96 research outputs found
A Forward Branching Phase Space Generator for Hadron colliders
In this paper we develop a projective phase space generator appropriate for
hadron collider geometry. The generator integrates over bremsstrahlung events
which project back to a single, fixed Born event. The projection is dictated by
the experimental jet algorithm allowing for the forward branching phase space
generator to integrate out the jet masses and initial state radiation. When
integrating over the virtual and bremsstrahlung amplitudes this results in a
single K-factor, assigning an event probability to each Born event. This
K-factor is calculable as a perturbative expansion in the strong coupling
constant. One can build observables from the Born kinematics, giving identical
results to tradi- tional observables as long as the observable does not depend
on the infrared sensitive jet mass or initial state radiation.Comment: 16 pages, 10 figure
Anomalous Higgs boson couplings in vector boson fusion at the CERN LHC
Deviations from SM expectations in the Higgs sector can be parameterized by
an effective Lagrangian. The corresponding anomalous couplings have been
implemented in a Monte Carlo program for Higgs production in vector boson
fusion, at NLO QCD accuracy. It allows to study anomalous coupling effects for
production and decay of the Higgs boson. We analyze deviations allowed by LEP
data and study a new azimuthal angle variable which directly measures the
interference between CP-even, CP-odd and SM couplings.Comment: 15 pages, 8 figure
QCD corrections to vector boson fusion processes
NLO QCD corrections to H, W and Z production via vector boson fusion have
recently been calculated in the form of flexible parton level Monte Carlo
programs. This allows for the calculation of distributions and cross sections
with cuts at NLO accuracy. Some features of the calculation, as well as results
for the LHC, are reviewed.Comment: 1 style file, 1 latex file, 5 figures, Contribution to the
Proceedings of "Loops and Legs in Quantum Field Theory, 2004", Zinnowitz,
Usedom Island, Germany, April, 200
Next-to-leading order QCD corrections to Higgs boson production in association with a photon via weak-boson fusion at the LHC
Higgs boson production in association with a hard central photon and two
forward tagging jets is expected to provide valuable information on Higgs boson
couplings in a range where it is difficult to disentangle weak-boson fusion
processes from large QCD backgrounds. We present next-to-leading order QCD
corrections to Higgs production in association with a photon via weak-boson
fusion at a hadron collider in the form of a flexible parton-level Monte Carlo
program. The QCD corrections to integrated cross sections are found to be small
for experimentally relevant selection cuts, while the shape of kinematic
distributions can be distorted by up to 20% in some regions of phase space.
Residual scale uncertainties at next-to-leading order are at the few-percent
level.Comment: 17 pages, 7 figures, 1 tabl
Maximum Significance at the LHC and Higgs Decays to Muons
We present a new way to define and compute the maximum significance
achievable for signal and background processes at the LHC, using all available
phase space information. As an example, we show that a light Higgs boson
produced in weak--boson fusion with a subsequent decay into muons can be
extracted from the backgrounds. The method, aimed at phenomenological studies,
can be incorporated in parton--level event generators and accommodate
parametric descriptions of detector effects for selected observables.Comment: 7 pages, 2 figures, changes to wording and new references, published
versio
NLO Higgs boson production via vector-boson fusion matched with shower in POWHEG
We present a next-to-leading order calculation of Higgs boson production in
vector-boson fusion processes interfaced to shower Monte Carlo programs,
implemented according to the POWHEG method.Comment: 16 pages, 9 figures. A few references and a new figure adde
Collider Signatures of the N=3 Lee-Wick Standard Model
Inspired by the Lee-Wick higher-derivative approach to quantum field theory,
Grinstein, O'Connell, and Wise have illustrated the utility of introducing into
the Standard Model negative-norm states that cancel quadratic divergences in
loop diagrams, thus posing a potential resolution of the hierarchy problem.
Subsequent work has shown that consistency with electroweak precision
parameters requires many of the partner states to be too massive to be detected
at the LHC. We consider the phenomenology of a yet-higher derivative theory
that exhibits three poles in its bare propagators (hence N=3), whose states
alternate in norm. We examine the interference effects of W boson partners on
LHC scattering cross sections, and find that the N=3 LWSM already makes
verifiable predictions at 10 fb^(-1) of integrated luminosity.Comment: 15 pages, 4 PDF figures. Version accepted for publication by JHE
Release Note -- Vbfnlo-2.6.0
Vbfnlo is a flexible parton level Monte Carlo program for the simulation of
vector boson fusion (VBF), double and triple vector boson (plus jet) production
in hadronic collisions at next-to-leading order (NLO) in the strong coupling
constant, as well as Higgs boson plus two jet production via gluon fusion at
the one-loop level. This note briefly describes the main additional features
and processes that have been added in the new release -- Vbfnlo Version 2.6.0.
At NLO QCD diboson production (W\gamma, WZ, ZZ, Z\gamma and \gamma\gamma),
same-sign W pair production via vector boson fusion and the process
W\gamma\gamma j have been implemented (for which one-loop tensor integrals up
to six-point functions are included). In addition, gluon induced diboson
production can be studied separately at the leading order (one-loop) level. The
diboson processes WW, WZ and W\gamma can be run with anomalous gauge boson
couplings, and anomalous couplings between a Higgs and a pair of gauge bosons
is included in WW, ZZ, Z\gamma and \gamma\gamma diboson production. The code
has also been extended to include anomalous gauge boson couplings for single
vector boson production via VBF, and a spin-2 model has been implemented for
diboson pair production via vector boson fusion.Comment: 14 pages, 6 tables; new code available at
http://www-itp.particle.uni-karlsruhe.de/vbfnlo
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