DOI 10.1007/s100520000345
Search for unstable heavy and excited leptons at LEP2
The OPAL Collaboration
G.Abbiendi
- et al.
2 Dipartimento di Fisica dell' Università di Bologna and INFN,
40126 Bologna, Italy
Received: 29 November 1999 / Published online: 6 March 2000 - © Springer-Verlag 2000
Abstract
Searches for unstable neutral and charged
heavy leptons, N and
,
and
for excited states of neutral and charged leptons,
,
,
,
and
,
have been performed in
collisions using
data collected by the OPAL detector at LEP.
The data analysed correspond to an integrated luminosity of about
58 pb-1 at a centre-of-mass energy of 183 GeV, and
about 10 pb-1 each at 161 GeV and 172 GeV.
No evidence for new particles was found.
Lower limits on the masses of unstable heavy and excited leptons
are derived.
From the analysis of charged-current, neutral-current, and photonic decays
of singly produced excited leptons,
upper limits are determined for
the ratio of the coupling to the compositeness scale,
,
for masses up to
the kinematic limit. For excited leptons, the limits are established
independently of the relative values
of the coupling constants f and
.
Copyright Società Italiana di Fisica, Springer-Verlag 2000