Search for non-minimal Higgs bosons in Z[sup 0] decays with the L3 detector at LEP
A general search for neutral and charged Higgs bosons in e[sup +]e[sup [minus]] collisions at the Z[sup 0] resonance is reported. No assumption that the Higgs sector consists of one doublet as in the Minimal Standard Model (MSM) is made. In the MSM of electroweak interactions, a single Higgs doublet generates the masses for the gauge bosons and for the charged fermions via spontaneous breaking of the gauge symmetry. With only one doublet, Higgs boson production and decay properties depend only on the Higgs boson mass. The LEP experiments have searched for the MSM Higgs boson and exclude it for masses less than about 60 GeV. It is quite possible that the actual scalar sector in nature has more than one doublet of Higgs bosons or has Higgs bosons in other multiplets. This is expected in many theories that go beyond the Standard Model. In Supersymmetric models, at least two Higgs doublets are predicted. A model with two Higgs doublets illustrates some processes that occur in more general models. If the Higgs sector contains more than a single doublet, rates for bremsstrahlung of the lightest Higgs boson from the Z[sup 0] are no longer uniquely predicted and are generally lower than in the MSM. At the same time, with a richer Higgs sector, pairs of Higgs particles can be produced in Z[sup 0] decays. Therefore, if one is to find a non-MSM Higgs boson at LEP, one must search for bremsstrahlung at lower rates than predicted in the MSM and for Higgs boson pair-production. This work is based on the 1990 and 1991 L3 data sample which totals 408,000 hadronic Z[sup 0] decays, collected at center-of-mass energies between 88.2 and 94.3 GeV. No Higgs signal inconsistent with background is observed in any of the decay channels analyzed. From the results of direct searches, model-independent limits on Higgs boson bremsstrahlung and on Higgs boson pair-production from the Z[sup 0] are presented. The bremsstrahlung limits are interpreted in a general two-doublet model.
- Research Organization:
- California Univ., San Diego, La Jolla, CA (United States)
- OSTI ID:
- 7161182
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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HIGGS BOSONS
DETECTION
MASS
ELECTRON-POSITRON COLLISIONS
GEV RANGE 10-100
COLLISIONS
ELECTRON COLLISIONS
ELEMENTARY PARTICLES
ENERGY RANGE
GEV RANGE
POSITRON COLLISIONS
POSTULATED PARTICLES
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