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Search for neutral Higgs bosons in Z0 decays using the OPAL detector at LEP

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Zeitschrift für Physik C Particles and Fields

Abstract

A search for neutral Higgs bosons has been performed using the full sample of Z0 decays collected by the OPAL detector at LEP up to 1995. The data were taken at centre-of-mass energies between 88 GeV and 95 GeV and correspond to an integrated luminosity of approximately 160 pb−1. The present search addresses the processes Z0→H0Z* and h0Z*, where H0 is the Higgs boson predicted by the Standard Model and h0 the lightest neutral scalar Higgs boson predicted in the framework of the Minimal Supersymmetric Standard Model. For the virtual Z0 boson, Z*, the following decay channels are considered: Z*→vv̅, e+e− and μ+μ−. Two candidate events have been found in the vv̅H0 channel and one in the μ+μ−H0 channel. Combined with earlier searches, the present search excludes the SM Higgs boson, at the 95% confidence level (CL), from the mass range below 59.6 GeV. In the framework of the Minimal Supersymmetric Standard Model, allowing a wide range of variation for most relevant model parameters, a 95% CL lower limit of 44.3 GeV is obtained for the mass of the h0 boson. Combined with earlier direct searches for the Higgs boson pair production process Z0→h0A0 and with measurements of the Z0 line shape, a 95% CL lower limit of 23.5 GeV is obtained for the mass of the pseudoscalar Higgs boson A0, assuming tan β≥ 1.

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The OPAL Collaboration. Search for neutral Higgs bosons in Z0 decays using the OPAL detector at LEP. Z Phys C - Particles and Fields 73, 189–199 (1997). https://doi.org/10.1007/s002880050309

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  • DOI: https://doi.org/10.1007/s002880050309

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