Weak Interaction Before the Standard Model

2018 ◽  
pp. 11-34
Author(s):  
Samoil Bilenky
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
The Standard Model

scholarly journals WHAT IS A MATTER PARTICLE?

2006 ◽  
Vol 15 (01) ◽  
pp. 259-272
Author(s):  
TSAN UNG CHAN
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Strong Interaction ◽  
Neutral Particle ◽  
Z Bosons ◽  
Baryon Number ◽  
Lepton Number ◽  
Neutral Particles ◽  
The Standard Model ◽  
The Stability

Positive baryon numbers (A>0) and positive lepton numbers (L>0) characterize matter particles while negative baryon numbers and negative lepton numbers characterize antimatter particles. Matter particles and antimatter particles belong to two distinct classes of particles. Matter neutral particles are particles characterized by both zero baryon number and zero lepton number. This third class of particles includes mesons formed by a quark and an antiquark pair (a pair of matter particle and antimatter particle) and bosons which are messengers of known interactions (photons for electromagnetism, W and Z bosons for the weak interaction, gluons for the strong interaction). The antiparticle of a matter particle belongs to the class of antimatter particles, the antiparticle of an antimatter particle belongs to the class of matter particles. The antiparticle of a matter neutral particle belongs to the same class of matter neutral particles. A truly neutral particle is a particle identical with its antiparticle; it belongs necessarily to the class of matter neutral particles. All known interactions of the Standard Model conserve baryon number and lepton number; matter cannot be created or destroyed via a reaction governed by these interactions. Conservation of baryon and lepton number parallels conservation of atoms in chemistry; the number of atoms of a particular species in the reactants must equal the number of those atoms in the products. These laws of conservation valid for interaction involving matter particles are indeed valid for any particles (matter particles characterized by positive numbers, antimatter particles characterized by negative numbers, and matter neutral particles characterized by zero). Interactions within the framework of the Standard Model which conserve both matter and charge at the microscopic level cannot explain the observed asymmetry of our Universe. The strong interaction was introduced to explain the stability of nuclei: there must exist a powerful force to compensate the electromagnetic force which tends to cause protons to fly apart. The weak interaction with laws of conservation different from electromagnetism and the strong interaction was postulated to explain beta decay. Our observed material and neutral universe would signify the existence of another interaction that did conserve charge but did not conserve matter.

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.

The physics of W ± and Z 0 particles

1986 ◽  
Vol 404 (1827) ◽  
pp. 189-211
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Theoretical Framework ◽  
Current Understanding ◽  
Electroweak Interactions ◽  
Decay Properties ◽  
The Standard Model

The standard model is a theoretical framework describing the behaviour of elementary quarks and leptons as a result of strong and electroweak interactions. Our current understanding of the production and decay properties of the W ± and Z 0 particles, the exchange bosons of the weak interaction, will be described and the striking agreement of these properties with predictions of the standard model will be emphasized.

scholarly journals Differences Between Two Weak Interaction Theories

2019 ◽  
pp. 1-9
Author(s):  
E. Comay
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Electroweak Theory ◽  
Interaction Theory ◽  
Quantum Theories ◽  
The Standard Model

This paper analyzes differences between theoretical elements of the Standard Model electroweak theory and corresponding properties of a dipole-dipole weak interaction theory. The analysis relies on a number of self-evident criteria that are valid for quantum theories. The results demonstrate the  existence of fundamental errors in the electroweak theory and the advantage of the dipole-dipole weak interaction theory.

scholarly journals DARK MATTER CANDIDATE FROM CONFORMALITY

2007 ◽  
Vol 22 (13) ◽  
pp. 931-937 ◽  
Author(s):  
P. H. FRAMPTON
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Cross Section ◽  
Weak Interaction ◽  
Gauge Theories ◽  
Dark Matter Candidate ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Relic Density ◽  
Baryonic Dark Matter

Abelian quiver gauge theories provide candidates for the conformality approach to physics beyond the standard model which possess novel cancellation mechanisms for quadratic divergences. A Z2 symmetry ( R parity) can be imposed and leads naturally to a dark matter candidate which is the Lightest Conformality Particle (LCP), a neutral spin-1 / 2 state with weak interaction annihilation cross-section, mass in the 100 GeV region and relic density of non-baryonic dark matter Ωdm which can be consistent with the observed value Ωdm≃0.24.

scholarly journals LEFT–RIGHT POLARIZATION ASYMMETRY OF THE WEAK INTERACTION MASS OF POLARIZED FERMIONS IN FLIGHT

2013 ◽  
Vol 28 (15) ◽  
pp. 1350059
Author(s):  
ZHI-QIANG SHI
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Weak Interaction ◽  
Inertial Frame ◽  
Weak Interactions ◽  
Polarization Asymmetry ◽  
Mass Asymmetry ◽  
Left Handed ◽  
The Standard Model ◽  
Important Significance

The left–right polarization-dependent asymmetry of the weak interaction mass is investigated. Based on the Standard Model (SM), the calculation shows that the weak interaction mass of left-handed polarized fermions is always greater than that of right-handed ones in flight with the same speed in any inertial frame. The weak interaction mass asymmetry might be very important to the investigation of neutrino mass and would have an important significance for understanding the chiral attribute of weak interactions.

Studies of the weak interaction in atomic systems: Towards measurements of atomic parity non-conservation in francium

2021 ◽  
Author(s):  
Gerald Gwinner ◽  
L A Orozco
Keyword(s):  
Stable Isotope ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Weak Interaction ◽  
Particle Physics ◽  
Hadron Collider ◽  
Low Energy ◽  
Atomic Systems ◽  
The Standard Model

Abstract Tests of the Standard Model of particle physics should be carried out over the widest possible range of energies. Here we present our plans and progress for an atomic parity non-conservation experiment using the heaviest alkali, francium (Z = 87), which has no stable isotope. Low-energy tests of this kind have sensitivity complementary to higher energy searches, e.g. at the Large Hadron Collider.

scholarly journals Leptonic decays of the tau lepton

2019 ◽  
Vol 212 ◽  
pp. 08004 ◽  
Author(s):  
Matteo Fael
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Tau Lepton ◽  
Decay Modes ◽  
Leptonic Decays ◽  
The Standard Model

In these proceedings we review the SM prediction for the tau leptonic decays, including the radiative $ (\tau \to \ell \lambda \nu \bar \nu ) $ and the five-body $ (\tau \to \ell \ell '\ell '\nu \bar \nu ) $ decay modes, which are among the most powerful tools to study precisely the structure of the weak interaction and to constrain possible contributions beyond the V–A coupling of the Standard Model.

A GENERATION MODEL OF COMPOSITE LEPTONS AND QUARKS

2005 ◽  
Vol 14 (08) ◽  
pp. 1151-1169 ◽  
Author(s):  
B. A. ROBSON
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Composite Model ◽  
Generation Model ◽  
New Model ◽  
Color Type ◽  
The Standard Model ◽  
Triplet Representation

A new composite model for leptons and quarks is presented. The model treats leptons and quarks as composites of three kinds of spin-½ particles (rishons), which belong to a fundamental triplet representation of a flavor SU (3) symmetry. A super-strong color-type force binds rishons together to form colorless leptons or quarks. Quarks display a valence property, which corresponds to the quark color of the Standard Model. Leptons have no valence property and are inert with respect to the super-strong color interaction. Both the strong color force and the weak interaction of the Standard Model are residual interactions of the super-strong color force in the new model.

scholarly journals ON FLAVOR CONSERVATION IN WEAK INTERACTION DECAYS INVOLVING MIXED NEUTRINOS

2010 ◽  
Vol 25 (22) ◽  
pp. 4179-4194 ◽  
Author(s):  
MASSIMO BLASONE ◽  
ANTONIO CAPOLUPO ◽  
CHUENG-RYONG JI ◽  
GIUSEPPE VITIELLO
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Standard Model ◽  
Weak Interaction ◽  
Tree Level ◽  
Quantum Field ◽  
Interaction Processes ◽  
Lepton Charge ◽  
The Standard Model ◽  
Short Time

In the context of quantum field theory (QFT), we compute the amplitudes of weak interaction processes such as W+ →e+ + νe and W+ →e+ + νμ by using different representations of flavor states for mixed neutrinos. Analyzing the short time limit of the above amplitudes, we find that the neutrino states defined in QFT as eigenstates of the flavor charges lead to results consistent with lepton charge conservation. On the contrary, the Pontecorvo flavor states produce a violation of lepton charge in the vertex, which is in contrast with what expected at tree level in the Standard Model.

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