Search for New Particles at LEP

The latest preliminary results of the searches for Higgs bosons and Supersymmetric particles at LEP are reviewed. The results include the data-taking in 1999 up to center-of-mass energies of 196 GeV. The combination of the results from the four LEP experiments leads to a significant increase of the detection sensitivity. No indication of a signal has been observed. In the Standard Model (SM) a lower limit of 102.6 GeV on the mass of the Higgs boson is set at 95% CL. In extended models, stringent limits are also set on the HZZ coupling. Interpretations in the Minimal extension of the Supersymmetric Standard Model (MSSM) are given and the importance of general MSSM parameter scans is emphasized. In general scans, the limit on the mass of the lightest scalar Higgs boson is about 7 GeV lower in comparison with benchmark results. The data also constrains charged Higgs bosons of a general two-doublet model and Supersymmetric partners of the SM particles.Comment: 16 pages, 38 figure

A Cut Discontinuous Galerkin Method for Coupled Bulk-Surface Problems

We develop a cut Discontinuous Galerkin method (cutDGM) for a diffusion-reaction equation in a bulk domain which is coupled to a corresponding equation on the boundary of the bulk domain. The bulk domain is embedded into a structured, unfitted background mesh. By adding certain stabilization terms to the discrete variational formulation of the coupled bulk-surface problem, the resulting cutDGM is provably stable and exhibits optimal convergence properties as demon- strated by numerical experiments. We also show both theoretically and numerically that the system matrix is well-conditioned, irrespective of the relative position of the bulk domain in the background mesh.Comment: 22 pages, 4 figures, 1 tabl

Cross-sections and branching ratios for charged Higgs searches

For the preparation of the experimental search for charged Higgs bosons at the LHC detailed studies have been made to determine the expected charged Higgs boson production cross-sections and decay branching ratios at sqrts = 14 TeV. In the mass regime below the t-quark mass the expected production cross-sections are discussed using PYTHIA and FeynHiggs program packages based on the decay t to H^+b. For higher masses Next-to-Leading-Order (NLO calculations have been used, and particular attention has been given to the intermediate-mass region. The decay branching ratios have been studied with the program packages FeynHiggs and HDecay. Higher-order corrections (Delta_b corrections) in the MSSM are consistently taken into account. Two benchmark scenarios are considered, one of them the `mhmax'.Comment: 8 pages, contribution to the Workshop on Prospects for Charged Higgs Discovery at Colliders, 16-19 September 2008, Uppsala, Swede