79 research outputs found
CP-violating Higgs boson production in association with three jets via gluon fusion
In these proceedings, we present results for Higgs production at the LHC via
gluon fusion with triple real emission corrections and the validity range of
the heavy-top effective theory approximation for this process. For a general
CP-violating Higgs boson, we show that bottom-quark loop corrections in
combination with large values of significantly distort
differential distributions.Comment: 7 pages, 7 figures. To appear in the proceedings of Conference:
C14-07-0
Higgs boson production in association with three jets via gluon fusion at the LHC: Gluonic contributions
Higgs production in association with three jets via gluon fusion (GF) is an
important channel for the measurement of the CP-properties of the Higgs
particle at the LHC. In this letter, we go beyond the heavy top effective
theory approximation and include at LO the full mass dependence of the top- and
bottom-quark contributions. We consider the dominant sub-channel gg -> H ggg
which involves the manipulation of massive rank-5 hexagon integrals.
Furthermore, we present results for several differential distributions and show
deviations from the effective theory as large as 100% at high pT for light
Higgs masses.Comment: 5 pages, 4 figure
ZZ production at high transverse momenta beyond NLO QCD
We study the production of the four-lepton final state ,
predominantly produced by a pair of electroweak Z bosons, ZZ. Using the LoopSim
method, we merge NLO QCD results for ZZ and ZZ+jet and obtain approximate NNLO
predictions for ZZ production. The exact gluon-fusion loop-squared contribution
to the ZZ process is also included. On top of that, we add to our merged sample
the gluon-fusion ZZ+jet contributions from the gluon-gluon channel, which is
formally of N^3LO and provides approximate results at NLO for the gluon-fusion
mechanism. The predictions are obtained with the VBFNLO package and include the
leptonic decays of the Z bosons with all off-shell and spin-correlation
effects, as well as virtual photon contributions. We compare our predictions
with existing results for the total inclusive cross section at NNLO and find a
very good agreement. Then, we present results for differential distributions
for two experimental setups, one used in searches for anomalous triple gauge
boson couplings, the other in Higgs analyses in the four charged-lepton final
state channel. We find that the approximate NNLO corrections are large,
reaching up to 20% at high transverse momentum of the Z boson or the leading
lepton, and are not covered by the NLO scale uncertainties. Distributions of
the four-lepton invariant mass are, however, stable with respect to QCD
corrections at this order.Comment: 21 pages, 2 tables, 9 figure
Precise predictions for (non-standard) W+photon+jet production
We report on a detailed investigation of the next-to-leading order (NLO) QCD
corrections to +jet production at the Tevatron and the LHC using a
fully-flexible parton-level Monte Carlo program. We include the full leptonic
decay of the , taking into account all off-shell and finite width effects,
as well as non-standard couplings. We find particularly sizable
corrections for the currently allowed parameter range of anomalous couplings
imposed by LEP data. In total the NLO differential distributions reveal a
substantial phase space dependence of the corrections, leaving considerable
sensitivity to anomalous couplings beyond scale uncertainty at large momentum
transfers in the anomalous vertex.Comment: 22 pages, 14 figures, 2 tables, published versio
ZA production in vector-boson scattering at next-to-leading order QCD
Cross sections and differential distributions for ZA production in
association with two jets via vector boson fusion are presented at
next-to-leading order in QCD. The leptonic decays of the Z boson with full
off-shell effects and spin correlations are taken into account. The
uncertainties due to different scale choices and pdf sets are studied.
Furthermore, we analyze the effect of including anomalous quartic gauge
couplings at NLO QCD.Comment: 10 pages, 11 figure
Fit to the Bjorken, Ellis-Jaffe and Gross-Llewellyn-Smith sum rules in a renormalon based approach
We study the large order behaviour in perturbation theory of the Bjorken,
Ellis-Jaffe and Gross-Llewellyn-Smith sum rules. In particular, we consider
their first infrared renormalons, for which we obtain their analytic structure
with logarithmic accuracy and also an approximate determination of their
normalization constant. Estimates of higher order terms of the perturbative
series are given. The Renormalon subtracted scheme is worked out for these
observables and compared with experimental data. Overall, good agreement with
experiment is found. This allows us to obtain {\hat a}_0 and some higher-twist
non-perturbative constants from experiment: {\hat a}_0=0.141\pm 0.089;
f_{3,RS}(1 GeV)=-0.124^{+0.137}_{-0.142} GeV^2.Comment: 23 pages, 18 figures, one reference added, journal versio
WZ production in association with two jets at NLO in QCD
We report on the calculation of production with leptonic decays
at hadron-hadron colliders at next-to-leading order in QCD. These processes are
important both to test the quartic gauge couplings of the Standard Model and
because they constitute relevant backgrounds to beyond standard model physics
searches. Our results show that the next-to-leading order corrections reduce
significantly the scale uncertainties and have a non-trivial phase space
dependence.Comment: 4 pages, 5 figure
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