Beyond the Standard Model

2021 ◽  
pp. 479-487
Author(s):  
J. Iliopoulos ◽  
T.N. Tomaras
Keyword(s):  
Standard Model ◽  
Simple Group ◽  
Proton Decay ◽  
Grand Unification ◽  
Beyond The Standard Model ◽  
Fundamental Physics ◽  
High Energies ◽  
The Standard Model ◽  
Very High

We review the fundamental physics questions left unanswered by the Standard Model, and we explain why, despite its great successes, the search for physics beyond the Standard Model is a very active field of research. We briefly review the theories of Grand Unification which assume that the SU(3) × SU(2) x U(1) group of the Standard Model is the remnant of a larger, simple or semi-simple group, spontaneously broken at very high energies. These theories predict the phenomenon of proton decay and we discuss possible cosmological consequences of such an instability. We end with the theory of supersymmetry which postulates the existence of an approximate fermion-boson symmetry.

A GLANCE BEYOND THE STANDARD MODEL: LATEST RESULTS FROM THE MEG EXPERIMENT

2014 ◽  
Vol 35 ◽  
pp. 1460390
Author(s):  
SIMEONE DUSSONI
Keyword(s):  
Beyond Standard Model ◽  
Standard Model ◽  
High Intensity ◽  
State Of The Art ◽  
Branching Ratio ◽  
Beyond The Standard Model ◽  
Upper Limit ◽  
The Standard Model ◽  
Key Features ◽  
Very High

The MEG experiment started taking data in 2009 looking for the Standard Model suppressed decay μ → e + γ, which, if observed, can reveal Beyond Standard Model physics. It makes use of state-of-the art detectors optimized for operating in conditions of very high intensity, rejecting as much background as possible. The data taking ended August 2013 and an upgrade R&D is started to push the experimental sensitivity. The present upper limit on the decay Branching Ratio (BR) is presented, obtained with the subset of data from 2009 to 2011 run, together with a description of the key features of the upgraded detector.

scholarly journals Gauge-Higgs EW and grand unification

2016 ◽  
Vol 31 (20n21) ◽  
pp. 1630031 ◽  
Author(s):  
Yutaka Hosotani
Keyword(s):  
Standard Model ◽  
Higgs Field ◽  
Proton Decay ◽  
Grand Unification ◽  
Quantum Level ◽  
Fifth Dimension ◽  
The Standard Model ◽  
Low Energies ◽  
Vector Representations ◽  
Aharonov Bohm

Four-dimensional Higgs field is identified with the extra-dimensional component of gauge potentials in the gauge-Higgs unification scenario. [Formula: see text] gauge-Higgs EW unification in the Randall–Sundrum warped space is successful at low energies. The Higgs field appears as an Aharonov–Bohm phase [Formula: see text] in the fifth dimension. Its mass is generated at the quantum level and is finite. The model yields almost the same phenomenology as the standard model for [Formula: see text], and predicts [Formula: see text] bosons around 6–10 TeV with very broad widths. The scenario is generalized to [Formula: see text] gauge-Higgs grand unification. Fermions are introduced in the spinor and vector representations of [Formula: see text]. Proton decay is naturally forbidden.

Search for dark matter from the centre of the Earth with 8 years of IceCube data

2021 ◽  
Vol 16 (11) ◽  
pp. C11012
Author(s):  
G. Renzi
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Weakly Interacting Massive Particles ◽  
The Body ◽  
Data Sets ◽  
Beyond The Standard Model ◽  
Fundamental Physics ◽  
The Earth ◽  
The Standard Model ◽  
Body Self

Abstract Neutrinos have been proved to be unique messengers in the understanding of fundamental physics processes, and in astrophysical data sets they may provide hints of physics beyond the Standard Model. For example, neutrinos could be the key to discerning between various dark matter models that are based on Weakly Interacting Massive Particles (WIMPs). WIMPs can scatter off standard matter nuclei in the vicinity of massive bodies such as the Sun or the Earth, lose velocity, and be gravitationally trapped in the center of the body. Self-annihilation of dark matter into Standard Model particles may produce an observable flux of neutrinos. For the case of the Earth, an excess of neutrinos coming from the center of the planet could indicate WIMP capture and annihilation at the Earth’s core. The IceCube Neutrino Observatory, located at the geographical South Pole, is sensitive to these excess neutrinos. A search has been conducted on 8 years of IceCube data, probing multiple dark matter channels and masses. With this analysis, we show that IceCube has world-leading sensitivity to the spin-independent dark matter-nucleon scattering cross section above a WIMP mass of 100 GeV.

scholarly journals AMPLITUDES FOR gg→VV′ AND THEIR HIGH ENERGY SUSY CONSTRAINTS

2011 ◽  
Vol 26 (02) ◽  
pp. 209-233 ◽  
Author(s):  
G. J. GOUNARIS ◽  
J. LAYSSAC ◽  
F. M. RENARD
Keyword(s):  
Standard Model ◽  
High Energy ◽  
Supersymmetric Model ◽  
High Energies ◽  
The Standard Model ◽  
Helicity Conservation ◽  
Minimal Supersymmetric Model ◽  
Very High ◽  
Susy Model

We study how the property of asymptotic helicity conservation (HCns), expected for any 2-to-2 process in the minimal supersymmetric model (MSSM), is realized in the processes gg →γγ, γZ, ZZ, W+W-, at one-loop electroweak order and very high energies. The violation of this property for the same process in the standard model (SM) is also shown. This strengthens the claim that HCns is specific to the renormalizable SUSY model, and not generally valid in the SM. HCns strongly reduces the number of nonvanishing 2-to-2 amplitudes at asymptotic energies in the MSSM.

scholarly journals Gravity Induced Anomalies Smearing in Standard Model so that Protons May Never Decay, Except in Black Holes

2020 ◽  
Author(s):  
Stephane Maes
Keyword(s):  
Black Holes ◽  
Standard Model ◽  
New Physics ◽  
Proton Decay ◽  
Lepton Number ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Total Lack

Gravity is not modeled in the Standard Model. The Proton decay, predicted by many GUTs, TOEs, supersymmetry, supergravity theories and superstrings, is forbidden in the Standard Model because the proton is the lightest baryon and the conservation of the lepton and baryon numbers would be violated. In New Physics beyond the Standard Model, such violations could be tolerated because the baryon and lepton number symmetries have chirality anomalies. We discuss that in a multi-fold universe, where gravity emerges from entanglement effects, or in a universe where gravity is strong enough to cause chirality flips of fermions, these anomalies are smeared so that the baryon and lepton symmetries could be no more anomalous, and conservation of the baryon and lepton numbers could be seen as stricter. As a result, proton decay could remain forbidden, except when gravity is extreme. It has significant consequences for theories predicting proton decay but matches the total lack of any proton decay observation so far.

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