Study of hadronization using energy flow from e/sup +/e/sup -/ annihilation into quarks and gluons at. sqrt. s of 29 GeV

Abstract

We have made a high statistics study of QCD jets produced in e/sup +/e/sup -/ annihilations at ..sqrt..s of 29 GeV and observed in the MAC detector located at the PEP storage ring at SLAC. The MAC detector uses calorimetry and provides a homogeneous response over much of its 98% . 4..pi.. sr instrumented solid angle. A data sample of well reconstructed hadronic events was selected by requiring that E/sub vis/ in the calorimeters be near ..sqrt..s, and almost all the energy be deposited in the central calorimeters. Fits of the jet transverse energy flow are made to the data using String (STR) model and several types of Independent Jet (IJM) model hypotheses, where ..alpha../sub s/, the strong coupling constant, and sigma/sub q/, the width of the secondary quark P/sub perpendicular/ distribution, are free parameters. The fits to O(..alpha../sub s//sup 2/ using MS-bar renormalization yield ..alpha../sub s/ approx.0.17 with the STR hypothesis, and ..alpha../sub s/ approx.0.12 with the various IJM hypotheses. The correlations between ..alpha../sub s/ and sigma/sub q/ are examined. Detailed comparisons were made with other experimental results. The energy flow projected onto the event plane of 3-jet events selected from the above data sample was studied. The datamore » shows an asymmetric energy flow around the thin jet. Such an asymmetry was predicted by the STR model, and a cluster model (Webber) incorporating soft gluon interference. The various IJM models show no such asymmetry. We associate this asymmetry with coherence effects during hadronization. 106 refs., 58 figs., 18 tabs.« less