Nuclear Physics B185 (1981) 365-381 © North-Holland Publishing Company QCD PREDICTIONS FOR FOUR-JET FINAL STATES IN e+e - ANNIHILATION (II). Angular correlations as a test of the triple-gluon coupling J.G. K()RNER Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany G. SCHIERHOLZ and J. WILLRODT II. Institut fiir Theoretische Physik der UniversitiitHamburg, Germany Received 23 January 1981 (Final version received 11 March 1981) We investigate beam-event correlations and correlations within the event in e+e - annihilation into four jets. An interesting possibility to "measure" the triple-gluon coupling is found. 1. Introduction In the last two years remarkable agreement between the order as predictions of QCD and the e+e - annihilation data has been found. The observation of 3-jet events is being interpreted as evidence for the existence of gluons [1]. At order 2 one also expects the occurrence of 4-jet events resulting from the perturbative processes e+e - ~ qqgg and e÷e - -~ qqqq. The cross sections of these two processes have been given and discussed in refs. [2, 3]. Supported by these cal- culations*, first evidence for 4-jet events has recently been reported by various groups [5]. Four-jet events are quite interesting to study as QCD shows its full gauge structure only in order a~. Despite the various qualitative and even semiquantitative pieces of evidence in favour of QCD, there is so far no convincing proof of the validity of QCD, and it would be extremely important to experimentally verify the effects of the gluon self-couplings. Four-jet events are quite favourable to such an analysis because of the dominance of the e+e - ~ qqgg cross section (which contains contributions from the triple-gluon coupling) over the e+e -~ qCtqC:lcross section [2]. As 4-jet events will be accumulating in the next few years, we shall look into the nature of 4-jet events in closer detail. Led by the task of finding tests which emphasize the more fundamental aspects of QCD, we suggest the study of beam- event correlations and correlations within the 4-jet events. The significance of the * The 4-jet amplitudes are also included in the event-generator programs [4] used at DESY. 365