scholarly journals Lepton number violation in a unified framework

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Yuta Kawamura ◽  
Yamato Matsuo ◽  
Takuya Morozumi ◽  
Apriadi Salim Adam ◽  
Yusuke Shimizu ◽  
...  
Keyword(s):  
Time Evolution ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Mass Term ◽  
Majorana Neutrino ◽  
Lepton Number ◽  
Mass Hierarchy ◽  
Unified Framework ◽  
Initial State ◽  
Lepton Family

Abstract We study the time evolution of lepton family number for a neutrino that forms an SU(2) doublet with a charged lepton. The lepton family number is defined through a weak basis of the SU(2) doublet in which the charged lepton mass matrix is a real and diagonal one. The lepton family number carried by the neutrino is defined with a left-handed current of the neutrino family. We study the time evolution of the lepton family number operator for the Majorana neutrino. To be definite, we introduce the mass term at $t=0$ and study the time evolution of the lepton family number for the later time. Since the operator in the flavor eigenstate is continuously connected to that of the mass eigenstate, the creation and annihilation operators for the flavor eigenstates are related to those of the mass eigenstates. The total lepton number of the Majorana neutrino is conserved. By choosing a specific flavor eigenstate of the neutrino as an initial state, we compute the time evolution of all lepton family numbers. They are sensitive to Majorana and Dirac phases and are also sensitive to the absolute mass and mass hierarchy of neutrinos.

scholarly journals Time Evolution of Lepton Number Carried by Majorana Neutrinos

2021 ◽  
Author(s):  
Apriadi Salim Adam ◽  
Nicholas J Benoit ◽  
Yuta Kawamura ◽  
Yamato Matsuo ◽  
Takuya Morozumi ◽  
...  
Keyword(s):  
Time Evolution ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Mass Term ◽  
Big Bang ◽  
Mass Hierarchy ◽  
Majorana Mass ◽  
Cosmic Neutrino Background ◽  
Cosmic Neutrino ◽  
Lepton Family

Abstract We revisit the time evolution of the lepton family number for a SU(2) doublet consisting of a neutrino and a charged lepton. The lepton family number is defined through the weak basis of the SU(2) doublet, where the charged lepton mass matrix is real and diagonal. The lepton family number carried by the neutrino is defined by the left-handed current of the neutrino family. For this work we assume the neutrinos have Majorana mass. This Majorana mass term is switched on at time t = 0 and the lepton family number is evolved. Since the operator in the avor eigenstate is continuously connected to that of the mass eigenstate, the creation and annihilation operators for the two eigenstates are related to each other. We compute the time evolution of all lepton family numbers by choosing a specific initial avor eigenstate for a neutrino. The evolution is studied for relativistic and nonrelativistic neutrinos. The nonrelativistic region is of particular interest for the Cosmic Neutrino Background predicted from big bang models. In that region we find the lepton family numbers are sensitive to Majorana and Dirac phases, the absolute mass, and mass hierarchy of neutrinos.

scholarly journals NEUTRINO MASS MATRIX FROM Δ(27) SYMMETRY

2006 ◽  
Vol 21 (25) ◽  
pp. 1917-1921 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Neutrino Mass ◽  
Simple Form ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Discrete Subgroup ◽  
Majorana Neutrino ◽  
Neutrino Mass Matrix ◽  
Mass Matrices ◽  
Majorana Neutrino Mass

The discrete subgroup Δ(27) of SU(3) has some interesting properties which may be useful for understanding charged-lepton and neutrino mass matrices. Assigning leptons to the 3 and [Formula: see text] representations of Δ(27), a simple form of the Majorana neutrino mass matrix is obtained and compared to present data.

scholarly journals Relating lepton mixing angles with lepton mass hierarchy

2016 ◽  
Vol 31 (04n05) ◽  
pp. 1650002
Author(s):  
Debasish Borah
Keyword(s):  
Neutrino Mass ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Mass Matrices ◽  
Model Independent ◽  
The Difference

We revisit the possibility of relating lepton mixing angles with lepton mass hierarchies in a model-independent way. Guided by the existence of such relations in the quark sector, we first consider all the mixing angles, both in charged lepton and neutrino sectors to be related to the respective mass ratios. This allows us to calculate the leptonic mixing angles observed in neutrino oscillations as functions of the lightest neutrino mass. We show that for both normal and inverted hierarchical neutrino masses, this scenario does not give rise to correct leptonic mixing angles. We then show that correct leptonic mixing angles can be generated with normal hierarchical neutrino masses if the relation between mixing angle and mass ratio is restricted to 1–2 and 1–3 mixing in both charged lepton and neutrino sectors leaving the 2–3 mixing angles as free parameters. We then restrict the lightest neutrino mass as well as the difference between 2–3 mixing angles in charged lepton and neutrino sectors from the requirement of producing correct leptonic mixing angles. We constrain the lightest neutrino mass to be around 0.002 eV and leptonic Dirac CP phase [Formula: see text] such that [Formula: see text]. We also construct the leptonic mass matrices in terms of 2–3 mixing angles and lightest neutrino mass and briefly comment on the possibility of realizing texture zeros in the neutrino mass matrix.

scholarly journals CONSERVING THE LEPTON NUMBER Le-Lμ-LτIN THE EXACT SOLUTION OF A 3-3-1 GAUGE MODEL WITH RIGHT-HANDED NEUTRINOS

2007 ◽  
Vol 22 (13) ◽  
pp. 939-948 ◽  
Author(s):  
ADRIAN PALCU
Keyword(s):  
Exact Solution ◽  
Mass Matrix ◽  
Mass Splitting ◽  
Lepton Number ◽  
Mass Hierarchy ◽  
Gauge Model ◽  
Mixing Angles ◽  
Neutrino Sector ◽  
Absolute Mass ◽  
Breaking Scale

In this paper we consider a plausible scenario with conserved lepton number L = Le-Lμ-Lτwithin the framework of the exact solution of a particular 3-3-1 gauge model. We discuss the consequences of conserving this global leptonic symmetry from the viewpoint of the neutrino mass matrix constructed via special Yukawa terms (involving tensor products among Higgs triplets). We prove that the actual experimental data can naturally be reproduced by our scenario since soft breaking terms with respect to this lepton symmetry are properly introduced. As a consequence, our solution predicts for the neutrino sector the correct mass splitting ratio [Formula: see text], the inverted mass hierarchy, the correct values for the observed mixing angles ( sin2θ23≃0.5 and sin2θ12= 0.31) and the absolute mass of the lightest neutrino (m0~ 0.001 eV) independent of the breaking scale of the model.

scholarly journals LEPTON FAMILY SYMMETRY AND NEUTRINO MASS MATRIX

2004 ◽  
Vol 19 (08) ◽  
pp. 577-582 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Solar Neutrino ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Diagonal Form ◽  
Family Symmetry ◽  
The Standard Model ◽  
Lepton Family

The standard model of leptons is extended to accommodate a discrete Z3×Z2 family symmetry. After rotating the charged-lepton mass matrix to its diagonal form, the neutrino mass matrix reveals itself as very suitable for explaining atmospheric and solar neutrino oscillation data. A generic requirement of this approach is the appearance of three Higgs doublets at the electroweak scale, with observable flavor violating decays.

scholarly journals Minimal 3-loop neutrino mass models and charged lepton flavor violation

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Ricardo Cepedello ◽  
Martin Hirsch ◽  
Paulina Rocha-Morán ◽  
Avelino Vicente
Keyword(s):  
Neutrino Mass ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Lepton Flavor Violation ◽  
Minimal Models ◽  
Yukawa Couplings ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Neutrino Mass Models

Abstract We study charged lepton flavor violation for the three most popular 3-loop Majorana neutrino mass models. We call these models “minimal” since their particle content correspond to the minimal sets for which genuine 3-loop models can be constructed. In all the three minimal models the neutrino mass matrix is proportional to some powers of Standard Model lepton masses, providing additional suppression factors on top of the expected loop suppression. To correctly explain neutrino masses, therefore large Yukawa couplings are needed in these models. We calculate charged lepton flavor violating observables and find that the three minimal models survive the current constraints only in very narrow regions of their parameter spaces.

scholarly journals Retraction of the paper entitled “Lepton number violation in a unified framework“

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Apriadi Salim Adam ◽  
Yuta Kawamura ◽  
Yamato Matsuo ◽  
Takuya Morozumi ◽  
Yusuke Shimizu ◽  
...  
Keyword(s):  
Mass Function ◽  
Lepton Number ◽  
Primordial Black Hole ◽  
Unified Framework ◽  
Extra Condition ◽  
Formal Expression ◽  
Lepton Number Violation ◽  
Standard Criterion ◽  
New Criterion ◽  
New Formula

Abstract Computations of the primordial black hole (PBH) mass function discussed in the literature have conceptual issues. They stem from the fact that the mass function is a differential quantity and the standard criterion of the PBH formation from the seed primordial fluctuations cannot be directly applied to the computation of the differential quantities. We propose a new criterion of the PBH formation, which is the addition of one extra condition to the existing one. By doing this, we derive a formal expression of the PBH mass function without introducing any ambiguous interpretations that exist in the previous studies. Once the underlying primordial fluctuations are specified, the PBH mass function can be in principle determined by the new formula. As a demonstration of our formulation, we compute the PBH mass function analytically for the case where the perturbations are Gaussian and the space is 1 dimension.

scholarly journals Using Matrix-Product States for Open Quantum Many-Body Systems: Efficient Algorithms for Markovian and Non-Markovian Time-Evolution

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 984
Author(s):  
Regina Finsterhölzl ◽  
Manuel Katzer ◽  
Andreas Knorr ◽  
Alexander Carmele
Keyword(s):  
Time Evolution ◽  
Nearest Neighbor ◽  
Matrix Product ◽  
Body System ◽  
Many Body ◽  
Initial State ◽  
Matrix Product States ◽  
Open Quantum ◽  
Many Body Systems ◽  
The Many

This paper presents an efficient algorithm for the time evolution of open quantum many-body systems using matrix-product states (MPS) proposing a convenient structure of the MPS-architecture, which exploits the initial state of system and reservoir. By doing so, numerically expensive re-ordering protocols are circumvented. It is applicable to systems with a Markovian type of interaction, where only the present state of the reservoir needs to be taken into account. Its adaption to a non-Markovian type of interaction between the many-body system and the reservoir is demonstrated, where the information backflow from the reservoir needs to be included in the computation. Also, the derivation of the basis in the quantum stochastic Schrödinger picture is shown. As a paradigmatic model, the Heisenberg spin chain with nearest-neighbor interaction is used. It is demonstrated that the algorithm allows for the access of large systems sizes. As an example for a non-Markovian type of interaction, the generation of highly unusual steady states in the many-body system with coherent feedback control is demonstrated for a chain length of N=30.

scholarly journals A SOLUTION TO THE STRONG CP PROBLEM TRANSFORMING THE THETA ANGLE TO THE KM CP-VIOLATING PHASE

2010 ◽  
Vol 25 (32) ◽  
pp. 5897-5911 ◽  
Author(s):  
JOSÉ BORDES ◽  
HONG-MO CHAN ◽  
SHEUNG TSUN TSOU
Keyword(s):  
Mass Matrix ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Order Unity ◽  
Ckm Matrix ◽  
Cp Violations ◽  
Fermion Mass Matrix

It is shown that in the scheme with a rotating fermion mass matrix (i.e. one with a scale-dependent orientation in generation space) suggested earlier for explaining fermion mixing and mass hierarchy, the theta angle term in the QCD action of topological origin can be eliminated by chiral transformations, while giving still nonzero masses to all quarks. Instead, the effects of such transformations get transmitted by the rotation to the CKM matrix as the KM phase giving, for θ of order unity, a Jarlskog invariant typically of order 10-5, as experimentally observed. Strong and weak CP violations appear then as just two facets of the same phenomenon.

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