scholarly journals Nonperturbative effects in the Standard Model with gauged 1-form symmetry

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Mohamed M. Anber ◽  
Erich Poppitz
Keyword(s):  
Standard Model ◽  
Nonperturbative Effects ◽  
Gauge Group ◽  
Topological Charge ◽  
Lepton Number ◽  
Global Symmetry ◽  
Weak Scale ◽  
Instanton Contribution ◽  
The Standard Model ◽  
Lepton Number Violating

Abstract We study the Standard Model with gauged $$ {\mathrm{\mathbb{Z}}}_{N=2,3,6}^{(1)} $$ ℤ N = 2 , 3 , 6 1 subgroups of its $$ {\mathrm{\mathbb{Z}}}_6^{(1)} $$ ℤ 6 1 1-form global symmetry, making the gauge group $$ \frac{\mathrm{SU}(3)\times \mathrm{SU}(2)\times \mathrm{U}(1)}{{\mathrm{\mathbb{Z}}}_N} $$ SU 3 × SU 2 × U 1 ℤ N . We show that, on a finite $$ {\mathbbm{T}}^3 $$ T 3 , there are self-dual instantons of fractional topological charge. They mediate baryon- and lepton-number violating processes. We compare their amplitudes to the ones due to the usual BPST-instantons. We find that the small hypercharge coupling suppresses the fractional-instanton contribution, unless the torus size is taken sub-Planckian, or extra matter is added above the weak scale. We also discuss these results in light of the cosmological bounds on the torus size.

scholarly journals Gauge Boson Mixing in the 3-3-1 Models with Discrete Symmetries

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
P. V. Dong ◽  
V. T. N. Huyen ◽  
H. N. Long ◽  
H. V. Thuy
Keyword(s):  
Standard Model ◽  
Gauge Boson ◽  
Discrete Symmetries ◽  
Lepton Number ◽  
Neutrino Mixing ◽  
Gauge Bosons ◽  
Neutral Gauge Boson ◽  
Neutral Scalar ◽  
The Standard Model ◽  
Lepton Number Violating

The mixing among gauge bosons in the 3-3-1 models with the discrete symmetries is investigated. To get tribimaximal neutrino mixing, we have to introduce sextets containing neutral scalar components with lepton numberL=1,2. Assignation of VEVs to these fields leads to the mixing of the new gauge bosons and those in the standard model. The mixing in the charged gauge bosons leads to the lepton number violating interactions of theWboson. The same situation happens in the neutral gauge boson sector.

scholarly journals Dark matter and baryogenesis from non-Abelian gauged lepton number

2017 ◽  
Vol 32 (19) ◽  
pp. 1730018 ◽  
Author(s):  
Bartosz Fornal
Keyword(s):  
Dark Matter ◽  
Gauge Symmetry ◽  
Simple Model ◽  
Standard Model ◽  
Gauge Group ◽  
Lepton Number ◽  
Dark Matter Candidate ◽  
The Standard Model ◽  
The Right ◽  
Standard Model Gauge Group

A simple model is constructed based on the gauge symmetry [Formula: see text], with only the leptons transforming nontrivially under [Formula: see text]. The extended symmetry is broken down to the Standard Model gauge group at TeV-scale energies. We show that this model provides a mechanism for baryogenesis via leptogenesis in which the lepton number asymmetry is generated by [Formula: see text] instantons. The theory also contains a dark matter candidate — the [Formula: see text] partner of the right-handed neutrino.

scholarly journals Models of hypercolor based on symplectic gauge group with three heavy vectorlike hyperquarks

2019 ◽  
Vol 28 (13) ◽  
pp. 1941002 ◽  
Author(s):  
Nikolay Volchanskiy ◽  
Vladimir Kuksa ◽  
Vitaly Beylin
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Symmetry Group ◽  
Gauge Group ◽  
Global Symmetry ◽  
Composite Higgs ◽  
Global Symmetry Group ◽  
The Standard Model ◽  
Dynamical Breaking ◽  
Partially Composite

We study possibilities to extend the Standard Model (SM) by three flavors of vectorlike heavy quarks in pseudoreal representation of symplectic hypercolor gauge group. This extension of SM predicts a rich spectra of heavy composite hypermesons and hyperbaryons (all of them carry integer spins) including 14 pseudo-Nambu–Goldstone states emerging in dynamical breaking of the global symmetry group of the H-quarks, [Formula: see text], to its Sp(6) subgroup. The properties of the lightest states depend strongly on the choice of heavy-quark hypercharges. Our focus is placed on the variants of the model with partially composite Higgs boson, i.e. the experimentally observed boson comprised the elementary SM Higgs and a mixture of H-hadrons.

scholarly journals BARYON AND LEPTON NUMBER VIOLATION WITH SCALAR BILINEARS

2002 ◽  
Vol 17 (33) ◽  
pp. 2221-2228 ◽  
Author(s):  
H. V. KLAPDOR-KLEINGROTHAUS ◽  
ERNEST MA ◽  
UTPAL SARKAR
Keyword(s):  
Standard Model ◽  
Beta Decay ◽  
Neutrinoless Double Beta Decay ◽  
Proton Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Lepton Number Violation ◽  
The Standard Model ◽  
Number Violation ◽  
Lepton Number Violating

We consider all possible scalar bilinears, which couple to two fermions of the standard model. The various baryon and lepton number violating couplings allowed by these exotic scalars are studied. We then discuss which are constrained by limits on proton decay (to a lepton and a meson as well as to three leptons), neutron–antineutron oscillations, and neutrinoless double beta decay.

NEUTRINOLESS DOUBLE BETA DECAY EXPERIMENTS

2019 ◽  
pp. 32-39
Author(s):  
N.S. Rumyantseva ◽  
K.N. Gusev
Keyword(s):  
Standard Model ◽  
Beta Decay ◽  
Electroweak Interaction ◽  
Neutrinoless Double Beta Decay ◽  
New Physics ◽  
Lepton Number ◽  
Double Beta Decay ◽  
The Standard Model ◽  
New Generation ◽  
Lepton Number Violating

Neutrinoless double beta decay is a lepton number violating process which is not allowed in the Standard Model (SM) of the electroweak interaction. The discovery of this process will be an unambiguous confirmation of the existence of New Physics outside the SM. At this moment many experiments are being conducted aimed at searching for neutrinoless double beta decay on various isotopes (76Ge, 136Xe, 130Te, 100Mo, etc.). The paper presents a brief overview of the results of some current projects, such as GERDA, MAJORANA, KamLAND-Zen, EXO-200, CUORE and SuperNEMO, and plans for creating a new generation experiments.

scholarly journals Freezing In with lepton flavored fermions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giancarlo D'Ambrosio ◽  
Shiuli Chatterjee ◽  
Ranjan Laha ◽  
Sudhir Kumar Vempati
Keyword(s):  
Standard Model ◽  
Direct Detection ◽  
Lepton Number ◽  
Minimal Flavor Violation ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Lepton Number Violating

Dark, chiral fermions carrying lepton flavor quantum numbers are natural candidates for freeze-in. Small couplings with the Standard Model fermions of the order of lepton Yukawas are `automatic' in the limit of Minimal Flavor Violation. In the absence of total lepton number violating interactions, particles with certain representations under the flavor group remain absolutely stable. For masses in the GeV-TeV range, the simplest model with three flavors, leads to signals at future direct detection experiments like DARWIN. Interestingly, freeze-in with a smaller flavor group such as SU(2) is already being probed by XENON1T.

scholarly journals On the role of leptonic CPV phases in cLFV observables

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
A. Abada ◽  
J. Kriewald ◽  
A. M. Teixeira
Keyword(s):  
Standard Model ◽  
Crucial Role ◽  
Charged Lepton ◽  
Lepton Number ◽  
Majorana Fermions ◽  
Future Observation ◽  
The Standard Model ◽  
Lepton Flavour ◽  
Lepton Number Violating

AbstractIn extensions of the standard model by Majorana fermions, the presence of additional CP violating phases has been shown to play a crucial role in lepton number violating processes. In this work we show that (Dirac and Majorana) CP violating phases can also lead to important effects in charged lepton flavour violating (cLFV) transitions and decays, in some cases with a significant impact for the predicted rates of cLFV observables. We conduct a thorough exploration of these effects in several cLFV observables, and discuss the implications for future observation. We emphasise how the presence of leptonic CP violating phases might lead to modified cLFV rates, and to a possible loss of correlation between cLFV observables.

scholarly journals Pair production of heavy neutrinos in next-to-leading order QCD at the hadron colliders in the inverse seesaw framework

2021 ◽  
Vol 36 (04) ◽  
pp. 2150012
Author(s):  
Arindam Das
Keyword(s):  
Standard Model ◽  
Pair Production ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Lepton Number ◽  
Striking Difference ◽  
Type I ◽  
Leading Order ◽  
The Standard Model ◽  
Lepton Number Violating

The explanation of the small neutrino mass can be depicted using some handsome models like type-I and inverse seesaw where the Standard Model gauge singlet heavy right-handed neutrinos are deployed. The common thing in these two models is a lepton number violating parameter, however, its order of magnitude creates a striking difference between them making the nature of the right-handed heavy neutrinos a major play factor. In the type-I seesaw a large lepton number violating parameter involves the heavy right-handed neutrinos in the form of Majorana fermions while a small lepton number violating parameter being involved in the inverse seesaw demands the pseudo-Dirac nature of the heavy right-handed neutrinos. Such heavy neutrinos are accommodated in these models through the sizable mixings with the Standard Model light neutrinos. In this paper we consider the purely inverse seesaw scenario to study the pair production of the pseudo-Dirac heavy neutrinos followed by their various multilepton decay modes through the leading branching fraction at the leading order and next-to-leading order QCD at the LHC with a center-of-mass energy of 13 TeV and a luminosity of 3000 fb[Formula: see text]. We also consider a prospective 100 TeV hadron collider with luminosities of 3000 fb[Formula: see text] and 30,000 fb[Formula: see text], respectively to study the process. Using anomalous multilepton search performed by the CMS at the 8 TeV with 19.5 fb[Formula: see text] luminosity we show prospective search reaches of the mixing angles for the three lepton and four lepton events at the 13 TeV LHC and 100 TeV hadron collider.

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