109 research outputs found
Fiducial polarization observables in hadronic WZ production: A next-to-leading order QCD+EW study
We present a study at next-to-leading-order (NLO) of the process , where , at the
Large Hadron Collider. We include the full NLO QCD corrections and the NLO
electroweak (EW) corrections in the double-pole approximation. We define eight
fiducial polarization coefficients directly constructed from the
polar-azimuthal angular distribution of the decay leptons. These coefficients
depend strongly on the kinematical cuts on the transverse momentum or rapidity
of the individual leptons. Similarly, fiducial polarization fractions are also
defined and they can be directly related to the fiducial coefficients. We
perform a detailed analysis of the NLO QCD+EW fiducial polarization observables
including theoretical uncertainties stemming from the scale variation and
parton distribution function uncertainties, using the fiducial phase space
defined by the ATLAS and CMS experiments. We provide results in the helicity
coordinate system and in the Collins-Soper coordinate system, at a
center-of-mass energy of 13 TeV. The EW corrections are found to be important
in two of the angular coefficients related to the boson, irrespective of
the kinematical cuts or the coordinate system. Meanwhile, those EW corrections
are very small for the bosons.Comment: Substantial improvement after useful comments from the anonymous
referee: Numerical results for the EW corrections to the cross sections and
distributions shifted by -5 (-2)% for ATLAS (CMS) cuts after fixing a bug in
the momentum assignment in some cut and histogram routines; results for
polarization observables marginally affected, hence conclusions for them
unchanged; published versio
On the triplet anti-triplet symmetry in 3-3-1 models
We present a detailed discussion of the triplet anti-triplet symmetry in
3-3-1 models. The full set of conditions to realize this symmetry is provided,
which includes in particular the requirement that the two vacuum expectation
values of the two scalar triplets responsible for making the W and Z bosons
massive must be interchanged. We apply this new understanding to the
calculation of processes that have a Z-Z' mixing.Comment: 14 page
Polarisation at NLO in WZ production at the LHC
The pair production of a and a boson at the LHC is an important
process to study the triple-gauge boson couplings as well as to probe new
physics that could arise in the gauge sector. In particular the leptonic
channel is considered by ATLAS and CMS
collaborations. Polarisation observables can help pinning down new physics and
give information on the spin of the gauge bosons. Measuring them requires high
statistics as well as precise theoretical predictions. We define in this
contribution fiducial polarisation observables for the and bosons and
we present theoretical predictions in the Standard Model at next-to-leading
order (NLO) including QCD as well as NLO electroweak corrections, the latter in
the double-pole approximation. We also show that this approximation works
remarkably well for production at the LHC by comparing to the full
results.Comment: 6 pages, 2 figures, 2 tables. Contribution to the proceedings of the
54th Rencontres de Moriond, EW interactions and unified theory, March 16-23
2019, La Thuile, Ital
Full NLO massive gauge boson pair production at the LHC
Electroweak gauge boson pair production is a very important process at the
LHC as it probes the non-abelian structure of electroweak interactions and is a
background process for many searches. We present full next-to-leading order
predictions for the production cross sections and distributions of on-shell
massive gauge boson pair production in the Standard Model, including both QCD
and electroweak corrections. The hierarchy between the ZZ, WW and WZ channels,
observed in the transverse momentum distributions, will be analyzed. We will
also present a comparison with experimental data for the total cross sections
including a study of the theoretical uncertainties.Comment: 4 pages, 4 figures. Proceeding of the inaugural conference "Windows
on the Universe" (August 11-17, Quy Nhon, Vietnam) including updated results
compared to arXiv:1307.433
W-+ H+- production and CP asymmetry at the LHC
The dominant contributions to W-+ H+- production at the LHC are the
tree-level b anti-b annihilation and the gg fusion. We perform for the case of
the complex MSSM a complete calculation of the NLO EW corrections to the b
anti-b annihilation channel and a consistent combination with other
contributions including the standard and SUSY QCD corrections and the gg
fusion, with resummation of the leading radiative corrections to the
bottom-Higgs couplings and the neutral Higgs-boson propagators. We observe a
large CP-violating asymmetry, arising mainly from the gg channel.Comment: 33 pages, 21 figures, a few typos corrected, one reference adde
- …