456 research outputs found
Robust LHC Higgs Search in Weak Boson Fusion
We demonstrate that an LHC Higgs search in weak boson fusion production with
subsequent decay to weak boson pairs is robust against extensions of the
Standard Model or MSSM involving a large number of Higgs doublets. We also show
that the transverse mass distribution provides unambiguous discrimination of a
continuum Higgs signal from the Standard Model.Comment: 12p, 2 figs., additional comments on backgrounds, version to appear
in PR
Determining the Structure of Higgs Couplings at the LHC
Higgs boson production via weak boson fusion at the CERN Large Hadron
Collider has the capability to determine the dominant CP nature of a Higgs
boson, via the tensor structure of its coupling to weak bosons. This
information is contained in the azimuthal angle distribution of the two
outgoing forward tagging jets. The technique is independent of both the Higgs
boson mass and the observed decay channel.Comment: 5 pages, 4 figures, version accepted for publication in PR
Pair production of neutral Higgs bosons at the CERN Large Hadron Collider
We study the hadroproduction of two neutral Higgs bosons in the minimal
supersymmetric extension of the standard model, which provides a handle on the
trilinear Higgs couplings. We include the contributions from quark-antiquark
annihilation at the tree level and those from gluon-gluon fusion, which
proceeds via quark and squark loops. We list compact results for the tree-level
partonic cross sections and the squark loop amplitudes, and we confirm previous
results for the quark loop amplitudes. We quantitatively analyze the hadronic
cross sections at the CERN Large Hadron Collider assuming a favorable
supergravity-inspired scenario.Comment: 22 pages (Latex), 16 figures (Postscript). Discussion of theoretical
uncertainties and background processes added. Accepted for publication in
Phys. Rev.
Phenomenology of Mirror Fermions in the Littlest Higgs Model with T-Parity
Little Higgs models are an interesting alternative to explain electroweak
symmetry breaking without fine-tuning. Supplemented with a discrete symmetry
(T-parity) constraints from electroweak precision data are naturally evaded and
also a viable dark matter candidate is obtained. T-parity implies the existence
of new (mirror) fermions in addition to the heavy gauge bosons of the little
Higgs models. In this paper we consider the effects of the mirror fermions on
the phenomenology of the littlest Higgs model with T-parity at the LHC. We
study the most promising production channels and decay chains for the new
particles. We find that the mirror fermions have a large impact on the
magnitude of signal rates and on the new physics signatures. Realistic
background estimates are given.Comment: 13 p
Jet Substructure Without Trees
We present an alternative approach to identifying and characterizing jet
substructure. An angular correlation function is introduced that can be used to
extract angular and mass scales within a jet without reference to a clustering
algorithm. This procedure gives rise to a number of useful jet observables. As
an application, we construct a top quark tagging algorithm that is competitive
with existing methods.Comment: 22 pages, 16 figures, version accepted by JHE
The Triple Higgs Boson Self-Coupling at Future Linear e+e- Colliders Energies: ILC and CLIC
We analyzed the triple Higgs boson self-coupling at future
colliders energies, with the reactions . We evaluate the total cross-sections for both and ,
and calculate the total number of events considering the complete set of
Feynman diagrams at tree-level. We vary the triple coupling
within the range and +2. The numerical
computation is done for the energies expected to be available at a possible
Future Linear Collider with a center-of-mass energy and a luminosity 1000 . Our analysis is also extended to a
center-of-mass energy 3 and luminosities of 1000 and 5000
. We found that for the process , the
complete calculation differs only by 3% from the approximate calculation
, while for the process , the expected number of events, considering the decay products of both
and , is not enough to obtain an accurate determination of the triple Higgs
boson self-coupling.Comment: 19 pages, 12 figure
Enhancement of the Higgs pair production at LHC; the MSSM and extra dimension effects
The neutral Higgs pair production at the LHC is studied in the MSSM, the
large extra dimensional (ADD) model and the Randall-Sundrum (RS) model, where
the total cross section can be significantly enhanced compared to that in the
SM. The , invariant mass and rapidity distributions of each model have
been shown to be distinctive: The ADD model raises the and invariant mass
distributions at high scales of and invariant mass; in the RS model
resonant peaks appear after the SM contribution dies away; the SM and the MSSM
distributions drop rapidly at those high scales; in the ADD and the RS models
the rapidity distributions congregate more around the center. It is concluded
that various distributions of the Higgs pair production at the LHC with
restrictive kinematic cuts would provide one of the most robust signals for the
extra dimensional effects.Comment: Revised version, 26 pages including 11 figures, ReVTe
Searching for Multijet Resonances at the LHC
Recently it was shown that there is a class of models in which colored vector
and scalar resonances can be copiously produced at the Tevatron with decays to
multijet final states, consistent with all experimental constraints and having
strong discovery potential. We investigate the collider phenomenology of TeV
scale colored resonances at the LHC and demonstrate a strong discovery
potential for the scalars with early data as well as the vectors with
additional statistics. We argue that the signal can be self-calibrating and
using this fact we propose a search strategy which we show to be robust to
systematic errors typically expected from Monte Carlo background estimates. We
model the resonances with a phenomenological Lagrangian that describes them as
bound states of colored vectorlike fermions due to new confining gauge
interactions. However, the phenomenological Lagrangian treatment is quite
general and can represent other scenarios of microscopic physics as well.Comment: 28 pages, 13 figures, pdflatex. Discussion of background expanded,
minor modifications made. Version to appear in JHE
Higgs-Boson Production Induced by Bottom Quarks
Bottom quark-induced processes are responsible for a large fraction of the
LHC discovery potential, in particular for supersymmetric Higgs bosons.
Recently, the discrepancy between exclusive and inclusive Higgs boson
production rates has been linked to the choice of an appropriate bottom
factorization scale. We investigate the process kinematics at hadron colliders
and show that it leads to a considerable decrease in the bottom factorization
scale. This effect is the missing piece needed to understand the corresponding
higher order results. Our results hold generally for charged and for neutral
Higgs boson production at the LHC as well as at the Tevatron. The situation is
different for single top quark production, where we find no sizeable
suppression of the factorization scale. Turning the argument around, we can
specify how large the collinear logarithms are, which can be resummed using the
bottom parton picture.Comment: 18 page
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