بررسی رویدادهای چند جتی در نابودی الکترون - پوزیترون

 Analysis of electron – positron annihilation into hadrons in the range of energies above 60 GeV shows that apart from two jet events, there are evidence for three jet events that according to the QCD theory interpreted as a gluon radiation by a quark. However, the higher order diagrams lead to four jet events. In this paper, we study the fragmentation of quarks and gluons into hadronic jets . Acoplanarity(AC), is a parameter for our analysis of four jet events.We expect that four jet events have AC values opposite to zero. This result is consistent with results obtained from the Monte Carlo studies as well as the results obtained at lower energies. Possible explanation for all these features will be explained in this paper .