A data sample corresponding to almost two million hadronic Z decays collected by the ALEPH detector at LEP has been searched for monojet events. Three events were found, in agreement with the expectation from the process e+e- --> gamma*nunuBAR, with gamma* --> ffBAR. Two events are hadronic, the third one being an e+e- pair. All monojet masses are in excess of 3 GeV/c2, and two of the events have large transverse momenta: 18.5 and 20.3 GeV/c. These kinematic characteristics are quite unlikely in the process e+e- --> gamma*nunuBAR. The probability of their occurrence increases substantially when processes involving further Z or W exchanges are taken into account, but still remains at the 5% level.
OBSERVATION OF MONOJET EVENTS AND TENTATIVE INTERPRETATION
ROLANDI, LUIGI;LIGABUE, FRANCO;LUSIANI, Alberto;
1994
Abstract
A data sample corresponding to almost two million hadronic Z decays collected by the ALEPH detector at LEP has been searched for monojet events. Three events were found, in agreement with the expectation from the process e+e- --> gamma*nunuBAR, with gamma* --> ffBAR. Two events are hadronic, the third one being an e+e- pair. All monojet masses are in excess of 3 GeV/c2, and two of the events have large transverse momenta: 18.5 and 20.3 GeV/c. These kinematic characteristics are quite unlikely in the process e+e- --> gamma*nunuBAR. The probability of their occurrence increases substantially when processes involving further Z or W exchanges are taken into account, but still remains at the 5% level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
