Testing the standard model versus a composite structure of weak interactions in high precision experiments at LEP and SLC

1987 ◽  
Vol 291 ◽  
pp. 1-40 ◽  
Author(s):  
U. Baur ◽  
M. Lindner ◽  
K.H. Schwarzer
Keyword(s):  
Standard Model ◽  
High Precision ◽  
Composite Structure ◽  
Weak Interactions ◽  
The Standard Model ◽  
Model Versus

Electroweak Interactions and W, Z Boson Properties

2020 ◽  
Author(s):  
Maarten Boonekamp ◽  
Matthias Schott
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Top Quark ◽  
Quantum Electrodynamics ◽  
Weak Interactions ◽  
Higgs Field ◽  
Nuclear Research ◽  
Strong Interactions ◽  
Weak Boson ◽  
The Standard Model

With the huge success of quantum electrodynamics (QED) to describe electromagnetic interactions in nature, several attempts have been made to extend the concept of gauge theories to the other known fundamental interactions. It was realized in the late 1960s that electromagnetic and weak interactions can be described by a single unified gauge theory. In addition to the photon, the single mediator of the electromagnetic interaction, this theory predicted new, heavy particles responsible for the weak interaction, namely the W and the Z bosons. A scalar field, the Higgs field, was introduced to generate their mass. The discovery of the mediators of the weak interaction in 1983, at the European Center for Nuclear Research (CERN), marked a breakthrough in fundamental physics and opened the door to more precise tests of the Standard Model. Subsequent measurements of the weak boson properties allowed the mass of the top quark and of the Higgs Boson to be predicted before their discovery. Nowadays, these measurements are used to further probe the consistency of the Standard Model, and to place constrains on theories attempting to answer still open questions in physics, such as the presence of dark matter in the universe or unification of the electroweak and strong interactions with gravity.

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.

scholarly journals From old symmetries to new symmetries: Quarks, leptons and B-L

2014 ◽  
Vol 29 (29) ◽  
pp. 1430066 ◽  
Author(s):  
Rabindra N. Mohapatra
Keyword(s):  
Standard Model ◽  
Weak Interactions ◽  
Low Energy ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Recent Developments

The Baryon–Lepton difference (B-L) is increasingly emerging as a possible new symmetry of the weak interactions of quarks and leptons as a way to understand the small neutrino masses. There is the possibility that current and future searches at colliders and in low energy rare processes may provide evidence for this symmetry. This paper provides a brief overview of the early developments that led to B-L as a possible symmetry beyond the standard model, and also discusses some recent developments.

scholarly journals A TORSIONAL MODEL OF LEPTONS

2012 ◽  
Vol 27 (34) ◽  
pp. 1250199 ◽  
Author(s):  
LUCA FABBRI
Keyword(s):  
Standard Model ◽  
Bound States ◽  
Weak Interactions ◽  
Specific Mass ◽  
The Standard Model

Quite recently it was shown that torsion induces interactions among leptons that are identical to the weak interactions of leptons of the Weinberg Standard Model, if it is in terms of leptonic bound states that the bosonic sector is built; here we obtain the partially conserved axial currents showing that they are the same of the Standard Model, if the composite mediators have specific mass relationships: we show that their masses are indeed the measured ones, if reasonable approximations are taken.

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.

scholarly journals BOUND-STATE/ELEMENTARY-PARTICLE DUALITY IN THE HIGGS SECTOR AND THE CASE FOR AN EXCITED "HIGGS" WITHIN THE STANDARD MODEL

2013 ◽  
Vol 28 (28) ◽  
pp. 1350103 ◽  
Author(s):  
AXEL MAAS
Keyword(s):  
Elementary Particle ◽  
Standard Model ◽  
Cross Sections ◽  
Bound States ◽  
Weak Interactions ◽  
Higgs Sector ◽  
Bound State ◽  
Leading Order ◽  
Expectation Value ◽  
The Standard Model

Though being weakly interacting, QED can support bound states. In principle, this can be expected for the weak interactions in the Higgs sector as well. In fact, it has been argued long ago that there should be a duality between bound states and the elementary particles in this sector, at least in leading order in an expansion in the Higgs quantum fluctuations around its expectation value. Whether this remains true beyond the leading order is being investigated using lattice simulations, and support is found. This provides a natural interpretation of peaks in cross-sections as bound states. This would imply that (possibly very broad) resonances of Higgs and W and Z bound states could exist within the Standard Model.

The ALEPH experiment

1991 ◽  
Vol 336 (1642) ◽  
pp. 201-211 ◽  
Keyword(s):  
Standard Model ◽  
High Precision ◽  
Z Bosons ◽  
Higgs Mechanism ◽  
Theory Testing ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Physics Potential ◽  
The Standard Model ◽  
Very High

Alep detector must be designed to address the known physics potential of the accelerator and be sufficiently flexible to accommodate the unexpected. This was the foundation for the design of aleph. lep provides the opportunity to make the most sensitive tests of the Standard Model of electroweak interactions which will probably ever be possible. The first requirement of the detector must therefore be to ensure it has the capability to make these precise tests of the electro weak theory. Testing the Standard Model at lep will take place at the following two energies. 1 .At the Z peak ( lep 1 at a centre of mass energy ca. 90 GeV). At this energy the electron and positron annihilate to form real Z bosons. This enables the Z mass, width and couplings to leptons and quarks to be determined with very high precision. Annihilations with longitudinally polarized electron and positron beams will eventually allow additional stringent tests. 2. Above the WW threshold (lep 2at a centre of mass energy ca. 190 GeV). At this energy the emphasis will be on the charged gauge boson, its mass, its couplings to fermions and the non-abelian ZWW coupling. Investigation of longitudinal Ws, which result directly from the Higgs mechanism, will be possible. The detector must therefore be designed to handle the increased complexity and energies of interactions at lep 2 as well as those at the Z peak.

scholarly journals MEASUREMENT OF THE RATIO OF THE CHARGED KAON LEPTONIC DECAYS AT NA62

2014 ◽  
Vol 35 ◽  
pp. 1460436
Author(s):  
VENELIN KOZHUHAROV
Keyword(s):  
Data Analysis ◽  
Standard Model ◽  
Weak Interactions ◽  
New Physics ◽  
Charged Kaon ◽  
Kaon Decays ◽  
Leptonic Decays ◽  
Lepton Universality ◽  
Analysis Technique ◽  
The Standard Model

The ratio of the leptonic charged kaon decays RK = Γ(K± → e±ν)/Γ(K± → μ±ν) is sensitive to the structure of the weak interactions and can be precisely calculated within the Standard Model. Presence of New Physics can introduce a shift on its value of the order of a percent. The NA62 experiment at CERN SPS used data from a dedicated run in 2007 to perform a measurement of this ratio and probe the lepton universality. The data analysis technique and the final results are presented.

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