scholarly journals HISTORY OF SUPERSYMMETRIC EXTENSIONS OF THE STANDARD MODEL

2010 ◽  
Vol 25 (06) ◽  
pp. 1091-1121 ◽  
Author(s):  
M. C. RODRIGUEZ
Keyword(s):  
Standard Model ◽  
Fundamental Symmetry ◽  
The Standard Model ◽  
History Of ◽  
The Many

We recall the many obstacles which seemed, long ago, to prevent supersymmetry from possibly being a fundamental symmetry of Nature. We also present their solutions, leading to the construction of the supersymmetric extensions of the Standard Model. Finally we discuss briefly the early experimental searches for supersymmetry.

scholarly journals The history of the muon (g-2) experiments

2019 ◽  
Author(s):  
B. Lee Roberts
Keyword(s):  
Standard Model ◽  
Quantum Electrodynamics ◽  
National Laboratory ◽  
New Physics ◽  
Brookhaven National Laboratory ◽  
Muon Decay ◽  
Higgs Bosons ◽  
The Standard Model ◽  
History Of ◽  
First Time

I discuss the history of the muon (g-2)(g−2) measurements, beginning with the Columbia-Nevis measurement that observed parity violation in muon decay, and also measured the muon gg-factor for the first time, finding g_\mu=2gμ=2. The theoretical (Standard Model) value contains contributions from quantum electrodynamics, the strong interaction through hadronic vacuum polarization and hadronic light-by-light loops, as well as the electroweak contributions from the WW, ZZ and Higgs bosons. The subsequent experiments, first at Nevis and then with increasing precision at CERN, measured the muon anomaly a_\mu = (g_\mu-2)/2aμ=(gμ−2)/2 down to a precision of 7.3 parts per million (ppm). The Brookhaven National Laboratory experiment E821 increased the precision to 0.54 ppm, and observed for the first time the electroweak contributions. Interestingly, the value of a_\muaμ measured at Brookhaven appears to be larger than the Standard Model value by greater than three standard deviations. A new experiment, Fermilab E989, aims to improve on the precision by a factor of four, to clarify whether this result is a harbinger of new physics entering through loops, or from some experimental, statistical or systematic issue.

scholarly journals Determination of the Proton's Weak Charge and Its Constraints on the Standard Model

2019 ◽  
Vol 69 (1) ◽  
pp. 191-217 ◽  
Author(s):  
Roger D. Carlini ◽  
Willem T.H. van Oers ◽  
Mark L. Pitt ◽  
Gregory R. Smith
Keyword(s):  
Standard Model ◽  
Parity Violation ◽  
Valence Quark ◽  
Weak Mixing Angle ◽  
Weak Charge ◽  
Mixing Angle ◽  
The Standard Model ◽  
History Of ◽  
Bsm Physics

This article discusses some of the history of parity-violation experiments that culminated in the Qweak experiment, which provided the first determination of the proton's weak charge [Formula: see text]. The guiding principles necessary to the success of that experiment are outlined, followed by a brief description of the Qweak experiment. Several consistent methods used to determine [Formula: see text] from the asymmetry measured in the Qweak experiment are explained in detail. The weak mixing angle sin2θw determined from [Formula: see text] is compared with results from other experiments. A description of the procedure for using the [Formula: see text] result on the proton to set TeV-scale limits for new parity-violating semileptonic physics beyond the Standard Model (BSM) is presented. By also considering atomic parity-violation results on cesium, the article shows how this result can be generalized to set limits on BSM physics, which couples to any combination of valence quark flavors. Finally, the discovery space available to future weak-charge measurements is explored.

The Standard Model

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Sheldon Lee Glashow
Keyword(s):  
Standard Model ◽  
History Of Physics ◽  
The Third ◽  
The Standard Model ◽  
History Of

The third and final installment in Sheldon Lee Glashow’s history of physics. In this essay Glashow examines a development in which he played a key role, the formulation of the Standard Model.

scholarly journals The many guises of a neutral fermion singlet

2017 ◽  
Vol 32 (08) ◽  
pp. 1730007 ◽  
Author(s):  
Ernest Ma
Keyword(s):  
Standard Model ◽  
Baryon Number ◽  
New Physics ◽  
Spontaneous Breaking ◽  
Particle Interactions ◽  
Neutral Fermion ◽  
The Standard Model ◽  
The Many

The addition of a neutral fermion singlet to the Standard Model (SM) of particle interactions leads to many diverse possibilities. It is not necessarily a right-handed neutrino. I discuss many of the simplest and most interesting scenarios of possible new physics with this approach. In particular, I propose the possible spontaneous breaking of baryon number, resulting in the massless “sakharon”.

scholarly journals CP violating effects in 210Fr and prospects for new physics beyond the Standard Model

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Nanako Shitara ◽  
Nodoka Yamanaka ◽  
Bijaya Kumar Sahoo ◽  
Toshio Watanabe ◽  
Bhanu Pratap Das
Keyword(s):  
Standard Model ◽  
Higgs Sector ◽  
Higgs Doublet ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Internal Electric Field ◽  
Many Body ◽  
The Standard Model ◽  
The Many ◽  
Two Higgs Doublet Model

Abstract We report theoretical results of the electric dipole moment (EDM) of 210Fr which arises from the interaction of the EDM of an electron with the internal electric field in an atom and the scalar-pseudoscalar electron-nucleus interaction; the two dominant sources of CP violation in this atom. Employing the relativistic coupled-cluster theory, we evaluate the enhancement factors for these two CP violating interactions to an accuracy of about 3% and analyze the contributions of the many-body effects. These two quantities in combination with the projected sensitivity of the 210Fr EDM experiment provide constraints on new physics beyond the Standard Model. Particularly, we demonstrate that their precise values are necessary to account for the effect of the bottom quark in models in which the Higgs sector is augmented by nonstandard Yukawa interactions such as the two-Higgs doublet model.

scholarly journals The Discovery of the Higgs Boson at the LHC

2020 ◽  
pp. 263-309
Author(s):  
Peter Jenni ◽  
Tejinder S. Virdee
Keyword(s):  
Higgs Boson ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Hadron Collider ◽  
Higgs Mechanism ◽  
Future Prospects ◽  
The Standard Model ◽  
History Of ◽  
And Performance ◽  
Design And Construction

AbstractIn July 2012 the ATLAS and CMS experiments announced the discovery of a Higgs boson, confirming the conjecture put forward in the 1960’s. This article briefly traces the history of the Brout-Englert-Higgs mechanism, its impact on the elucidation of the standard model, the design and construction of the ATLAS and CMS experiments, and finally the discovery of the Higgs boson. The article outlines some of the challenges faced during the construction of the Large Hadron Collider and its experiments, and their operation and performance. In particular, recent results relating to the properties and couplings of the Higgs boson will be discussed as well future prospects at the LHC.

scholarly journals Physical implications of electroweak monopole

2019 ◽  
Vol 377 (2161) ◽  
pp. 20190038 ◽  
Author(s):  
Y. M. Cho
Keyword(s):  
Standard Model ◽  
Large Scale ◽  
New Physics ◽  
Dirac Monopole ◽  
Magnetic Current ◽  
Practical Applications ◽  
Large Scale Structures ◽  
The Standard Model ◽  
History Of ◽  
Characteristic Features

The electroweak monopole in the standard model, the existence, characteristic features, cosmological production and physical implications are discussed. The discovery of the Higgs particle has been thought to be the ‘final’ test of the standard model. If the standard model is correct, however, it must have the electroweak monopole as the electroweak generalization of the Dirac monopole. This means that the detection of this monopole should become the final and topological test of the standard model. If detected, it becomes the first magnetically charged and stable topological elementary particle in the history of physics. Moreover, it has deep implications in physics. In cosmology, it could generate the primordial magnetic black holes which could explain the dark matter, become the seed of the large-scale structures of the universe, and be the source of the intergalactic magnetic field. Just as importantly, it could generate the hitherto unknown magnetic current which could have huge practical applications. Furthermore, the existence of the monopole requires us to reformulate the perturbative expansion in quantum field theory. This makes the detection of the electroweak monopole a most urgent issue. We discuss useful tips for the MoEDAL detector at LHC and similar experiments on how to detect the monopole successfully. This article is part of a discussion meeting issue ‘Topological avatars of new physics’.

CP ASYMMETRIES IN B0DECAYS BEYOND THE STANDARD MODEL

1991 ◽  
Vol 06 (08) ◽  
pp. 1253-1266 ◽  
Author(s):  
CLAUDIO O. DIB ◽  
DAVID LONDON ◽  
YOSEF NIR
Keyword(s):  
Standard Model ◽  
New Physics ◽  
The Other ◽  
Beyond The Standard Model ◽  
Neutral Currents ◽  
Flavor Changing ◽  
The Standard Model ◽  
Model Predictions ◽  
The Many ◽  
Cp Asymmetries

Of the many ingredients of the Standard Model that are relevant to the analysis of CP asymmetries in B0 decays, some are likely to hold even beyond the Standard Model while others are sensitive to new physics. Consequently, certain predictions are maintained while others may show dramatic deviations from the Standard Model. Many classes of models may show clear signatures when the asymmetries are measured: four quark generations, Z-mediated flavor-changing neutral currents, supersymmetry and “real superweak” models. On the other hand, models of left-right symmetry and multi-Higgs sectors with natural flavor conservation are unlikely to modify the Standard Model predictions.

scholarly journals The gravitino problem in extended gravity cosmologies

2021 ◽  
Vol 136 (2) ◽  
Author(s):  
Salvatore Capozziello ◽  
Gaetano Lambiase
Keyword(s):  
General Relativity ◽  
Standard Model ◽  
Thermal History ◽  
Natural Extension ◽  
Beyond The Standard Model ◽  
Extended Gravity ◽  
The Standard Model ◽  
Unified Theories ◽  
History Of ◽  
The Universe

AbstractThe gravitino problem is investigated in the framework of extended gravity cosmologies. In particular, we consider f(R) gravity, the most natural extension of the Hilbert–Einstein action, and $$f({\mathcal{T}})$$ f ( T ) gravity, the extension of teleparallel equivalent gravity. Since in these theories, the expansion laws of the Universe are modified, as compared to the standard $$\Lambda $$ Λ CDM cosmology, it follows that also the thermal history of particles gets modified. We show that f(R) models allow to avoid the late abundance of gravitinos. In particular, we found that for an appropriate choice of the parameters characterizing the f(R) model, the gravitino abundance turns out to be independent of the reheating temperature. A similar behavior is achieved also in the context of $$f({\mathcal{T}})$$ f ( T ) gravity. In this perspective, we can conclude that geometric corrections to standard General Relativity (and to Teleparallel Equivalent of General Relativity) can improve shortcomings both in cosmology and in unified theories beyond the standard model of particles.

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