DOI 10.1007/s100520000286
Search for neutral Higgs bosons in e+ e- collisions at 189GeV
The OPAL Collaboration
G.Abbiendi 2 - et al.
Dipartimento di Fisica dell' Università di Bologna and INFN,
40126 Bologna, Italy
Received: 9 July 1999 / Published online: 27 January 2000 - © Springer-Verlag 2000 2000
Abstract
Searches for the neutral Higgs bosons predicted by the
Standard Model (SM) and the Minimal Supersymmetric extension
of the Standard Model (MSSM) have been performed
with the OPAL detector at LEP. Approximately 170pb-1 of
e+ e- collision data collected at
GeV were used to search for Higgs boson production in the
SM process
and the MSSM processes
and
.
The searches
are sensitive to the
and
decay modes of the Higgs bosons, and also to the MSSM decay mode
.
OPAL
search results at lower centre-of-mass energies have been incorporated
in the limits, which are valid at the 95% confidence level. For the SM
Higgs boson, a lower mass bound of 91.0GeV is obtained. In the MSSM,
the limits are
mH >74.8GeV and
mA
>76.5GeV, assuming
,
that the mixing of the scalar
top quarks is either zero or maximal, and that the soft SUSY-breaking
masses are 1TeV. For the case of zero scalar top mixing, the values
of
between 0.72 and 2.19 are excluded.
Copyright Springer-Verlag 2000