Single squark production at e+e- colliders

Single squark production is examined at present and next-generation e⁺e^- machines. In addition to total cross sections, missing energy and angular distributions are discussed which could allow detection of these events despite rather small rates.     

Supersymmetric Higgs boson pair production: Discovery prospects at hadron colliders

We study the potential of hadron colliders in the search for the pair production of neutral Higgs bosons in the framework of the minimal supersymmetric standard model. We perform a detailed signal and background analysis, working out efficient kinematical cuts for the extraction of the signal. The important role of squark loop contributions to the signal is re-emphasized. If the signal is sufficiently enhanced by these contributions, it could even be observable at the next run of the upgraded Tevatron collider in the near future. At the LHC the pair production of light and heavy Higgs bosons might be detectable simultaneously. Received: 23 February 2000 / Revised version: 18 April 2000 / Published online: 31 August 2000     

Six-fermion production and Higgs boson physics at future e^+ e^- colliders

The six-fermion production processes , with all the lepton flavours and , relevant to the study of the intermediate-mass Higgs boson at future linear colliders are analysed. A Monte Carlo program, taking into account the whole set of tree-level scattering amplitudes and the relevant radiative effects, is developed to provide integrated cross-sections and generation of unweighted events. The complete calculation is compared with the available results of real Higgs production, and the opportunities of precision studies with event generation are discussed, demonstrating the relevance of a full six-fermion calculation. Numerical results for integrated cross-sections with various kinematical cuts and including radiative effects are given and commented. In the analysis of event samples, several distributions are studied and found to be sensitive to the presence and to the properties of the Higgs boson. Received: 20 December 1998 / Published online: 27 April 1999     

NLO electroweak corrections to Higgs boson production at hadron colliders

Results for the complete NLO electroweak corrections to Standard Model Higgs production via gluon fusion are included in the total cross section for hadronic collisions. Artificially large threshold effects are avoided working in the complex-mass scheme. The numerical impact at LHC (Tevatron) energies is explored for Higgs mass values up to 500 GeV (200 GeV). Assuming a complete factorization of the electroweak corrections, one finds a +5% shift with respect to the NNLO QCD cross section for a Higgs mass of 120 GeV both at the LHC and the Tevatron. Adopting two different factorization schemes for the electroweak effects, an estimate of the corresponding total theoretical uncertainty is computed.     

Soft-gluon resummation for pseudoscalar Higgs boson production at hadron colliders

We compute the threshold-resummed cross section for pseudo-scalar MSSM Higgs boson production by gluon fusion at hadron colliders. The calculation is performed at next-to-next-to leading logarithmic accuracy. We present results for both the LHC and Tevatron Run II. We analyze the factorization and renormalization scale dependence of the results, finding that after performing the resummation the corresponding cross section can be computed with an accuracy better than 10%.