53 research outputs found

### QCD corrections to hadronic WWZ production with leptonic decays

Multi-lepton signatures appear in many new physics searches at the Large
Hadron Collider. We here consider WWZ production with subsequent leptonic decay
of the three vector bosons as a SM source of multi-lepton events. We have
calculated the next-to-leading order QCD corrections for the full $p p\to 6$
lepton production cross sections in hadronic collisions. Results have been
implemented in the form of a flexible parton-level Monte-Carlo program which
allows to calculate the QCD corrections for arbitrary distributions and
acceptance cuts.Comment: 11 pages, 4 figures, version published in physics letters

### 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

### NLO QCD corrections to W+W- gamma and Z Z gamma production with leptonic decays

The computation of the NLO QCD corrections to the cross sections for W+W-
gamma and ZZgamma production in hadronic collisions is presented. We consider
the case of a real photon in the final state, but include full leptonic decays
of the W and Z bosons. Numerical results for the LHC and the Tevatron are
obtained through a fully flexible parton level Monte Carlo based on the
structure of the VBFNLO program, allowing an easy implementation of arbitrary
cuts and distributions. We show the dependence on scale variations of the
integrated cross sections and provide evidence that NLO QCD corrections
strongly modify the LO predictions for observables at the LHC both in magnitude
and in shape

### NLO QCD corrections to processes with multiple electroweak bosons

The VBFNLO program package is a collection of Monte Carlo programs for the
calculation of NLO QCD corrections to vector boson fusion cross sections,
double and triple vector boson production, or the production of two electroweak
bosons in association with an additional jet. An overview is given of the
processes and features implemented in VBFNLO. WWgamma and Wgamma jet production
are discussed as examples.Comment: 6 pages, 3 figures; talk given at RADCOR 2009 - 9th International
Symposium on Radiative Corrections (Applications of Quantum Field Theory to
Phenomenology), October 25 - 30 2009, Ascona, Switzerlan

### Monte Carlo studies of the jet activity in Higgs + 2 jet events

Tree-level studies have shown in the past that kinematical correlations
between the two jets in Higgs+2-jet events are direct probes of the Higgs
couplings, e.g. of their CP nature. In this paper we explore the impact of
higher-order corrections on the azimuthal angle correlation of the two leading
jets and on the rapidity distribution of extra jets. Our study includes
matrix-element and shower MC effects, for the two leading sources of Higgs plus
two jet events at the CERN LHC, namely vector-boson and gluon fusion. We show
that the discriminating features present in the previous leading-order matrix
element studies survive.Comment: 12 pages, 10 figures. Version to appear on JHEP. Figs. 5-8 replaced
with colour version

### Dominant next-to-leading order QCD corrections to Higgs plus three jet production in vector-boson fusion

We present the calculation of the dominant next to leading order QCD
corrections to Higgs boson production in association with three jets via vector
boson fusion in the form of a NLO parton-level Monte Carlo program. QCD
corrections to integrated cross sections are modest, while the shapes of some
kinematical distributions change appreciably at NLO. Scale uncertainties are
shown to be reduced at NLO for the total cross section and for distributions.
We consider a central jet veto at the LHC and analyze the veto probability for
typical vector boson fusion cuts. Scale uncertainties of the veto probability
are sufficiently small at NLO for precise Higgs coupling measurements at the
LHC.Comment: 40 pages, 17 figures, 2 tables, published versio

### Jet angular correlation in vector-boson fusion processes at hadron colliders

Higgs boson and massive-graviton productions in association with two jets via
vector-boson fusion (VBF) processes and their decays into a vector-boson pair
at hadron colliders are studied. They include scalar and tensor boson
production processes via weak-boson fusion in quark-quark collisions, gluon
fusion in quark-quark, quark-gluon and gluon-gluon collisions, as well as their
decays into a pair of weak bosons or virtual gluons which subsequently decay
into $\ell\bar\ell$, $q\bar q$ or $gg$. We give the helicity amplitudes
explicitly for all the VBF subprocesses, and show that the VBF amplitudes
dominate the exact matrix elements not only for the weak-boson fusion processes
but also for all the gluon fusion processes when appropriate selection cuts are
applied, such as a large rapidity separation between two jets and a slicing cut
for the transverse momenta of the jets. We also show that our off-shell
vector-boson current amplitudes reduce to the standard quark and gluon
splitting amplitudes with appropriate gluon-polarization phases in the
collinear limit. Nontrivial azimuthal angle correlations of the jets in the
production and in the decay of massive spin-0 and -2 bosons are manifestly
expressed as the quantum interference among different helicity states of the
intermediate vector-bosons. Those correlations reflect the spin and the CP
nature of the Higgs bosons and the massive gravitons.Comment: 47 pages, 7 figures, 10 tables; references added, version to appear
in JHE

### 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

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