scholarly journals Experimental Tests of the Standard Model of Weak Interactions

2010 ◽  
Author(s):  
Dalibor ZAKOUCKY
Keyword(s):  
Standard Model ◽  
Weak Interactions ◽  
Experimental Tests ◽  
The Standard Model

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.

PRECISE TESTS OF e-μ UNIVERSALITY

1992 ◽  
Vol 07 (36) ◽  
pp. 3357-3364 ◽  
Author(s):  
TOSHIO NUMAO
Keyword(s):  
Standard Model ◽  
Weak Interactions ◽  
Branching Ratio ◽  
Experimental Tests ◽  
Model Calculations ◽  
The Status

The status of experimental tests of electron-muon universality in weak interactions is reviewed. The average of the new measurements of the π+→e+ν branching ratio, R ave =Γ(π→eν+π→eνγ)/Γ(π→μν+π→μνγ)=(1.2312±0.0037)×10−4, is consistent with standard model calculations R th =(1.234±0.001)×10−4 and confirms the hypothesis of electron-muon universality at the 0.2% level.

scholarly journals Consistency of matter models with asymptotically safe quantum gravity

2015 ◽  
Vol 93 (9) ◽  
pp. 988-994 ◽  
Author(s):  
Pietro Donà ◽  
Astrid Eichhorn ◽  
Roberto Percacci
Keyword(s):  
Renormalization Group ◽  
Standard Model ◽  
Quantum Gravity ◽  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Matter Content ◽  
Asymptotic Safety ◽  
The Standard Model ◽  
Renormalization Group Flows ◽  
Matter Fields

We discuss the compatibility of quantum gravity with dynamical matter degrees of freedom. Specifically, we present bounds we obtained in Donà et al. (Phys. Rev. D, 89, 084035 (2014) doi:10.1103/PhysRevD.89.084035 ) on the allowed number and type of matter fields within asymptotically safe quantum gravity. As a novel result, we show bounds on the allowed number of spin-3/2 (Rarita–Schwinger) fields (e.g., the gravitino). These bounds, obtained within truncated renormalization group flows, indicate the compatibility of asymptotic safety with the matter fields of the standard model. Further, they suggest that extensions of the matter content of the standard model are severely restricted in asymptotic safety. This means that searches for new particles at colliders could provide experimental tests for this particular approach to quantum gravity.

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 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.

CP Violation

2019 ◽  
pp. 295-312
Author(s):  
Michael E. Peskin
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
B Meson ◽  
Experimental Tests ◽  
K Meson ◽  
Neutral B Meson ◽  
The Standard Model ◽  
T Violation

This chapter describes particle reactions that violate CP and T symmetry, the decay of the neutral K meson and the neutral B meson. It presents the Kobayashi-Maskawa model that explains how the Standard Model can provide a theory of CP and T violation and describes experimental tests of that model.

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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