167 research outputs found
One loop verification of SMEFT Ward Identities
We verify Standard Model Effective Field Theory Ward identities to one loop
order when background field gauge is used to quantize the theory. The results
we present lay the foundation of next to leading order automatic generation of
results in the SMEFT, in both the perturbative and non-perturbative expansion
using the geoSMEFT formalism, and background field gauge.Comment: 40 pages, 1 Figur
Exploring Extended Scalar Sectors with Di-Higgs Signals: A Higgs EFT Perspective
We consider extended scalar sectors of the Standard Model as
ultraviolet-complete motivations for studying the effective Higgs
self-interaction operators of the Standard Model effective field theory. We
investigate all motivated heavy scalar models which generate the dimension-6
effective operator, , at tree level and proceed to identify the full set
of tree-level dimension-six operators by integrating out the heavy scalars. Of
seven models which generate at tree level only two, quadruplets of
hypercharge and , generate only this operator. Next we perform
global fits to constrain relevant Wilson coefficients from the LHC single Higgs
measurements as well as the electroweak oblique parameters and . We find
that the parameter puts very strong constraints on the Wilson coefficient
of the operator in the triplet and quadruplet models, while the singlet
and doublet models could still have Higgs self-couplings which deviate
significantly from the standard model prediction. To determine the extent to
which the operator could be constrained, we study the dihiggs
signatures at the future 100 TeV collider and explore future sensitivity of
this operator. Projected onto the Higgs potential parameters of the extended
scalar sectors, with ab luminosity data we will be able to explore
the Higgs potential parameters in all seven models.Comment: 25 pages, 11 figures, 6 tables; version 3: match the JHEP published
versio
Hadron Collider Sensitivity to Fat Flavourful s for
We further investigate the case where new physics in the form of a massive
particle explains apparent measurements of lepton flavour
non-universality in decays. Hadron collider
sensitivities for direct production of such s have been previously
studied in the narrow width limit for a final state. Here, we
extend the analysis to sizeable decay widths and improve the sensitivity
estimate for the narrow width case. We estimate the sensitivities of the high
luminosity 14 TeV Large Hadron Collider (HL-LHC), a high energy 27 TeV LHC
(HE-LHC), as well as a potential 100 TeV future circular collider (FCC). The
HL-LHC has sensitivity to narrow resonances consistent with the
anomalies. In one of our simplified models the FCC could probe 23 TeV
particles with widths of up to 0.35 of their mass at 95\% confidence
level (CL). In another model, the HL-LHC and HE-LHC cover sizeable portions of
parameter space, but the whole of perturbative parameter space can be covered
by the FCC.Comment: 24 pages, 11 figures; v2 Reference
The Gauge-Higgs Legacy of the LHC Run II
We present a global analysis of the Higgs and electroweak sector based on LHC
Run II and electroweak precision observables. We show which measurements
provide the leading constraints on Higgs-related operators, and how the
achieved LHC precision makes it necessary to combine rate measurements with
electroweak precision observables. The SFitter framework allows us to include
kinematic distributions beyond pre-defined ATLAS and CMS observables,
independently study correlations, and avoid Gaussian assumptions for theory
uncertainties. These Run II results are a step towards a precision physics
program at the LHC, interpreted in terms of effective operators.Comment: 16 pages, 8 figures, comments adde
The Higgs width in the SMEFT
We calculate the total and partial inclusive Higgs widths at leading order in
the Standard Model Effective Field Theory (SMEFT). We report results
incorporating SMEFT corrections for two and four body Higgs decays through
vector currents in this limit. The narrow width approximation is avoided and
all phase space integrals are directly evaluated. We explain why the narrow
width approximation fails more significantly in the SMEFT compared to the SM,
despite the narrowness of the observed bosons in both
theories. Our results are presented in a manner that allows various input
parameter schemes to be used, and they allow the inclusive branching ratios and
decay widths of the Higgs to be numerically determined without a Monte Carlo
generation of phase space for each Wilson coefficient value chosen.Comment: 46 pages, 6 figures, 10 tables. Version published in JHE
Constraining anomalous Higgs interactions
The recently announced Higgs discovery marks the dawn of the direct probing
of the electroweak symmetry breaking sector. Sorting out the dynamics
responsible for electroweak symmetry breaking now requires probing the Higgs
interactions and searching for additional states connected to this sector. In
this work we analyze the constraints on Higgs couplings to the standard model
gauge bosons using the available data from Tevatron and LHC. We work in a
model--independent framework expressing the departure of the Higgs couplings to
gauge bosons by dimension--six operators. This allows for independent
modifications of its couplings to gluons, photons and weak gauge bosons while
still preserving the Standard Model (SM) gauge invariance. Our results indicate
that best overall agreement with data is obtained if the cross section of Higgs
production via gluon fusion is suppressed with respect to its SM value and the
Higgs branching ratio into two photons is enhanced, while keeping the
production and decays associated to couplings to weak gauge bosons close to
their SM prediction.Comment: v3: Added acknowledgment to FP7 ITN INVISIBLES (Marie Curie Actions
PITN-GA-2011-289442). Nothing else changed with respect to v
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