Philip Burrows

Abstract:

The production of strange baryons in e+e- annihilation has been studied at centre of mass energies of 34.8 GeV and 42.1 GeV, using the TASSO detector at DESY. Inclusive cross-sections have been obtained for Λ0 and Ξ- production and an upper limit has been placed upon the production rate of Σ*±(1385). We measure the Λ0 multiplicity per event to be {Mathematical expression} and {Mathematical expression} at {Mathematical expression} and 42.1 GeV respectively. The Ξ- multiplicity per event is found to be {Mathematical expression} at {Mathematical expression}. An investigation has been made of the extent to which Λ0 are produced in pairs. The Λ0 cross-section has been studied as a function of event sphericity. © 1989 Springer-Verlag.

Abstract:

We present a simple dynamical model of baryon production which predicts the form of baryon fragmentation functions to be softer than that for mesons. These predictions are in good accord with recent measurements of the spectra of baryons produced in e+e- annihilation. The model relates the degree of softening of the baryon fragmentation function to the probability of producing mesons between baryon and anti-baryon. © 1989.

Abstract:

Data on jet masses, resulting from the decomposition of e+e- hadronic final states into two hemispheres, are presented at centre of mass energies between 12 and 43.5 GeV. Comparisons are made with bare O(αs2) QCD predictions as well as with QCD based fragmentation models. Values for αs and {Mathematical expression} are determined, both with and without hadronization effects included. Upper and lower limits for {Mathematical expression} independent of fragmentation models have been determined to be 0.480±0.025 GeV and 0.047±0.007 GeV respectively. © 1989 Springer-Verlag.

Abstract:

A b enrichment technique using the long B lifetime has been developed, by which ∼600 hadronic events with >65%b purity are obtained. The properties of the associated jets are studied, with comparisons made between them and those in hadronic data in which b quarks make up only 10% of the total, and jets in Monte Carlo events. The distributions in rapidity and multiplicity yield two new determinations of the fragmentation variable z for b hadrons and confirm that the b fragmentation function is hard. We also present the first measurement of the relative strength of the strong interaction coupling of the b quark compared with the average of all flavours. © 1989 Springer-Verlag.