scholarly journals The Gauge-Higgs legacy of the LHC run II

2019 ◽  
Vol 6 (6) ◽  
Author(s):  
Anke Biekoetter ◽  
Tyler Corbett ◽  
Tilman Plehn
Keyword(s):  
Global Analysis ◽  
Physics Program ◽  
Combine Rate ◽  
Electroweak Sector ◽  
Precision Observables ◽  
Electroweak Precision ◽  
Effective Operators

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.

scholarly journals EFFECTIVE THEORIES AND ELECTROWEAK PRECISION CONSTRAINTS

2008 ◽  
Vol 23 (18) ◽  
pp. 2653-2685 ◽  
Author(s):  
ZHENYU HAN
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Effective Theory ◽  
Theory Method ◽  
The Standard Model ◽  
Precision Observables ◽  
Electroweak Precision ◽  
Effective Theories ◽  
Effective Operators

This is a pedagogical and self-contained review on obtaining electroweak precision constraints on TeV scale new physics using the effective theory method. We identify a set of relevant effective operators in the Standard Model and calculate from them corrections to all major electroweak precision observables. The corrections are compared with data to put constraints on the effective operators. Various approaches and applications in the literature are reviewed.

scholarly journals Global analysis of leptophilic Z′ bosons

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Andrzej J. Buras ◽  
Andreas Crivellin ◽  
Fiona Kirk ◽  
Claudio Andrea Manzari ◽  
Marc Montull
Keyword(s):  
Global Analysis ◽  
Magnetic Moments ◽  
Z Bosons ◽  
Left Handed ◽  
The Standard Model ◽  
Global Fit ◽  
Charged Leptons ◽  
Precision Observables ◽  
Electroweak Precision ◽  
Additional Constraints

Abstract New neutral heavy gauge bosons (Z′) are predicted within many extensions of the Standard Model. While in case they couple to quarks the LHC bounds are very stringent, leptophilic Z′ bosons (even with sizable couplings) can be much lighter and therefore lead to interesting quantum effects in precision observables (like (g − 2)μ) and generate flavour violating decays of charged leptons. In particular, $$ \mathrm{\ell}\to \mathrm{\ell}^{\prime }v\overline{v} $$ ℓ → ℓ ′ v v ¯ decays, anomalous magnetic moments of charged leptons, ℓ → ℓ′γ and ℓ → 3ℓ′ decays place stringent limits on leptophilic Z′ bosons. Furthermore, in case of mixing Z′ with the SM Z, Z pole observables are affected. In light of these many observables we perform a global fit to leptophilic Z′ models with the main goal of finding the bounds for the Z′ couplings to leptons. To this end we consider a number of scenarios for these couplings. While in generic scenarios correlations are weak, this changes once additional constraints on the couplings are imposed. In particular, if one considers an Lμ− Lτ symmetry broken only by left-handed rotations, or considers the case of τ − μ couplings only. In the latter setup, on can explain the (g − 2)μ anomaly and the hint for lepton flavour universality violation in $$ \tau \to \mu v\overline{v}/\tau \to ev\overline{v} $$ τ → μv v ¯ / τ → ev v ¯ without violating bounds from electroweak precision observables.

scholarly journals Suppressing electroweak precision observables in 5D warped models

2011 ◽  
Vol 2011 (5) ◽  
Author(s):  
Joan A. Cabrer ◽  
Gero von Gersdorff ◽  
Mariano Quirós
Keyword(s):  
Precision Observables ◽  
Electroweak Precision

scholarly journals Constraining the gauge and scalar sectors of the doublet left-right symmetric model

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Véronique Bernard ◽  
Sébastien Descotes-Genon ◽  
Luiz Vale Silva
Keyword(s):  
Symmetry Breaking ◽  
Electroweak Symmetry Breaking ◽  
Symmetric Model ◽  
Electroweak Symmetry ◽  
Gauge Bosons ◽  
Spontaneous Breakdown ◽  
The Standard Model ◽  
Low Energies ◽  
Precision Observables ◽  
Electroweak Precision

Abstract We consider a left-right symmetric extension of the Standard Model where the spontaneous breakdown of the left-right symmetry is triggered by doublets. The electroweak ρ parameter is protected from large corrections in this Doublet Left-Right Model (DLRM), contrary to the triplet case. This allows in principle for more diverse patterns of symmetry breaking. We consider several constraints on the gauge and scalar sectors of DLRM: the unitarity of scattering processes involving gauge bosons with longitudinal polarisations, the radiative corrections to the muon ∆r parameter and the electroweak precision observables measured at the Z pole and at low energies. Combining these constraints within the frequentist CKMfitter approach, we see that the fit pushes the scale of left-right symmetry breaking up to a few TeV, while favouring an electroweak symmetry breaking triggered not only by the SU(2)L×SU(2)R bi-doublet, which is the case most commonly considered in the literature, but also by the SU(2)L doublet.

scholarly journals Electroweak precision observables and the unhiggs

2009 ◽  
Vol 2009 (12) ◽  
pp. 061-061 ◽  
Author(s):  
Adam Falkowski ◽  
Manuel Pérez-Victoria
Keyword(s):  
Precision Observables ◽  
Electroweak Precision

scholarly journals Supersymmetric Contributions to Electroweak Precision Observables: QCD Corrections

1997 ◽  
Vol 78 (19) ◽  
pp. 3626-3629 ◽  
Author(s):  
A. Djouadi ◽  
P. Gambino ◽  
S. Heinemeyer ◽  
W. Hollik ◽  
C. Jünger ◽  
...  
Keyword(s):  
Precision Observables ◽  
Electroweak Precision

scholarly journals Leading QCD corrections to scalar quark contributions to electroweak precision observables

1998 ◽  
Vol 57 (7) ◽  
pp. 4179-4196 ◽  
Author(s):  
A. Djouadi ◽  
P. Gambino ◽  
S. Heinemeyer ◽  
W. Hollik ◽  
C. Jünger ◽  
...  
Keyword(s):  
Scalar Quark ◽  
Precision Observables ◽  
Electroweak Precision

scholarly journals Future Prospects of di-jet Production Constraining Δg(x) at Low x in Polarized p + p Collisions at RHIC

2015 ◽  
Vol 37 ◽  
pp. 1560068
Author(s):  
Bernd Surrow
Keyword(s):  
Global Analysis ◽  
Star Collaboration ◽  
High Energy ◽  
Precise Determination ◽  
Proton Spin ◽  
Gluon Polarization ◽  
Spin Physics ◽  
Jet Production ◽  
Physics Program ◽  
Low X

One of the main objectives of the high-energy spin physics program at RHIC at BNL is the precise determination of the polarized gluon distribution function, Δg(x). Polarized [Formula: see text] collisions at [Formula: see text] GeV and at [Formula: see text] GeV at RHIC provide an unique way to probe the proton spin structure. Inclusive measurements, such as inclusive jet and hadron production, have so far been the prime focus of various results at [Formula: see text] GeV constraining Δg(x) for 0.05 < x < 0.2. A recent global analysis provides for the first time evidence of a non-zero value of the gluon polarization [Formula: see text]. First results of di-jet production at [Formula: see text] GeV by the STAR collaboration will allow a better constraint of the underlying event kinematics. Extending the current program to smaller values of x is a key goal for the future high-energy spin physics program at RHIC. Forward di-jet production measurements at STAR beyond the current acceptance from -1 < η < +2 to +2.5 < η < +4, in particular those carried out at [Formula: see text] GeV, provides access to low x values at the level of 10-3 where current uncertainties of Δg(x) remain very large. Those measurements will eventually be complemented by a future Electron-Ion Collider facility probing Δg(x) in polarized [Formula: see text] collisions.

scholarly journals Theory requirements for SM Higgs and EW precision physics at the FCC-ee

2021 ◽  
Vol 136 (9) ◽  
Author(s):  
S. Heinemeyer ◽  
S. Jadach ◽  
J. Reuter
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
High Precision ◽  
Boson Mass ◽  
Experimental Measurements ◽  
Mixing Angle ◽  
The Standard Model ◽  
The Status ◽  
Precision Observables ◽  
Electroweak Precision

AbstractHigh-precision experimental measurements of the properties of the Higgs boson at $$\sim 125$$ ∼ 125  GeV as well as electroweak precision observables such as the W-boson mass or the effective weak leptonic mixing angle are expected at future $$e^+e^-$$ e + e - colliders such as the FCC-ee. This high anticipated precision has to be matched with theory predictions for the measured quantities at the same level of accuracy. We briefly summarize the status of these predictions within the standard model and of the tools that are used for their determination. We outline how the theory predictions will have to be improved in order to reach the required accuracy, and also comment on the simulation frameworks for the Higgs and EW precision program.

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