The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric Standard Model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of "benchmark" models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter tan β and, in some scenarios, on the masses of neutral Higgs bosons.

We study the Y (4260) production mechanism in e + e − annihilations in the framework of hadronic molecules and investigate the consequence of such a picture in different decay channels. In the hadronic molecule picture the Y (4260) is described as a mixture state composed of a long-ranged DD1(2420) + c.c. molecule state and a compact cc component. We show that the compositeness relation can still provide a reasonable constraint on the wavefunction renormalization parameter due to the dominance of the molecular component. Such a mechanism can be regarded as a natural consequence of the heavy quark spin symmetry (HQSS) breaking. This study elaborates the molecular picture for the Y (4260) in the e + e − annihilations and affirms that the cross section lineshape of e + e − →DD * π + c.c. in the vicinity of the Y (4260) should have a nontrivial behavior. In this framework we predict that the upper limit of the Y (4260) leptonic decay width is about 500 eV. We also investigate the coupling for D1(2420) → D * π in the 3 P0 quark model and examine the possible HQSS breaking effects due to the deviation from the | 1 P1 and | 3 P1 ideal mixing. This will in turn provide a constraint on the HQSS breaking coupling for the Y (4260) toDD1(2420) + c.c. via its cc component.

A search for the production and non-standard decay of a Higgs boson, h, into four taus through intermediate pseudoscalars, a, is conducted on 683 pb −1 of data collected by the ALEPH experiment at centre-of-mass energies from 183 to 209 GeV. No excess of events above background is observed, and exclusion limits are placed on the combined production cross section times branching ratio, ξ 2 = σ(e + e − →Zh). For m h < 107 GeV/c 2 and 4 < m a < 10 GeV/c 2 , ξ 2 > 1 is excluded at the 95% confidence level.

We calculate diquark correlation functions in the Landau gauge on the lattice using overlap valence quarks and 2+1-flavor domain wall fermion configurations. Quark masses are extracted from the scalar part of quark propagators in the Landau gauge. Scalar diquark quark mass difference and axial vector scalar diquark mass difference are obtained for diquarks composed of two light quarks and of a strange and a light quark. Light sea quark mass dependence of the results is examined. Two lattice spacings are used to check the discretization effects. The coarse and fine lattices are of sizes 24 3 × 64 and 32 3 × 64 with inverse spacings 1/a = 1.75(4) GeV and 2.33(5) GeV, respectively.