scholarly journals EWPD in the SMEFT to dimension eight

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Tyler Corbett ◽  
Andreas Helset ◽  
Adam Martin ◽  
Michael Trott
Keyword(s):  
Effective Field ◽  
Precision Data ◽  
Data Set ◽  
The Standard Model ◽  
Electroweak Precision ◽  
The Impact ◽  
First Time ◽  
Geometric Formulation ◽  
Electroweak Precision Data ◽  
Theory Error

Abstract We calculate the $$ \mathcal{O}\left({\left\langle {H}^{\dagger }H\right\rangle}^2/{\Lambda}^4\right) $$ O H † H 2 / Λ 4 corrections to LEP electroweak precision data using the geometric formulation of the Standard Model Effective Field Theory (SMEFT). We report our results in simple-to-use interpolation tables that allow the interpretation of this data set to dimension eight for the first time. We demonstrate the impact of these previously unknown terms in the case of a general analysis in the SMEFT, and also in the cases of two distinct models matched to dimension eight. Neglecting such dimension-eight corrections to LEP observables introduces a theoretical error in SMEFT studies. We report some preliminary studies defining such a theory error, explicitly demonstrating the effect of previously unknown dimension-eight SMEFT corrections on LEP observables.

scholarly journals Dimension-8 operators in the Standard Model Effective Field Theory

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Christopher W. Murphy
Keyword(s):  
Field Theory ◽  
Light Scattering ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Precision Data ◽  
Complete Basis ◽  
The Standard Model ◽  
Electroweak Precision ◽  
Electroweak Precision Data

Abstract We present a complete basis of dimension-8 operators in the Standard Model Effective Field Theory. Attention is paid to operators that vanish in the absence of flavor structure. The 44,807 operators are encoded in 1,031 Lagrangian terms. We also briefly discuss a few aspects of phenomenology involving dimension-8 operators, including light-by-light scattering and electroweak precision data.

scholarly journals CONSTRAINING NEW MODELS WITH PRECISION ELECTROWEAK DATA

2006 ◽  
Vol 21 (19n20) ◽  
pp. 4045-4070 ◽  
Author(s):  
MU-CHUN CHEN ◽  
SALLY DAWSON ◽  
TADAS KRUPOVNICKAS
Keyword(s):  
Top Quark ◽  
New Physics ◽  
Tree Level ◽  
Symmetric Model ◽  
Top Quark Mass ◽  
Precision Data ◽  
The Standard Model ◽  
The One ◽  
Electroweak Precision ◽  
Electroweak Precision Data

Electroweak precision data have been extensively used to constrain models containing physics beyond that of the Standard Model (SM). When the model contains Higgs scalars in representations other than singlets or doublets, and hence ρ≠1 at tree-level, a correct renormalization scheme requires more inputs than the three commonly used for the SM case. In such cases, the one-loop electroweak results cannot be split into a SM contribution plus a piece which vanishes as the scale of new physics becomes much larger than MW. We illustrate our results by presenting the dependence of MW on the top-quark mass in a model with a Higgs triplet and in the SU (2)L × SU (2)R left–right symmetric model. In these models, the allowed range for the lightest neutral Higgs mass can be as large as a few TeV.

scholarly journals THE TOP PRIORITY: PRECISION ELECTROWEAK PHYSICS FROM LOW TO HIGH ENERGY

2004 ◽  
Vol 19 (06) ◽  
pp. 808-820 ◽  
Author(s):  
P. GAMBINO
Keyword(s):  
Precise Measurement ◽  
High Energy ◽  
New Physics ◽  
Precision Data ◽  
The Standard Model ◽  
B Quark ◽  
Electroweak Precision ◽  
Top Mass ◽  
Electroweak Precision Data

Overall, the Standard Model describes electroweak precision data rather well. There are however a few areas of tension (charged current universality, NuTeV, (g-2)μ, b quark asymmetries), which I review critically, emphasizing recent theoretical and experimental progress. I also summarize what precision data tell us about the Higgs boson and new physics scenarios. In this context, the role of a precise measurement of the top mass is crucial.

scholarly journals B anomalies under the lens of electroweak precision

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Lina Alasfar ◽  
Aleksandr Azatov ◽  
Jorge de Blas ◽  
Ayan Paul ◽  
Mauro Valli
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Theoretical Interpretation ◽  
Precision Data ◽  
Lepton Universality ◽  
The Standard Model ◽  
Flavour Violation ◽  
Electroweak Precision

Abstract The measurements carried out at LEP and SLC projected us into the precision era of electroweak physics. This has also been relevant in the theoretical interpretation of LHCb and Belle measurements of rare B semileptonic decays, paving the road for new physics with the inference of lepton universality violation in $$ {R}_{K^{\left(\ast \right)}} $$ R K ∗ ratios. The simplest explanation of these flavour anomalies — sizeable one-loop contributions respecting Minimal Flavour Violation — is currently disfavoured by electroweak precision data. In this work, we discuss how to completely relieve the present tension between electroweak constraints and one-loop minimal flavour violating solutions to $$ {R}_{K^{\left(\ast \right)}} $$ R K ∗ . We determine the correlations in the Standard Model Effective Field Theory that highlight the existence of such a possibility. Then, we consider minimal extensions of the Standard Model where our effective-field-theory picture can be realized. We discuss how these solutions to b → sℓℓ anomalies, respecting electroweak precision and without any new source of flavour violation, may point to the existence of a Z′ boson at around the TeV scale, within the discovery potential of LHC, or to leptoquark scenarios.

scholarly journals EFT diagrammatica: UV roots of the CP-conserving SMEFT

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Supratim Das Bakshi ◽  
Joydeep Chakrabortty ◽  
Suraj Prakash ◽  
Shakeel Ur Rahaman ◽  
Michael Spannowsky
Keyword(s):  
Standard Model ◽  
Building Blocks ◽  
New Physics ◽  
Effective Field ◽  
Effective Operator ◽  
Physics Beyond Standard Model ◽  
The Standard Model ◽  
A Chain ◽  
The Impact ◽  
First Time

Abstract The Standard Model Effective Field Theory (SMEFT) is an established theoretical framework that parametrises the impact a UV theory has on low-energy observables. Such parametrization is achieved by studying the interactions of SM fields encapsulated within higher mass dimensional (≥ 5) operators. Through judicious employment of the tools of EFTs, SMEFT has become a source of new predictions as well as a platform for conducting a coherent comparison of new physics (beyond Standard Model) scenarios. We, for the first time, are proposing a diagrammatic approach to establish selection criteria for the allowed heavy field representations corresponding to each SMEFT operator. We have elucidated the links of a chain connecting specific CP conserving dimension-6 SMEFT operators with unique sets of heavy field representations. The contact interactions representing each effective operator have been unfolded into tree- and (or) one-loop-level diagrams to reveal unique embeddings of heavy fields within them. For each case, the renormalizable vertices of a UV model serve as the building blocks for all possible unfolded diagrams. Based on this, we have laid the groundwork to construct observable-driven new physics models. This in turn also prevents us from making redundant analyses of similar models. While we have taken a predominantly minimalistic approach, we have also highlighted the necessity for non-minimal interactions for certain operators.

scholarly journals The one-loop tadpole in the geoSMEFT

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Tyler Corbett
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Power Counting ◽  
Leading Order ◽  
The Standard Model ◽  
The One ◽  
Near Future ◽  
Geometric Formulation

Making use of the geometric formulation of the Standard Model Effective Field Theory we calculate the one-loop tadpole diagrams to all orders in the Standard Model Effective Field Theory power counting. This work represents the first calculation of a one-loop amplitude beyond leading order in the Standard Model Effective Field Theory, and discusses the potential to extend this methodology to perform similar calculations of observables in the near future.

scholarly journals Extra generations and discrepancies of electroweak precision data

2002 ◽  
Vol 529 (1-2) ◽  
pp. 111-116 ◽  
Author(s):  
V.A. Novikov ◽  
L.B. Okun ◽  
A.N. Rozanov ◽  
M.I. Vysotsky
Keyword(s):  
Precision Data ◽  
Electroweak Precision ◽  
Electroweak Precision Data

First Determination of the Proton's Weak Charge

2015 ◽  
Vol 8 (3) ◽  
Author(s):  
Shelley A. Page
Keyword(s):  
Standard Model ◽  
High Precision ◽  
Standard Model Prediction ◽  
Data Set ◽  
Weak Charge ◽  
Newport News ◽  
The Standard Model ◽  
First Results ◽  
First Time

The weak charge of the proton has been determined for the first time via a high precision electron-proton scattering experiment, Qweak, carried out at Jefferson Laboratory (JLab) in Newport News, USA. The weak charge is a basic property in subatomic physics, analogous to electric charge. The Standard Model makes a prediction for the weak charges of protons and other particles. First results described here are based on an initial 4% of the data set reported in 20131, with the ultimate goal of the experiment being a high precision Standard Model test conducted with the full Qweak data set. These initial results are consistent with the Standard Model prediction; they serve as an important first determination of the proton’s weak charge and a proof of principle that the ultimate goals are within reach.

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