scholarly journals A genuine fermionic quintuplet seesaw model: phenomenological introduction

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Saiyad Ashanujjaman ◽  
Kirtiman Ghosh
Keyword(s):  
Center Of Mass ◽  
Majorana Neutrino ◽  
Mass Scale ◽  
Tree Level ◽  
Center Of Mass Energy ◽  
Fermion Masses ◽  
Mass Dimension ◽  
The Masses ◽  
Displaced Vertex ◽  
Lepton Flavour

Abstract We study a model which generates Majorana neutrino masses at tree-level via low-energy effective operator with mass-dimension-9. Introduction of such a higher dimensional operator brings down the lepton number violating mass scale to TeV making such model potentially testable at present or near future colliders. This model possesses several new SU(2)L fermionic multiplets, in particular, three generations of triplets, quadruplets and quintuplets, and thus a rich phenomenology at the LHC. Noting that lepton flavour violation arises very naturally in such setup, we put constraints on the Yukawa couplings and heavy fermion masses using the current experimental bounds on lepton flavour violating processes. We also obtain 95% CL lower bounds on the masses of the triplets, quadruplets and quintuplets using a recent CMS search for multilepton final states with 137 inverse femtobarn integrated luminosity data at 13 TeV center of mass energy. The possibility that the heavy fermions could be long-lived leaving disappearing charge track signatures or displaced vertex at the future colliders like LHeC, FCC-he, MATHUSLA, etc. is also discussed.

Fermion masses and mixings in a 3-3-1 model withQ4symmetry

2019 ◽  
Vol 34 (25) ◽  
pp. 1950198
Author(s):  
V. V. Vien ◽  
D. P. Khoi
Keyword(s):  
Neutrino Mass ◽  
Mass Parameter ◽  
Majorana Neutrino ◽  
Tree Level ◽  
Type I ◽  
Inverted Hierarchy ◽  
Quark Masses ◽  
Fermion Masses ◽  
Majorana Neutrino Mass ◽  
Good Agreement

We construct a renormalizable [Formula: see text] model with [Formula: see text] symmetry accommodating the observed pattern of fermion masses and mixings with Dirac CP violation phase. The smallness of the active neutrino masses arises from a combination of type I and type II seesaw mechanisms. Both normal and inverted neutrino mass ordering are viable in our model in which the obtained physical observables of the lepton sector are well consistent with the global fit of neutrino oscillation data [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)] while the CKM matrix is unity at tree level and the quark masses are in good agreement with the experimental data [Particle Data Group (M. Tanabashi et al.), Phys. Rev. D 98, 030001 (2018)]. Furthermore, the model also predicts an effective Majorana neutrino mass parameter of [Formula: see text] eV for normal hierarchy and [Formula: see text] for inverted hierarchy which are consistent with the constraints given in [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)].

scholarly journals PAIRS-PRODUCTION OF HIGGS IN ASSOCIATION WITH BOTTOM QUARKS PAIRS AT e+e- COLLIDERS

2005 ◽  
Vol 20 (34) ◽  
pp. 2629-2638 ◽  
Author(s):  
A. GUTIÉRREZ-RODRÍGUEZ ◽  
M. A. HERNÁNDEZ-RUÍZ ◽  
O. A. SAMPAYO
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
Center Of Mass ◽  
Feynman Diagrams ◽  
Tree Level ◽  
Bottom Quarks ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
The Standard Model ◽  
Complete Set

In a previous paper, we studied the Higgs pair production in the standard model with the reaction [Formula: see text]. Based on this, we study the Higgs pair production via [Formula: see text]. We evaluate the total cross-section of [Formula: see text] and calculate the total number of events considering the complete set of Feynman diagrams at tree-level, and compare this process with the process [Formula: see text]. The numerical computation is done for the energy which is expected to be available at a possible Next Linear e+e- Collider with a center-of-mass energy 800, 1000, 1600 GeV and luminosity 1000 fb-1.

NEUTRAL HIGGS BOSON PAIR-PRODUCTION AND TRILINEAR SELF-COUPLINGS IN THE MSSM AT ILC AND CLIC ENERGIES

2009 ◽  
Vol 24 (28n29) ◽  
pp. 5299-5318 ◽  
Author(s):  
A. GUTIÉRREZ-RODRÍGUEZ ◽  
M. A. HERNÁNDEZ-RUÍZ ◽  
O. A. SAMPAYO
Keyword(s):  
Pair Production ◽  
Linear Collider ◽  
Center Of Mass ◽  
Higgs Bosons ◽  
Tree Level ◽  
Mass Energy ◽  
Boson Pair ◽  
Boson Pair Production ◽  
Center Of Mass Energy ◽  
Complete Set

We study pair-production as well as the triple self-couplings of the neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) at the future International Linear e+e-Collider (ILC) and Compact Linear Collider (CLIC). The analysis is based on the reactions [Formula: see text] with hi= h, H, A. We evaluate the total cross-section for both [Formula: see text] and calculate the total number of events considering the complete set of Feynman diagrams at tree-level. We vary the triple couplings κλhhh, κλHhh, κλhAA, κλHAA, κλhHHand κλHHHwithin the range κ = -1 and +2. The numerical computation is done for the energies expected at the ILC with a center-of-mass energy 500, 1000, 1600 GeV and a luminosity 1000 fb-1. The channels [Formula: see text] and [Formula: see text] are also discussed to a center-of-mass energy of 3 TeV and luminosities of 1000 fb-1and 5000 fb-1.

scholarly journals Production and Decay of Up-Type and Down-Type New Heavy Quarks through Anomalous Interactions at the LHC

2015 ◽  
Vol 2015 ◽  
pp. 1-14
Author(s):  
İ. T. Çakır ◽  
S. Kuday ◽  
O. Çakır
Keyword(s):  
Heavy Quark ◽  
Center Of Mass ◽  
Heavy Quarks ◽  
Mass Energy ◽  
Anomalous Couplings ◽  
Center Of Mass Energy ◽  
The Masses ◽  
Integrated Luminosity

We study the processpp→QV+X(whereQ=t,bandV=g,γ,andZ) through the anomalous interactions of the new heavy quarks at the LHC. Considering the present limits on the masses and mixings, the signatures of the heavy quark anomalous interactions are discussed and analysed at the LHC for the center of mass energy of 13 TeV. An important sensitivity to anomalous couplingsκgt′/Λ=0.10 TeV−1,κγt′/Λ=0.14 TeV−1,κZt′/Λ=0.19 TeV−1andκgb′/Λ=0.15 TeV−1,κZb′/Λ=0.19 TeV−1,κγb′/Λ=0.30 TeV−1for the mass of 750 GeV of the new heavy quarkst′andb′can be reached for an integrated luminosity ofLint=100 fb−1.

scholarly journals Search for lepton flavour violation with the ATLAS experiment

2019 ◽  
Author(s):  
Brian Le
Keyword(s):  
Z Boson ◽  
Center Of Mass ◽  
Beyond The Standard Model ◽  
Atlas Experiment ◽  
Lepton Flavour Violation ◽  
Center Of Mass Energy ◽  
The Standard Model ◽  
Flavour Violation ◽  
8 Tev ◽  
Lepton Flavour

Lepton flavour violation (LFV) is a striking signature of potential beyond the Standard Model physics. The search for LFV with the ATLAS detector is reported in searches focusing on the decay of the Higgs boson, the Z boson and of a heavy neutral gauge boson, Z’, using pp collisions data with a center of mass energy of 8 TeV and 13 TeV.

scholarly journals ANSATZ FOR QUARK, CHARGED LEPTON, AND NEUTRINO MASSES IN SUSY GUTs

1993 ◽  
Vol 08 (22) ◽  
pp. 2099-2109 ◽  
Author(s):  
H. DREINER ◽  
G.K. LEONTARIS ◽  
N.D. TRACAS
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Mass Scale ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
Tau Neutrino ◽  
The Masses ◽  
Majorana Neutrino Mass

We extend a fermion mass matrix ansatz by Giudice to include neutrino masses. The previous predictions are maintained. With two additional parameters, a large Majorana neutrino mass and a hierarchy factor, we have seven further low energy predictions: the masses of the neutrinos, the mixing angles and the phase in the leptonic sector. We choose a reasonable hierarchy of Majorana masses and fit the overall mass scale according to a solution of the solar neutrino problem via the MSW mechanism, which is in agreement with the 37 Cl , Kamiokande, SAGE and GALLEX data. We then also obtain a cosmologically interesting tau-neutrino mass.

scholarly journals Search for chargino-neutralino production in events with Higgs and W bosons using 137 fb−1 of proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Higgs Boson ◽  
W Boson ◽  
Center Of Mass ◽  
W Bosons ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Missing Transverse Momentum ◽  
The Masses ◽  
Proton Proton Collisions

Abstract A search for electroweak production of supersymmetric (SUSY) particles in final states with one lepton, a Higgs boson decaying to a pair of bottom quarks, and large missing transverse momentum is presented. The search uses data from proton-proton collisions at a center-of-mass energy of 13 TeV collected using the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb−1. The observed yields are consistent with backgrounds expected from the standard model. The results are interpreted in the context of a simplified SUSY model of chargino-neutralino production, with the chargino decaying to a W boson and the lightest SUSY particle (LSP) and the neutralino decaying to a Higgs boson and the LSP. Charginos and neutralinos with masses up to 820 GeV are excluded at 95% confidence level when the LSP mass is small, and LSPs with mass up to 350 GeV are excluded when the masses of the chargino and neutralino are approximately 700 GeV.

scholarly journals Time-delayed electrons from neutral currents at the LHC

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Kingman Cheung ◽  
Kechen Wang ◽  
Zeren Simon Wang
Keyword(s):  
Standard Model ◽  
Center Of Mass ◽  
Supersymmetric Particle ◽  
Neutral Currents ◽  
Final State ◽  
Center Of Mass Energy ◽  
Heavy Gauge Boson ◽  
The Standard Model ◽  
Displaced Vertex ◽  
Two Jets

Abstract We investigate long-lived particles (LLPs) produced in pair from neutral currents and decaying into a displaced electron plus two jets at the LHC, utilizing the proposed minimum ionizing particle timing detector at CMS. We study two benchmark models: the R-parity-violating supersymmetry with the lightest neutralinos being the lightest supersymmetric particle and two different U(1) extensions of the standard model with heavy neutral leptons (HNLs). The light neutralinos are produced from the standard model Z-boson decays via small Higgsino components, and the HNLs arise from decays of a heavy gauge boson, Z′. By simulating the signal processes at the HL-LHC with the center-of-mass energy $$ \sqrt{s} $$ s = 14 TeV and integrated luminosity of 3 ab−1, our analyses indicate that the search strategy based on a timing trigger and the final state kinematics has the potential to probe the parameter space that is complementary to other traditional LLP search strategies such as those based on the displaced vertex.

scholarly journals Lepto-axiogenesis

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Raymond T. Co ◽  
Nicolas Fernandez ◽  
Akshay Ghalsasi ◽  
Lawrence J. Hall ◽  
Keisuke Harigaya
Keyword(s):  
Parametric Resonance ◽  
Domain Walls ◽  
Radial Component ◽  
Majorana Neutrino ◽  
Mass Scale ◽  
Baryon Asymmetry ◽  
Kaon Decays ◽  
Lepton Asymmetry ◽  
The Masses ◽  
Supersymmetric Theories

Abstract We propose a baryogenenesis mechanism that uses a rotating condensate of a Peccei-Quinn (PQ) symmetry breaking field and the dimension-five operator that gives Majorana neutrino masses. The rotation induces charge asymmetries for the Higgs boson and for lepton chirality through sphaleron processes and Yukawa interactions. The dimension-five interaction transfers these asymmetries to the lepton asymmetry, which in turn is transferred into the baryon asymmetry through the electroweak sphaleron process. QCD axion dark matter can be simultaneously produced by dynamics of the same PQ field via kinetic misalignment or parametric resonance, favoring an axion decay constant fa ≲ 1010 GeV, or by conventional misalignment and contributions from strings and domain walls with fa ∼ 1011 GeV. The size of the baryon asymmetry is tied to the mass of the PQ field. In simple supersymmetric theories, it is independent of UV parameters and predicts the supersymmtry breaking mass scale to be $$ \mathcal{O} $$ O (10 − 104) TeV, depending on the masses of the neutrinos and whether the condensate is thermalized during a radiation or matter dominated era. The high supersymmetry breaking mass scale may be free from cosmological and flavor/CP problems. We also construct a theory where TeV scale supersymmetry is possible. Parametric resonance may give warm axions, and the radial component of the PQ field may give signals in rare kaon decays from mixing with the Higgs and in dark radiation.

scholarly journals Fermion mass hierarchy and g − 2 anomalies in an extended 3HDM Model

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
A. E. Cárcamo Hernández ◽  
Sergey Kovalenko ◽  
M. Maniatis ◽  
Ivan Schmidt
Keyword(s):  
Magnetic Moments ◽  
Higgs Doublet ◽  
Tree Level ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Strange Quarks ◽  
Lepton Flavor ◽  
Fermion Masses ◽  
Dark Matter Relic Density ◽  
The Masses

Abstract We propose an extension of the three-Higgs-doublet model (3HDM), where the Standard Model (SM) particle content is enlarged by the inclusion of two inert SU2L scalar doublets, three inert and two active electrically neutral gauge singlet scalars, charged vector like fermions and Majorana neutrinos. These additional particles are introduced to generate the SM fermion mass hierarchy from a sequential loop suppression mechanism. In our model the top and exotic fermion masses appear at tree level, whereas the remaining fermions get their masses radiatively. Specifically, bottom, charm, tau and muon masses appear at 1-loop; the masses for the light up, down and strange quarks as well as for the electron at 2-loop and masses for the light active neutrinos at 3-loop. Our model successfully accounts for SM fermion masses and mixings and accommodates the observed Dark Matter relic density, the electron and muon anomalous magnetic moments, as well the constraints arising from charged Lepton Flavor Violating (LFV) processes. The proposed model predicts charged LFV decays within the reach of forthcoming experiments.

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