Associated production of charged Higgs bosons and top quarks with POWHEG

The associated production of charged Higgs bosons and top quarks at hadron colliders is an important discovery channel to establish the existence of a non-minimal Higgs sector. Here, we present details of a next-to-leading order (NLO) calculation of this process using the Catani–Seymour dipole formalism and describe its implementation in POWHEG, which allows to match NLO calculations to parton showers. Numerical predictions are presented using the PYTHIA parton shower and are compared to those obtained previously at fixed order, to a leading order calculation matched to the PYTHIA parton shower, and to a different NLO calculation matched to the HERWIG parton shower with MC@NLO. We also present numerical predictions and theoretical uncertainties for various Two Higgs Doublet Models at the Tevatron and LHC.     

Search for doubly charged Higgs bosons with lepton-flavor-violating decays involving tau leptons

We search for pair production of doubly charged Higgs particles (H+/- +/-) followed by decays into electron-tau (etau) and muon-tau (mutau) pairs using data (350 pb(-1) collected from [over]pp collisions at sqrt[s]=1.96 TeV by the CDF II experiment. We search separately for cases where three or four final-state leptons are detected, and combine results for exclusive decays to left-handed etau (mutau) pairs. We set an H+/- +/- lower mass limit of 114(112) GeV/c(2) at the 95% confidence level.     

Pair production of charged MSSM Higgs bosons by gluon fusion

The production of pairs of charged Higgs bosons as predicted by the minimal supersymmetric standard model (MSSM) via the gluon fusion mechanism is investigated. The amplitudes at the leading one-loop order for the parton process are calculated with the complete set of MSSM particles. Numerical results are presented for the cross section of the inclusive hadron process at the LHC. Received: 20 September 1999 / Published online: 27 January 2000     

Testing supersymmetry in the associated production of CP-odd and charged Higgs bosons

In the Minimal Supersymmetric Standard Model (MSSM), the masses of the charged Higgs boson (H±) and the CP-odd scalar (A) are related by MH+2=MA2+mW2. Furthermore, because the coupling of W−–A–H+ is fixed by gauge interaction, the tree level production rate of depends only on one supersymmetry parameter—the mass (MA) of A. We show that to a good approximation this conclusion also holds at the one-loop level. Consequently, this process can be used to distinguish MSSM from its alternatives (such as a general two-Higgs-doublet model) by verifying the above mass relation, and to test the prediction of the MSSM on the product of the decay branching ratios of A and H± in terms of only one single parameter—MA.     

Higgs charged bosons and the problem of solar neutrinos

For a model with the SU(2)L×SU(2)_R×U(1)_{B−L} gauge group, the passage of neutrino flux through a substance is studied. It is shown that Higgs charged physical bosons can considerably change the potential of neutrino interaction with the solar substance. An analytical expression for the survival probability of left-handed electron neutrinos is derived in the two-flavor approximation. Yanka Kupala Grodno State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 32–37, January, 2000.     

Production of charged Higgs bosons at LHC in light-quark annihilation

The CMS potential (at LHC) for seeking the production of a charged Higgs boson is investigated for large values of tan β (between 20 and 50) and a relatively light charged Higgs boson M _H = 200–400 GeV). A simple parametrization is proposed for the

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distributions of signal and background events. The possibility of measuring the mass of the charged Higgs boson and tan β is investigated.

     

Pair production of charged Higgs bosons in the left–right twin Higgs model at the ILC and LHC

The left–right twin Higgs (LRTH) model predicts the existence of a pair of charged Higgs bosons φ^±. In this paper, we study the production of the charged Higgs boson pair φ^± at the international linear collider (ILC) and the CERN large hadron collider (LHC). The numerical results show that the production rates are at the level of several tens fb at the ILC, and the process e⁺e^-→φ⁺φ^- can produce adequately distinct multi-jet final states. We also discuss the charged Higgs boson pair production via the process qq̄→φ⁺φ^- at the LHC and estimate in this case the production rates. We find that, as long as the charged Higgs bosons are not too heavy, they can be abundantly produced at the LHC. The possible signatures of these new particles might be detected at the ILC and LHC experiments. PACS 12.60.Fr; 14.80.Mz; 14.65.Ha; 12.15.Lk     

Search for charged Higgs bosons at LEP in general two Higgs doublet models

A search for pair-produced charged Higgs bosons was performed in the data collected by the DELPHI detector at LEP II at centre-of-mass energies from 189 GeV to 209 GeV. Five different final states, , , , and were considered, accounting for the major expected decays in type I and type II Two Higgs Doublet Models. No significant excess of data compared to the expected Standard Model processes was observed. The existence of a charged Higgs boson with mass lower than 76.7 GeV/c² (type I) or 74.4 GeV/c² (type II) is excluded at the 95% confidence level, for a wide range of the model parameters. Model independent cross-section limits have also been calculated.Received: 30 September 2003, Revised: 12 February 2004, Published online: 8 April 2004     

Some phenomenological predictions of charged Higgs bosons in electroweak interactions

Some phenomenological consequences of an extended Salam-Weinberg model are studied. In particular, the existence, or absence, ofe?μ asymmetry in beam-dump experiments is analyzed and an increase in same sign dilepton cross sections is shown to exist due to the contribution of charged Higgs-mediated diagrams. The model is shown to be compatible with experimental results for other processes.     

Decay properties of a class of doubly charged Higgs bosons

We study the leptonic decays of a doubly charged Higgs bosons class which is predicted by a model based on the SU_(3)C⊗SU_(2)L⊗U_(1)N$\mathrm{SU}{(3)}_C\otimes \mathrm{SU}{(2)}_L\otimes \mathrm{U}{(1)}_N$ electroweak gauge symmetry. In contrast to other models, decays into τ^±τ^±${\tau }^{\pm }{\tau }^{\pm }$ are largely dominant (99.5% or more). Coupling of these scalars to two standard charged gauge bosons are either zero or very suppressed. Couplings to two different flavor of charged leptons do not occur. Some coupling features imposed by symmetry and representation content lead to simple relationships between decay rates and doubly charged Higgs masses. Some of the parameters depend only on the decay widths and on the charged lepton masses. In order to clarify the relevance of our results, some aspects of this model are compared with the Higgs triplet model.