Associated W+/- H-/+ production at e+ e- and hadron colliders

We show some results in the minimal supersymmetric Standard Model (MSSM) and the two Higgs doublet model (THDM) for W+/- H-/+ production cross sections at e+ e- and hadron colliders. We demonstrate that the predictions for the cross sections in the two models can be vastly different. Observing these processes, once the existence of a charged Higgs is established, might shed some light on the underlying model for an extended Higgs sector.Comment: 8 pages, 5 figures, Contribution to SUSY 02, Hamburg, Germany, June 200

Production of Neutral Higgs + Jet at the LHC in the SM and the MSSM

The cross section prediction for the production of the lightest neutral Higgs boson in association with a high-p_T hadronic jet is presented in the framework of the minimal supersymmetric standard model (MSSM) and compared to the SM case. Prospects for the CERN Large Hadron Collider (LHC) are discussed.Comment: 4 pages, To appear in the Proceedings of SUSY 2003, held at the University of Arizona, Tucson, AZ, 5-10 June 200

Adaptive scanning - a proposal how to scan theoretical predictions over a multi-dimensional parameter space efficiently

A method is presented to exploit adaptive integration algorithms using importance sampling, like VEGAS, for the task of scanning theoretical predictions depending on a multi-dimensional parameter space. Usually, a parameter scan is performed with emphasis on certain features of a theoretical prediction. Adaptive integration algorithms are well-suited to perform this task very efficiently. Predictions which depend on parameter spaces with many dimensions call for such an adaptive scanning algorithm.Comment: 8 pages, 4 figure

Charged Higgs-boson production in association with an electron and a neutrino at electron-positron colliders

We present results of a calculation of the cross section for the production of a charged Higgs boson in association with an electron and a neutrino at electron-positron colliders (e+ e- -> H+ e- nu_e-bar, H- e+ nu_e). We study predictions for the cross section in the Minimal Supersymmetric Standard Model (MSSM) and the Two Higgs Doublet Model (THDM), highlighting possible differences. The process is effectively loop-induced in both models. Hence, the cross section is expected to be strongly model-dependent. Most notably, due to the presence of superpartners, the MSSM amplitude contains Feynman graphs of pentagon-type, which are not present in the THDM. This is the first complete one-loop calculation of the cross section for this process in the THDM and the MSSM. For both models, so far, only approximate results with limited ranges of validity were available. Our main aim here is to clarify several open questions in the existing literature on this process. Specifically, we will discuss the validity of the Heavy Fermion loop approximation in both models, and of the Fermion/Sfermion loop approximation in the MSSM.Comment: 21 pages, 8 figures, 1 tabl

Electroweak and Bottom Quark Contributions to Higgs Boson plus Jet Production

This paper presents predictions for jet pseudorapidity (eta) and transverse momentum (p_T) distributions for the production of the Standard Model Higgs boson in association with a high-p_T hadronic jet. We discuss the contributions of electroweak loops and of bottom-quark parton processes to the cross section. The latter arise in the five-flavour scheme. Predictions for the Tevatron and the Large Hadron Collider with 10 TeV collision energy are presented. For Higgs boson masses of 120 GeV, 160 GeV and 200 GeV, we find the maximal effects of the electroweak contributions to the Higgs plus jet p_T and eta distribution to be -14 % and -5.3 %, respectively, for the Tevatron, and -3 % and -2 %, respectively, for the LHC. For the maximal contribution of bottom-quark parton processes to the p_T and eta distribution, we find +3 % and + 2.5 %, respectively, for the Tevatron, and +3.5 % and +3 %, respectively, for the LHC. A separate study of the Higgs + b-jet cross section demonstrates that a calculational approach which respects the hierarchies of Yukawa couplings yields a leading order cross section prediction which is more accurate in the high-p_T regime than conventional approaches.Comment: 25 pages, 14 figure

Towards a Realistic MSSM Prediction for Neutrino-nucleon Deep-inelastic Scattering

We discuss the radiative corrections to charged and neutral current deep-inelastic neutrino--nucleon scattering in the minimal supersymmetric standard model (MSSM). In particular, we study deviations, delta_R^nu(nu-bar), from the Standard Model prediction for the ratios of neutral- to charged-current cross sections, taking into account all sources for deviations in the MSSM, i.e. different contributions from virtual Higgs bosons and virtual superpartners. Our calculation includes the full q^2 dependence of the one-loop amplitudes, parton distribution functions and a NuTeV-inspired process kinematics. We present results of a scan of delta_R^nu(nu-bar) over the relevant MSSM parameter space.Comment: 5 pages, 2 figures, to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 200

Enhancement of W+/- H-/+ Production at Hadron Colliders in the Two Higgs Doublet Model

We discuss the associated W+/- H-/+ production at the CERN Large Hadron Collider. The dependence of the hadronic cross section on the Higgs sector parameters is investigated in detail in the framework of the general Two Higgs Doublet Model (THDM). We study the possible enhancement of the THDM prediction for the cross section compared to the prediction of the Minimal Supersymmetric Standard Model (MSSM). We find regions in the THDM parameter space where the THDM prediction can exceed the one of the MSSM by two orders of magnitude. These regions of large cross section are in agreement with theoretical bounds on the model, derived from the requirement of vacuum stability and perturbative unitarity, and are not excluded by experimental constraints.Comment: 19 pages, 5 figure

MSSM Higgs bosons associated with high-pT jets at hadron colliders

The cross section for the production of the lightest neutral Higgs boson in association with a high-pT hadronic jet, calculated in the framework of the minimal supersymmetric standard model (MSSM), is presented. The expectations for the hadronic cross section at the Large Hadron Collider are discussed using reasonable kinematical cuts. In particular the contributions from superpartner loops to the cross section and their dependence on the parameters of the MSSM are investigated and found to be significant. Comparisons show that the production rate for h0 + jet in the MSSM can differ widely from the corresponding standard-model prediction.Comment: 20 page