Four-jet final state production in e +e − collisions at centre-of-mass energies ranging from 130 to 184 GeV

The four jet topology is analysed in the ALEPH data taken between November 1995 and October 1997, at centre-of-mass energies ranging from 130 to 184 GeV. While an unexpected accumulation of events with a dijet mass sum around 105 GeV/ c 2 had been observed during the first run in 1995 at 130/136 GeV, corresponding to an integrated luminosity of 5.7 pb −1, no significant differences between data and standard model prediction is seen, either in the high energy runs (81.1 pb −1 taken at centre-of-mass energies from 161 to 184 GeV) or in the 7.1 pb −1 recorded during a new short run at 130/136 GeV in 1997. We have found no other explanation for the earlier reported “four jet anomaly” than a statistical fluctuation.