scholarly journals Beyond the Standard Model at LEP

1991 ◽  
Vol 336 (1642) ◽  
pp. 247-259 ◽  
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Beyond The Standard Model ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Massive Neutrinos ◽  
Supersymmetric Particles ◽  
The Universe

LEP data constrain severely many proposed extensions of the Standard Model. These include: massive neutrinos, which are now largely excluded as candidates for the dark matter of the Universe; supersymmetric particles, the lightest of which would still constitute detectable dark matter; technicolour, of which many favoured versions are now excluded by precision electroweak measurements; and grand unified theories, of which LEP data favour supersymmetric versions.

Frontiers of Physics

2017 ◽  
Author(s):  
Nicholas Manton ◽  
Nicholas Mee
Keyword(s):  
Standard Model ◽  
Beyond The Standard Model ◽  
Epr Paradox ◽  
Grand Unified Theories ◽  
Alternative Description ◽  
The Standard Model ◽  
Unified Theories ◽  
Modern Physics ◽  
The Universe

Despite the overwhelming successes of modern physics, there are questions that remain to be answered and these are considered in the final chapter. The interpretation of quantum mechanics is discussed, including the EPR paradox, the Aspect experiments and quantum entanglement. Next, the question of whether particles are really point-like and the possibility of an alternative description in terms of solitons is considered. The Skyrmion and the Standard Model sphaleron are described. Unexplained features of the universe, such as the matter–antimatter asymmetry, the existence of dark matter and the even more mysterious dark energy, are discussed. There is also a critique of the loose ends of the Standard Model and the need for a quantum theory of gravity. The chapter concludes with a look beyond the Standard Model at the arguments and evidence in favour of Grand Unified Theories and ultimately string theory.

Particle physics today, tomorrow and beyond

2018 ◽  
Vol 33 (02) ◽  
pp. 1830003 ◽  
Author(s):  
John Ellis
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Particle Physics ◽  
Beyond The Standard Model ◽  
Visible Matter ◽  
The Standard Model ◽  
Cosmological Inflation ◽  
The Stability ◽  
The Universe ◽  
Lhc I

The most important discovery in particle physics in recent years was that of the Higgs boson, and much effort is continuing to measure its properties, which agree obstinately with the Standard Model, so far. However, there are many reasons to expect physics beyond the Standard Model, motivated by the stability of the electroweak vacuum, the existence of dark matter and the origin of the visible matter in the Universe, neutrino physics, the hierarchy of mass scales in physics, cosmological inflation and the need for a quantum theory for gravity. Most of these issues are being addressed by the experiments during Run 2 of the LHC, and supersymmetry could help resolve many of them. In addition to the prospects for the LHC, I also review briefly those for direct searches for dark matter and possible future colliders.

Particle physicists’ candidates for dark matter

1986 ◽  
Vol 320 (1556) ◽  
pp. 475-485 ◽  
Keyword(s):  
Dark Matter ◽  
Big Bang ◽  
Strong Interactions ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Massive Neutrinos ◽  
Supersymmetric Particles ◽  
The Big Bang

A review is presented of the candidates for dark matter that arise in different particle theories. These include massive neutrinos and monopoles in grand unified theories, axions arising from attempts to explain cp conservation in the strong interactions, stable supersymmetric particles such as photinos, gravitinos or sneutrinos, and other possible stable relics from the Big Bang. Wherever possible, relations to laboratory information and possible experiments directly sensitive to the different dark-matter candidates are discussed.

scholarly journals Outstanding questions: physics beyond the Standard Model

2012 ◽  
Vol 370 (1961) ◽  
pp. 818-830 ◽  
Author(s):  
John Ellis
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Particle Physics ◽  
Hadron Collider ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
The Difference ◽  
The Universe

The Standard Model of particle physics agrees very well with experiment, but many important questions remain unanswered, among them are the following. What is the origin of particle masses and are they due to a Higgs boson? How does one understand the number of species of matter particles and how do they mix? What is the origin of the difference between matter and antimatter, and is it related to the origin of the matter in the Universe? What is the nature of the astrophysical dark matter? How does one unify the fundamental interactions? How does one quantize gravity? In this article, I introduce these questions and discuss how they may be addressed by experiments at the Large Hadron Collider, with particular attention to the search for the Higgs boson and supersymmetry.

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.

Physics beyond quarks and leptons

1986 ◽  
Vol 404 (1827) ◽  
pp. 273-284
Keyword(s):  
Standard Model ◽  
Experimental Tests ◽  
Building Blocks ◽  
Beyond The Standard Model ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Complete Theories ◽  
Near Future

Quarks and leptons are used as basic building blocks in the construction of more complete theories beyond the standard model. Some of these are discussed, including grand unified theories and supersymmetry. The prospects for experimental tests of these ideas both now and in the near future are reviewed.

Cosmological implications of lepton number violation

2018 ◽  
Vol 33 (31) ◽  
pp. 1844017
Author(s):  
Heinrich Päs
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Lepton Number ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
Model Framework ◽  
Lepton Number Violation ◽  
The Standard Model ◽  
Number Violation ◽  
The Universe

The abundances of baryons and leptons are not only closely related to each other and to the generation of neutrino masses but may also be linked to the dark matter in the Universe. In this paper we review how a consistent physics beyond the Standard Model framework for cosmology and neutrino masses could arise by studying these interrelations.

scholarly journals Search for dark matter in association with an energetic photon in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Dark Matter ◽  
Transverse Momentum ◽  
Standard Model ◽  
Confidence Level ◽  
Axial Vector ◽  
Beyond The Standard Model ◽  
Proton Proton ◽  
Missing Transverse Momentum ◽  
Upper Limits ◽  
The Standard Model

Abstract A search for dark matter is conducted in final states containing a photon and missing transverse momentum in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV. The data, collected during 2015–2018 by the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139 fb−1. No deviations from the predictions of the Standard Model are observed and 95% confidence-level upper limits between 2.45 fb and 0.5 fb are set on the visible cross section for contributions from physics beyond the Standard Model, in different ranges of the missing transverse momentum. The results are interpreted as 95% confidence-level limits in models where weakly interacting dark-matter candidates are pair-produced via an s-channel axial-vector or vector mediator. Dark-matter candidates with masses up to 415 (580) GeV are excluded for axial-vector (vector) mediators, while the maximum excluded mass of the mediator is 1460 (1470) GeV. In addition, the results are expressed in terms of 95% confidence-level limits on the parameters of a model with an axion-like particle produced in association with a photon, and are used to constrain the coupling gaZγ of an axion-like particle to the electroweak gauge bosons.

scholarly journals A global view of the off-shell Higgs portal

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Maximilian Ruhdorfer ◽  
Ennio Salvioni ◽  
Andreas Weiler
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Vector Boson ◽  
Effective Interaction ◽  
Goldstone Boson ◽  
High Energy ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Higgs Portal ◽  
First Time

We study for the first time the collider reach on the derivative Higgs portal, the leading effective interaction that couples a pseudo Nambu-Goldstone boson (pNGB) scalar Dark Matter to the Standard Model. We focus on Dark Matter pair production through an off-shell Higgs boson, which is analyzed in the vector boson fusion channel. A variety of future high-energy lepton colliders as well as hadron colliders are considered, including CLIC, a muon collider, the High-Luminosity and High-Energy versions of the LHC, and FCC-hh. Implications on the parameter space of pNGB Dark Matter are discussed. In addition, we give improved and extended results for the collider reach on the marginal Higgs portal, under the assumption that the new scalars escape the detector, as motivated by a variety of beyond the Standard Model scenarios.

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