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.

scholarly journals Testing the mechanism of lepton compositeness

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Vincenzo Afferrante ◽  
Axel Maas ◽  
René Sondenheimer ◽  
Pascal Törek
Keyword(s):  
Gauge Theory ◽  
Standard Model ◽  
Gauge Invariance ◽  
Bound States ◽  
Lattice Gauge Theory ◽  
Higgs Field ◽  
Left Handed ◽  
Lattice Gauge ◽  
The Standard Model ◽  
Weyl Fermions

Strict gauge invariance requires that physical left-handed leptons are actually bound states of the elementary left-handed lepton doublet and the Higgs field within the standard model. That they nonetheless behave almost like pure elementary particles is explained by the Fr"ohlich-Morchio-Strocchi mechanism. Using lattice gauge theory, we test and confirm this mechanism for fermions. Though, due to the current inaccessibility of non-Abelian gauged Weyl fermions on the lattice, a model which contains vectorial leptons but which obeys all other relevant symmetries has been simulated.

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.

Lattice QCD Results and Prospects

2003 ◽  
Vol 18 (supp01) ◽  
pp. 1-26
Author(s):  
Richard Kenway
Keyword(s):  
Standard Model ◽  
Lattice Qcd ◽  
Strong Interaction ◽  
Bound States ◽  
Leading Edge ◽  
Beyond The Standard Model ◽  
Quark Masses ◽  
The Standard Model ◽  
Quark Flavour ◽  
Computationally Intensive

In the Standard Model, quarks and gluons are permanently confined by the strong interaction into hadronic bound states. The values of the quark masses and the strengths of the decays of one quark flavour into another cannot be measured directly, but must be deduced from experiments on hadrons. This requires calculations of the strong-interaction effects within the bound states, which are only possible using numerical simulations of lattice QCD. These are computationally intensive and, for the past twenty years, have exploited leading-edge computing technology. In conjunction with experimental data from B Factories, over the next few years, lattice QCD may provide clues to physics beyond the Standard Model. These lectures provide a non-technical introduction to lattice QCD, some of the recent results, QCD computers, and the future prospects.

scholarly journals Quantum stabilization of cosmic strings

2015 ◽  
Vol 30 (27) ◽  
pp. 1530022 ◽  
Author(s):  
H. Weigel ◽  
M. Quandt ◽  
N. Graham
Keyword(s):  
Standard Model ◽  
Top Quark ◽  
Cosmic String ◽  
Bound States ◽  
Degrees Of Freedom ◽  
Energy Levels ◽  
Binding Energies ◽  
Fermion Mass ◽  
The Standard Model ◽  
A Charge

In the standard model, stabilization of a classically unstable cosmic string may occur through the quantum fluctuations of a heavy fermion doublet. We review numerical results from a semiclassical expansion in a reduced version of the standard model. In this expansion, the leading quantum corrections emerge at one loop level for many internal degrees of freedom. The resulting vacuum polarization energy and the binding energies of occupied fermion energy levels are of the same order, and must therefore be treated on equal footing. Populating these bound states lowers the total energy compared to the same number of free fermions and assigns a charge to the string. Charged strings are already stabilized for a fermion mass only somewhat larger than the top quark mass. Though obtained in a reduced version, these results suggest that neither extraordinarily large fermion masses nor unrealistic couplings are required to bind a cosmic string in the standard model. Furthermore, we also review results for a quantum stabilization mechanism that prevents closed Nielsen–Olesen-type strings from collapsing.

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 Collider signatures of coannihilating dark matter in light of the B-physics anomalies

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Michael J. Baker ◽  
Darius A. Faroughy ◽  
Sokratis Trifinopoulos
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Bound States ◽  
B Physics ◽  
Search Strategy ◽  
Dark Matter Candidate ◽  
Final States ◽  
Dark Sector ◽  
Decay Modes ◽  
The Standard Model

Abstract Motivated by UV explanations of the B-physics anomalies, we study a dark sector containing a Majorana dark matter candidate and a coloured coannihilation partner, connected to the Standard Model predominantly via a U1 vector leptoquark. A TeV scale U1 leptoquark, which couples mostly to third generation fermions, is the only successful single-mediator description of the B-physics anomalies. After calculating the dark matter relic surface, we focus on the most promising experimental avenue: LHC searches for the coloured coannihilation partner. We find that the coloured partner hadronizes and forms meson-like bound states leading to resonant signatures at colliders reminiscent of the quarkonia decay modes in the Standard Model. By recasting existing dilepton and monojet searches we exclude coannihilation partner masses less than 280 GeV and 400 GeV, respectively. Since other existing collider searches do not significantly probe the parameter space, we propose a new dedicated search strategy for pair production of the coloured partner decaying into bbττ final states and dark matter particles. This search is expected to probe the model up to dark matter masses around 600 GeV with current luminosity.

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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