145 research outputs found
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
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 gg -> H+ H- are calculated with the complete set of MSSM particles.
Numerical results are presented for the cross section of the inclusive hadron
process p p -> gg -> H+ H- + X at the LHC.Comment: 25 pages, 7 figures, 3 typos corrected, acknowledgement added,
coincides now with published versio
Charged Higgs Production in Association with W Boson at Photon Colliders
It is important to explore the Higgs sector in order to identify the model
beyond the standard model. We study the charged Higgs production in the
mode of a linear collider (LC) with 1000 GeV center of mass
energy. We show that the cross sections for the
processes can be significantly enhanced in the two Higgs doublet model (THDM).
The cross section can reach 0.1 - 100 fb which is comparable to other charged
Higgs boson production processes at a photon collider. While for other
processes the cross sections are too small for GeV, fb can be expected in the processes for
GeV when GeV. Therefore, even if the charged
Higgs bosons can not be detected at the Large Hadron Collider (LHC), and even
if the charged Higgs bosons are too heavy to be detected in other charged Higgs
boson production processes at the LC, it may be possible to detect them in this
process.Comment: To appear in the proceedings of 2005 International Linear Collider
Workshop (LCWS 2005), Stanford, California, 18-22 Mar 200
Single Charged MSSM Higgs-boson production at a Linear Collider
In the Minimal Supersymmetric Standard Model we present the calculation of
the single charged Higgs-boson production in the gamma W- or Z W-fusion and the
charged Higgs strahlung channel, e^+ e^- -> e nu H^\pm. The set of all O(alpha)
corrections arising from loops of Standard Model fermions and scalar fermions
are taken into account. Contrary to the case of single neutral heavy CP-even
Higgs-boson production, for the charged Higgs boson we find for all the
parameter space of the typical benchmark scenarios a cross section smaller than
\sim 0.01 fb for sqrt(s)/2 \lessim M_H^\pm.Comment: 4 pages, 2 figure
New HiggsBounds from LEP and the Tevatron
We review the program HiggsBounds that tests theoretical predictions of
models with arbitrary Higgs sectors against the exclusion bounds obtained from
the Higgs searches at LEP and the Tevatron. We explicitly list the bounds that
have been added after the first release of HiggsBounds.Comment: 4 pages, talk given at SUSY09, Boston, June 200
Precision Calculations for Associated WH and ZH Production at Hadron Colliders
Recently the next-to-next-to-leading order QCD corrections and the
electroweak O(alpha) corrections to the Higgs-strahlung processes ppbar/pp ->
WH/ZH + X have been calculated. Both types of corrections are of the order of
5-10%. In this article the various corrections are briefly discussed and
combined into state-of-the-art predictions for the cross sections. The
theoretical uncertainties from renormalization/factorization scales and from
the parton distribution functions are discussed.Comment: 8 pages, Contributed to 3rd Les Houches Workshop: Physics at TeV
Collider
Next-to-leading order QCD predictions for the hadronic +jet production
We calculate the next-to-leading order(NLO) QCD corrections to the
production in association with a jet at hadron colliders. We study the impacts
of the complete NLO QCD radiative corrections to the integrated cross sections,
the scale dependence of the cross sections, and the differential cross sections
(, ) of the final -,
Higgs-boson and jet. We find that the corrections significantly modify the
physical observables, and reduce the scale uncertainty of the LO cross section.
Our results show that by applying the inclusive scheme with and taking , , the
K-factor is 1.15 for the process at the Tevatron,
while the K-factors for the processes and
at the LHC are 1.12 and 1.08 respectively. We conclude that to understand the
hadronic associated production, it is necessary to study the NLO QCD
corrections to production process which is part of the inclusive
production.Comment: 26 pages, 27 figures, accepted by Phys. Rev.
On MSSM charged Higgs boson production in association with an electroweak W boson at electron positron colliders
We present a calculation of the cross section for the process e+ e- --> W+/-
H-/+ in the minimal supersymmetric standard model (MSSM) and the Two Higgs
Doublet Model (THDM). We study the basic features of the MSSM prediction for
some distinctive parameter scenarios. We find large effects from virtual
squarks for scenarios with large mixing in the stop sector which can lead to a
cross section vastly different from a THDM with identical Higgs sector
parameters. We investigate this interesting behaviour in more detail by
thoroughly scanning the MSSM parameter space for regions of large cross
section. For a charged Higgs boson too heavy to be pair-produced at such a
machine, it turns out that a large MSSM cross section with a good chance of
observation is linked to a squark mass scale below 600 GeV and a considerable
amount of mixing in either the stop and sbottom sector.Comment: 25 pages, 10 figures (two in colour). Substantially improved on the
MSSM parameter restrictions taken into account. Added some reference
Jet-veto in bottom-quark induced Higgs production at next-to-next-to-leading order
We present results for associated Higgs+n-jet production in bottom quark
annihilation, for n=0 and n>=1 at NNLO and NLO accuracy, respectively. We
consider both the cases with and without b-tagging. Numerical results are
presented for parameters relevant for experiments at the LHC.Comment: 27 pages, 13 figures, 8 table
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