PETRA and found to be (5.7-2.6 ^+3.6±0.9)×10^-13 s. The method used was to reconstruct fully the decay vertex of the channel Ds→φ{symbol}π^±, φ{symbol}→K⁺K^-. © 1987 Springer-Verlag.

Abstract:

We have measured the process e+e-→e+e-+hadrons, where one of the scattered electrons was detected at large angles, with Q2 ranging from 7 to 70 (VeV/c)2. The photon structure function F2γ(x, Q2) was determined at an average Q2 of 23 (GeV/c)2. The measurements were compared to theoretical predictions of the Quark Parton Model and Quantum Chromodynamics. In both models a hadronic part was added. Within the errors the data are in agreement with the QPM using quark masses of 300 MeV/c2 for the light quarks. The data also agree with a QCD calculation including higher order corrections. A fit yielded a {Mathematical expression} value of 140-65+190 MeV, where the errors include statistical and systematic uncertainties. © 1986 Springer-Verlag.

Abstract:

The reaction e⁺e^-→e⁺e^- A2 (1320) has been observed by detecting the decay A2→π⁺,π^-π⁰. The two-photon width of the A2 has been measured to be G{cyrillic}(A2→γγ)=(0.09±0.27 (stat)±0.16 (syst)) keV. The cross section σ(γγ→π⁺,π^-π⁰ has been determined outside the A2 resonance region. © 1986 Springer-Verlag.

Abstract:

We have determined the D⁰ lifetime from reconstructed vertices of D⁰ mesons produced in e⁺e^- annihilations at an average center of mass energy of 42.2 GeV. From fifteen events the D⁰ lifetime was determined to be (4.3-1.4^+2.0±0.8)×10^-13s. © 1986 Springer-Verlag.

Abstract:

Bose-Einstein correlations between pairs of charged particles produced in e+e- annihilation into hadronic final states have been studied as a function of Q2, the relative momentum squared of the two particles in their centre of mass, and as functions of various pairs of kinematic variables. The observed Bose-Einstein enhancement reveals correlation between the position and time of particle emission, and the space-time structure of the source is shown to differ from that of a pion fireball. While most features of the data are well accounted for in terms of the space-time structure of a simple string model, the correlations are better described by the simple function 1+αe-βQ2. The implications of this result are discussed. The principal features of three particle correlations are explained in terms of the structure of the source inferred from the observed two particle correlations. © 1986 Springer-Verlag.