3,099 research outputs found
The ATLAS discovery potential for a heavy charged Higgs boson in gg->tbH^{+-} with H^{+-}->tb
The feasibility of detecting a heavy charged Higgs boson,
m(H^{+-})>m(t)+m(b), decaying in the H^{+-}->tb channel is studied with the
fast simulation of the ATLAS detector. We study the gg->H^{+-}tb production
process at the LHC which together with the aforementioned decay channel leads
to four b-quarks in the final state. The whole production and decay chain reads
gg->H^{+-}tb->t\bar{t}b\bar{b}->b\bar{b}b\bar{b}l\nu\bar{q}q'. Combinatorial
background is a major difficulty in this multi-jet environment but can be
overcome by employing multivariate techniques in the event reconstruction.
Requiring four b-tagged jets in the event helps to effectively suppress the
Standard Model backgrounds but leads to no significant improvement in the
discovery potential compared to analyses requiring only three b-tagged jets.
This study indicates that charged Higgs bosons can be discovered at the LHC up
to high masses (m(H^{+-})>400 GeV) in the case of large tan(beta)
Pair production of charged Higgs scalars from electroweak gauge boson fusion
We compute the contribution to charged Higgs boson pair production at the
Large Hadron Collider (LHC) due to the scattering of two electroweak (EW) gauge
bosons, these being in turn generated via bremsstrahlung off incoming quarks: q
q --> q q V^*V^* --> q q H^+H^- (V=gamma,Z,W^{+/-}). We verify that the
production cross section of this mode is tan beta independent and show that it
is smaller than that of H^+H^- production via q q-initiated processes but
generally larger than that of the loop-induced channel gg --> H^+H^-. Pair
production of charged Higgs bosons is crucial in order to test EW symmetry
breaking scenarios beyond the Standard Model (SM). We show that the detection
of these kind of processes at the standard LHC is however problematic, because
of their poor production rates and the large backgrounds.Comment: 22 pages, latex, 8 figures (largely revised version to appear in JPG
ATLAS discovery potential for a heavy charged Higgs boson
The sensitivity of the ATLAS detector to the discovery of a heavy charged
Higgs boson is presented. Assuming a heavy SUSY spectrum, the most promising
channels above the top quark mass are and
which provide coverage in the low and high
regions up to GeV. The achievable precisions on the
charged Higgs mass and determination are also discussed. The
channel, though restricted to a small MSSM parameter
space, shows a viable signal in NMSSM where the parameter space is less
constrained. The observation of the channel may
constitute a distinctive evidence for models with singlet neutrinos in large
extra dimensions.Comment: 18 page
Charged Higgs Boson Pairs at the LHC
We compute the cross section for pair production of charged Higgs bosons at
the LHC and compare the three production mechanisms. The bottom-parton
scattering process is computed to NLO, and the validity of the bottom-parton
approach is established in detail. The light-flavor Drell-Yan cross section is
evaluated at NLO as well. The gluon fusion process through a one-loop amplitude
is then compared with these two results. We show how a complete sample of
events could look, in terms of total cross sections and distributions of the
heavy final states.Comment: 15 pages with 8 figure
Determining the ratio of the H^+ -> \tau \nu to H^+ -> t b-bar decay rates for large \tan\beta at the Large Hadron Collider
We present results on the determination of the observable ratio R=BR(H^+ ->
\tau \nu)/BR(H^+ -> t b-bar) of charged Higgs boson decay rates as a
discriminant quantity between Supersymmetric and non-Supersymmetric models.
Simulation of measurements of this quantity through the analysis of the charged
Higgs production process gb-> t b H^+ and relative backgrounds in the two above
decay channels has been performed in the context of ATLAS. A ~12-14% accuracy
on R can be achieved for \tan\beta=50, \mHc=300-500 GeV and after an integrated
luminosity of 300 fb^-1. With this precision measurement, the Large Hadron
Collider (LHC) can easily discriminate between models for the two above
scenarios, so long as \tan\beta > 20.Comment: LaTeX, 11 pages, 3 figures, 3 tables, Contribution to the Les Houches
workshop ``Physics at TeV Colliders'', 26 May - 6 June, 200
Discovery potential for a charged Higgs boson decaying in the chargino-neutralino channel of the ATLAS detector at the LHC
We have investigated charged Higgs boson production via the gluon-bottom
quark mode, gb -> tH+, followed by its decay into a chargino and a neutralino.
The calculations are based on masses and couplings given by the Minimal
Supersymmetric Standard Model (MSSM) for a specific choice of MSSM parameters.
The signature of the signal is characterized by three hard leptons, a
substantial missing transverse energy due to the decay of the neutralino and
the chargino and three hard jets from the hadronic decay of the top quark. The
possibility of detecting the signal over the Standard Model (SM) and non-SM
backgrounds was studied for a set of tanBeta and mA. The existence of 5-sigma
confidence level regions for H+ discovery at integrated luminosities of 100
fb-1 and 300 fb-1 is demonstrated, which cover also the intermediate region 4 <
tanBeta < 10 where H+ decays to SM particles cannot be used for H+ discovery
Dark Matter and Collider Phenomenology with two light Supersymmetric Higgs Bosons
Recently, it has been pointed out that two different excesses of events
observed at LEP could be interpreted as the CP-even Higgs bosons of the MSSM
with masses of approximately 98 and 114 GeV. If this is the case, the entire
MSSM Higgs sector is required to be light. In this article, we explore such a
scenario in detail. We constrain the Higgs and supersymmetric spectrum using
physics constraints as well as the magnetic moment of the muon. We then
point out the implications for neutralino dark matter -- next generation direct
detection experiments will be sensitive to all MSSM models with such a Higgs
sector. Finally, we find that all models outside of a very narrow corridor of
the parameter space have a charged Higgs boson which will be observed at the
LHC. In those exceptional models which do not contain an observable charged
Higgs, a light top squark will always be seen at the LHC, and likely at the
Tevatron.Comment: 12 pages, 18 figure
A Nuclear Physics Program at the ATLAS Experiment at the CERN Large Hadron Collider
The ATLAS collaboration has significant interest in the physics of
ultra-relativistic heavy ion collisions. We submitted a Letter of Intent to the
United States Department of Energy in March 2002. The following document is a
slightly modified version of that LOI. More details are available at:
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/SM/ionsComment: Letter of Intent submitted to the United States Department of Energy
Nuclear Physics Division in March 2002 (revised version
Prospects for Higgs boson searches with ATLAS Part I: Higgs decays to gauge bosons
The discovery prospect of the ATLAS detector for the Higgs boson decays to gauge bosons is reviewe
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