scholarly journals Leptoquarks in oblique corrections and Higgs signal strength: status and prospects

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Andreas Crivellin ◽  
Dario Müller ◽  
Francesco Saturnino
Keyword(s):  
Standard Model ◽  
Signal Strength ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Discovery Potential ◽  
Weak Constraints ◽  
The Impact ◽  
Standard Model Gauge Group ◽  
Higgs Signal

Abstract Leptoquarks (LQs) are predicted within Grand Unified Theories and are well motivated by the current flavor anomalies. In this article we investigate the impact of scalar LQs on Higgs decays and oblique corrections as complementary observables in the search for them. Taking into account all five LQ representations under the Standard Model gauge group and including the most general mixing among them, we calculate the effects in h → γγ, h → gg, h → Zγ and the Peskin-Takeuchi parameters S, T and U. We find that these observables depend on the same Lagrangian parameters, leading to interesting correlations among them. While the current experimental bounds only yield weak constraints on the model, these correlations can be used to distinguish different LQ representations at future colliders (ILC, CLIC, FCC-ee and FCC-hh), whose discovery potential we are going to discuss.

Complexification of the Exceptional Jordan Algebra and Its Application to Particle Physics

2021 ◽  
Vol 61 ◽  
pp. 1-16
Author(s):  
Daniele Corradetti ◽  
Keyword(s):  
Standard Model ◽  
Gauge Group ◽  
Jordan Algebra ◽  
Particle Physics ◽  
Compact Form ◽  
Symmetric Extension ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Standard Model Gauge Group

Recent papers contributed revitalizing the study of the exceptional Jordan algebra $\mathfrak{h}_{3}(\mathbb{O})$ in its relations with the true Standard Model gauge group $\mathrm{G}_{SM}$. The absence of complex representations of $\mathrm{F}_{4}$ does not allow $\Aut\left(\mathfrak{h}_{3}(\mathbb{O})\right)$ to be a candidate for any Grand Unified Theories, but the automorphisms of the complexification of this algebra, i.e., $\mathfrak{h}_{3}^{\mathbb{C}}(\mathbb{O})$, are isomorphic to the compact form of $\mathrm{E}_{6}$ and similar constructions lead to the gauge group of the minimal left-right symmetric extension of the Standard Model.

scholarly journals SPARTICLE MASS SPECTRUM IN GRAND UNIFIED THEORIES

2007 ◽  
Vol 22 (19) ◽  
pp. 3229-3259 ◽  
Author(s):  
B. ANANTHANARAYAN ◽  
P. N. PANDITA
Keyword(s):  
Mass Spectrum ◽  
Gauge Group ◽  
Gauge Groups ◽  
Grand Unified Theories ◽  
Renormalization Group Equations ◽  
The Standard Model ◽  
Unified Theories ◽  
The One ◽  
The Impact ◽  
Standard Model Gauge Group

We carry out a detailed analysis of sparticle mass spectrum in supersymmetric grand unified theories. We consider the spectroscopy of the squarks and sleptons in SU (5) and SO (10) grand unified theories, and show how the underlying supersymmetry breaking parameters of these theories can be determined from a measurement of different sparticle masses. This analysis is done analytically by integrating the one-loop renormalization group equations with appropriate boundary conditions implied by the underlying grand unified gauge group. We also consider the impact of nonuniversal gaugino masses on the sparticle spectrum, especially the neutralino and chargino masses which arise in supersymmetric grand unified theories with nonminimal gauge kinetic function. In particular, we study the interrelationships between the squark and slepton masses which arise in grand unified theories at the one-loop level, which can be used to distinguish between the different underlying gauge groups and their breaking pattern to the Standard Model gauge group. We also comment on the corrections that can affect these one-loop results.

scholarly journals the complexification of the exceptional Jordan algebra and applications to particle physics

2021 ◽  
Author(s):  
Daniele Corradetti
Keyword(s):  
Standard Model ◽  
Gauge Group ◽  
Jordan Algebra ◽  
Particle Physics ◽  
Proper Subgroup ◽  
Group Of Automorphisms ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Standard Model Gauge Group

Abstract Recent papers of Todorov and Dubois-Violette[4] and Krasnov[7] contributed revitalizing the study of the exceptional Jordan algebra h3(O) in its relations with the true Standard Model gauge group GSM. The absence of complex representations of F4 does not allow Aut (h3 (O)) to be a candidate for any Grand Unified Theories, but the group of automorphisms of the complexification of this algebra isisomorphic to the compact form of E6. Following Boyle in [12], it is then easy to show that the gauge group of the minimal left-right symmetric extension of the Standard Model is isomorphic to a proper subgroup of Aut(C⊗h3(O))

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.

scholarly journals E6 inspired SUSY models with custodial symmetry

2018 ◽  
Vol 33 (31) ◽  
pp. 1844007 ◽  
Author(s):  
R. Nevzorov
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Exotic States ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Low Energies ◽  
Custodial Symmetry ◽  
Susy Models

The breakdown of [Formula: see text] within the supersymmetric (SUSY) Grand Unified Theories (GUTs) can result in SUSY extensions of the standard model (SM) based on the SM gauge group together with extra [Formula: see text] gauge symmetry under which right-handed neutrinos have zero charge. In these [Formula: see text] extensions of the minimal supersymmetric standard model (MSSM) a single discrete [Formula: see text] symmetry may be used to suppress the most dangerous operators, that give rise to proton decay as well as nondiagonal flavour transitions at low energies. The SUSY models under consideration involves [Formula: see text] and extra exotic matter beyond the MSSM. We discuss leptogenesis within this SUSY model and argue that the extra exotic states may lead to the nonstandard Higgs decays.

scholarly journals HEAVY-NEUTRINO EFFECTS ON τ-LEPTON DECAYS

1994 ◽  
Vol 09 (38) ◽  
pp. 3595-3604 ◽  
Author(s):  
A. PILAFTSIS
Keyword(s):  
Standard Model ◽  
Heavy Neutrino ◽  
Lepton Flavor ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Lepton Decays ◽  
The One

Minimal extensions of the standard model that are motivated by grand unified theories or superstring models with an E6 symmetry can naturally predict heavy neutrinos of Dirac or Majorana nature. Such heavy neutral leptons violate the decoupling theorem at the one-loop electroweak order and hence offer a unique chance for possible lepton-flavor decays of the τ-lepton, e.g. τ→eee or τ→μμμ, to be seen in LEP experiments. We analyze such decays in models with three and four generations.

Fundamental Interactions

2017 ◽  
Author(s):  
Laurent Baulieu ◽  
John Iliopoulos ◽  
Roland Sénéor
Keyword(s):  
Standard Model ◽  
Magnetic Monopoles ◽  
Fundamental Interactions ◽  
Exceptional Groups ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories

The experimental successes of the standard model. The motivation for going beyond. General discussion of grand unified theories, The models based on SU(5), O(10), and exceptional groups. Electric–magnetic duality and magnetic monopoles in grand unified theories.

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.

scholarly journals Probing unified theories with reduced couplings at future hadron colliders

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
S. Heinemeyer ◽  
J. Kalinowski ◽  
W. Kotlarski ◽  
M. Mondragón ◽  
G. Patellis ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Renormalization Group ◽  
Standard Model ◽  
Higgs Bosons ◽  
Hadron Colliders ◽  
Group Invariant ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Discovery Potential ◽  
Successful Reduction

AbstractThe search for renormalization group invariant relations among parameters to all orders in perturbation theory constitutes the basis of the reduction of couplings concept. Reduction of couplings can be achieved in certain $$N=1$$ N = 1 supersymmetric grand unified theories and few of them can become even finite at all loops. We review the basic idea, the tools that have been developed as well as the resulting theories in which successful reduction of couplings has been achieved so far. These include: (i) a reduced version of the minimal $$N = 1\ SU(5)$$ N = 1 S U ( 5 ) model, (ii) an all-loop finite $$N = 1\ SU(5)$$ N = 1 S U ( 5 ) model, (iii) a two-loop finite $$N = 1\ SU(3)^3$$ N = 1 S U ( 3 ) 3 model and finally (vi) a reduced version of the Minimal Supersymmetric Standard Model. In this paper we present a number of benchmark scenarios for each model and investigate their observability at existing and future hadron colliders. The heavy supersymmetric spectra featured by each of the above models are found to be beyond the reach of the 14 TeV HL-LHC. It is also found that the reduced version of the MSSM is already ruled out by the LHC searches for heavy neutral MSSM Higgs bosons. In turn the discovery potential of the 100 TeV FCC-hh is investigated and found that large parts of the predicted spectrum of these models can be tested, but the higher mass regions are beyond the reach even of the FCC-hh.

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.

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