Clemens P. Kiessig, Michael Plumacher
We investigate the validity of using thermal masses in the kinematics of final states in the decay rate of heavy neutrinos in leptogenesis calculations. We find that using thermal masses this way is a reasonable approximation, but corrections arise through quantum statistical distribution functions and leptonic quasiparticles.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
继续探索
I discuss the connection between neutrino masses and leptogenesis. I use three prime examples: (1) canonical seesaw, (2) triplet Higgs, and (3) $R$ parity violation.
We present a TeV scale model for leptogenesis where the origin of neutrino masses are independent of the scale of leptogenesis. As a result, the model could be extended to explain {\it dark matter, neutrino masses and leptogenesis at the TeV scale}. The most attractive feature of this model is that it predicts a few hundred GeV triplet Higgs scalar that can be tested at LHC or ILC.
This paper has been withdrawn by the author due to a crucial sign error.
In the supersymmetric extensions of the standard model, neutrino masses and leptogenesis requires existence of new particles. We point out that if these particles with lepton number violating interactions have standard model gauge interactions, then they may not be created after reheating because of the gravitino problem. This will rule out all existing models of neutrino masses and leptogenesis, except the one with right-handed singlet neutrinos.
Upper bounds on the CP asymmetry relevant for leptogenesis are reexamined and found weaker than in previous literature, both for hierarchical and for quasi-degenerate right-handed neutrinos. Successful leptogenesis implies the usual lower bound on right-handed neutrino masses, and an upper bound on left-handed neutrino masses (which we obtain to be 0.15eV at 3sigma) only if right-handed neutrinos are assumed to be much more hierarchical than left-handed neutrinos. Otherwise both bounds can be considerably relaxed. The constraint on light neutrino masses varies assuming different interpretation…
We construct a supersymmetric version of the triplet Higgs model for neutrino masses, which can generate a baryon asymmetry of the Universe through lepton-number violation and is consistent with the gravitino constraints.
We prove that taking correctly into account the lepton flavour dependence of the CP asymmetries and washout processes, it is possible to obtain successful thermal leptogenesis from the decays of the second right-handed neutrino. The asymmetries in the muon and tau-flavour channels are then not erased by the inverse decays of the lightest right-handed neutrino, N_1. In this way, we reopen the possibility of ``thermal leptogenesis'' in models with a strong hierarchy in the right-handed Majorana masses that is typically the case in models with up-quark--neutrino Yukawa unification.
A simple and economical extension of the minimal standard electroweak gauge model (without right-handed neutrinos) by the addition of two heavy Higgs scalar triplets would have two significant advantages. \underline {Naturally} small Majorana neutrino masses would become possible, as well as leptogenesis in the early universe which gets converted at the electroweak phase transition into the present observed baryon asymmetry.
We investigate baryogenesis via leptogenesis and generation of neutrino masses and mixings through the Type I plus Type III seesaw plus an one-loop mechanism in the context of Renormalizable Adjoint SU(5) theory. One light neutrino remains massless, because the contributions of three heavy Majorana fermions ρ_0, ρ_3 and ρ_8 to the neutrino mass matrix are not linearly independent. However none of these heavy fermions is decoupled from the generation of neutrino masses. This opens a new range in parameter space for successful leptogenesis, in particular, allows for inverted hierarchy of the neu…
We address the issue of the neutrino masses and mixing in TeV scale $B-L$ extension of the Standard Model. We show that if Dirac neutrino masses are of order $10^{-4}$ Gev, then the measured neutrino masses are correctly obtained. We propose a mass relation between quarks and leptons that may account for such small Dirac neutrino masses. We analyze the leptogenesis in this type of models and provide analytical expressions for the new contributions due to the predicted extra Higgs and extra neutral gauge boson. We find that thermal leptogenesis, with a resonant enhancement due to nearly degener…
In R parity violating supersymmetry (conserving baryon number B but violating lepton number L), Majorana neutrino masses may arise at tree level, in one loop, and in two loops. The L violating interactions work together with the B + L violating electroweak sphalerons to erase any preexisting B or L asymmetry of the Universe. To have successful leptogenesis nevertheless, a specific scenario is proposed.
Thermal leptogenesis is an attractive mechanism for generating the baryon asymmetry of the Universe. However, in supersymmetric models, the parameter space is severely restricted by the gravitino bound on the reheat temperature $T_{RH}$. Using a parametrisation of the seesaw in terms of weak-scale inputs, the low-energy footprints of thermal leptogenesis are discussed.
Models with composite singlet neutrinos can give small Majorana or Dirac masses to the active neutrinos. The mechanism is based on the fact that conserved chiral symmetries give massless neutrinos at the renormalizable level. Thus, they acquire very small masses due to non-renormalizable terms. We investigate such models in two aspects. First, we find UV completions for them and then we investigate the possibility of giving leptogenesis. We find that these models offer new possibilities for leptogenesis. Models with Majorana masses can exhibit standard leptogenesis. Models with Dirac masses ca…
We obtain model independent relations among neutrino masses and leptogenesis parameters. We find exact relations that involve the CP asymmetries $ε_{N_α}$, the washout parameters $\tilde m_α$ and $θ_{αβ}$, and the neutrino masses $m_i$ and $M_α$, as well as powerful inequalities that involve just $\tilde m_α$ and $m_i$. We prove that the Yukawa interactions of at least two of the heavy singlet neutrinos are in the strong washout region ($\tilde m_α\gg10^{-3} eV$).
The minimal Type I see-saw model cannot explain the observed neutrino masses and the baryon asymmetry of the Universe via hierarchical thermal leptogenesis without ceding naturalness. We show that this conclusion can be avoided by adding a second Higgs doublet with $\tanβ\gtrsim 4$. The models considered naturally accommodate a SM-like Higgs boson, and predict TeV-scale scalar states and low- to intermediate-scale hierarchical leptogenesis with $10^3\text{ GeV}\lesssim M_{N_1}\lesssim 10^8\text{ GeV}$.
In the supersymmetric standard model of particle interactions, R-parity nonconservation is often invoked to obtain nonzero neutrino masses. We point out here that such interactions of the supersymmetric particles would erase any pre-existing lepton or baryon asymmetry of the universe before the electroweak phase transition through the $B + L$ violating sphaleron processes. We then show how neutrino masses may be obtained in supersymmetry (assuming R-parity conservation) together with successful leptogenesis and predict the possible existence of new observable particles.
We propose a model with an $U(1)_{B-L}$ gauge symmetry, in which small neutrino masses, dark matter and the matter-antimatter asymmetry in the Universe can be simultaneously explained. In particular, the neutrino masses are generated radiatively, while the matter-antimatter asymmetry is led by the leptogenesis mechanism, at TeV scale. We also explore allowed regions of the model parameters and discuss some phenomenological effects including lepton flavor violating processes.
In this work we use previous results on the masses and mixing of neu- trinos of an S3 model with three right-handed Majorana neutrinos and three Higgs doublets, to reduce one parameter in the case when two of the right-handed neutrinos are mass degenerate. We derive a new param- eterization for the VP M N S mixing matrix, with a new set of parameters, in the more general case where the right-handed neutrino masses are dif- ferent. With these results, we calculate leptogenesis and the associated baryogenesis in the model in the two different scenarios. We show that it is possible to have enough…
Observational evidences of nonzero neutrino masses and the existence of dark matter request physics beyond standard model. A model with extra scalars and leptonic vector-like fermions is introduced. By imposing a Z_2 symmetry, the neutrino masses as well as anomalous muon magnetic moment can be generated via one-loop effects at TeV-scale. An effort of explaining dark matter, Lithium problem, and leptogenesis is presented. This scenario can be tested at LHC and/or future experiments.
We study a seesaw-type extension of the Standard Model in which the symmetry group is enlarged by a global U(1). We introduce adequate scalar and fermion representations which naturally explain the smallness of neutrino masses. With the addition of a viable scalar Dark Matter candidate, an original scenario of leptogenesis emerges. We solve the relevant set of Boltzmann equations and show how leptogenesis can be successfully implemented at the TeV scale. The constraints on the scalar mass spectrum are derived and the Dark Matter phenomenology is discussed.
We study the baryogenesis via leptogenesis in a class of left-right symmetric models, in which $D$-parity is broken spontaneously. We first discuss the consequence of the spontaneous $D$-parity breaking on the neutrino masses. Than we study the lepton asymmetry in various cases, from the decay of right handed neutrino as well as the triplet Higgs, depending on their relative masses they acquire from the symmetry breaking pattern. The leptogenesis bound on their masses are discussed by taking into account the low energy neutrino oscillation data. It is shown that a TeV scale leptogenesis is via…
Thermal leptogenesis, that can be viewed as a consequence of the seesaw model, is a very natural mechanism to explain the matter anti-matter asymmetry of the Universe. Recently, lepton flavours have been included in the Boltzmann equations, modifying significantly the evaluation of the efficiency of leptogenesis to explain the observed baryon asymmetry.
The paper suggests a left-right mirror symmetric model with the flavor symmetries $Z_{3L}\otimes Z_{3R}$. It can simultaneously accommodate the standard model, neutrino physics and the baryon asymmetry. The fermion masses and $CP$ violation originate from vacuum spontaneous breaking of the flavor field. The baryon asymmetry is implemented through the leptogenesis which is related to the lepton $CP$ violation. The model can naturally and correctly reproduce all kinds of experimental data, in particular, all of the values of the fermion masses and mixings are accurately fitted by the fewer param…
Minimal effective theory for leptogenesis, dark matter, and neutrino masses
本文提出一种最小有效算符框架，仅借助一个重不稳定费米子和一个轻暗物质标量，即可同时解释暗物质遗迹密度、物质-反物质不对称性及中微子质量。
We propose an interesting model of neutrino masses to realize leptogenesis and dark matter at the TeV scale. A real scalar is introduced to naturally realize the Majorana masses of the right-handed neutrinos. We also include a new Higgs doublet that contributes to the dark matter of the universe. The neutrino masses come from the vacuum expectation value of the triplet Higgs scalar. The right-handed neutrinos are not constrained by the neutrino masses and hence they could generate leptogenesis at the TeV scale without subscribing to resonant leptogenesis. In our model, all new particles could …
It is well-known that leptogenesis in low energy scale is difficult in the conventional Type-I seesaw mechanism with hierarchical right-handed neutrino masses. We show that in a class of two Higgs doublet model, where one Higgs doublet generates masses of quarks and charged leptons whereas the other Higgs doublet with a tiny vacuum expectation value generates neutrino Dirac masses, large Yukawa couplings lead to a large enough CP asymmetry of the right-handed neutrino decay. Thermal leptogenesis suitably works at low energy scale as keeping no enhancement of lepton number violating wash out ef…
Thermal leptogenesis in the canonical seesaw model in supersymmetry suffers from the incompatibility of a generic lower bound on the mass scale of the lightest right-handed neutrino and the upper bound on the reheating temperature of the Universe after inflation. This is resolved by adding an extra singlet superfield, with a discrete $Z_2$ symmetry, to the NMSSM (Next to Minimal Supersymmetric Standard Model). This generic mechanism is applicable to any supersymmetric model for lowering the scale of leptogenesis.
We study the thermal leptogenesis in a hybrid model, which combines the so called split fermion model and the bulk neutrino model defined in five dimensional spacetime. This model predicts the existence of a heavy neutrino pair nearly degenerate in mass, whose decays might generate a CP violation large enough for creating the baryon asymmetry of the universe through leptogenesis. We investigate numerically the constraints this sets on the parameters of the model such as the size of the compactified fifth dimension.
Leptogenesis is considered in its natural context where Majorana neutrinos fit in a gauge unification scheme and therefore couple to some extra gauge bosons. The masses of some of these gauge bosons are expected to be similar to those of the heavy Majorana particles, and this can have important consequences for leptogenesis. In fact, the effect can go both ways. Stricter bounds are obtained on one hand due to the dilution of the CP-violating effect by new decay and scattering channels, while, in a re-heating scheme, the presence of gauge couplings facilitates the re-population of the Majorana …
We suggest a hybrid seesaw model where relatively ``light''right-handed neutrinos give no contribution to the neutrino mass matrix due to a special symmetry. This allows their Yukawa couplings to the standard model particles to be relatively strong, so that the standard model Higgs boson can decay dominantly to a left and a right-handed neutrino, leaving another stable right-handed neutrino as cold dark matter. In our model neutrino masses arise via the type-II seesaw mechanism, the Higgs triplet scalars being also responsible for the generation of the matter-antimatter asymmetry via the lepto…
In the present work we discuss baryon asymmetry in the non-thermal leptogenesis scenario and gravitino cosmology for an unstable gravitino with inflaton decay. We take into account two production mechanisms for gravitino, namely thermal production and inflaton decay. We wish to show in plots the allowed parameter space so that the BBN constraint and the requirement for the right baryon asymmetry are satisfied at the same time. However our analysis shows that it is impossible to achieve both goals simultaneously.
Assuming the Dirac-type neutrino masses m_D are related to quark or charged lepton masses, neutrino oscillation data indicate that right handed neutrino masses are in general strongly hierarchical. In particular, if m_D is similar to the up-type quark masses, the mass of the lightest right handed neutrino M_1<~10^6 GeV. We show that non-thermal leptogenesis by inflaton decay can yield sufficient baryon asymmetry despite this constraint, and discuss how the asymmetry is correlated with the low energy neutrino masses and CP-violating phases.
We make a simple observation that if one of the right-chiral neutrinos is very heavy or its Yukawa couplings to the standard lepton doublets are negligible, so that it effectively decouples from the see-saw mechanism, the prediction for the baryon asymmetry of the Universe resulting from leptogenesis depends, apart from the masses $M_1$ and $M_2$ of the remaining two right-chiral neutrinos, only on the element $\YY{22}$ of the neutrino Yukawa coupling. For $M_2\simgt10M_1$ the lower bound on $M_1$ and also on $T_{\rm reh}$, resulting from the requirement of 'successful leptogenesis' is then si…
We propose a unified explanation for the origin of dark matter and baryon number asymmetry on the basis of a non-supersymmetric model for neutrino masses. Neutrino masses are generated in two distinct ways, that is, a tree-level seesaw mechanism with a single right-handed neutrino, and one-loop radiative effects by a new additional doublet scalar. A spontaneously broken U(1)$^\prime$ brings a $Z_2$ symmetry which restricts couplings of this new scalar and controls the neutrino masses. It also guarantees the stability of a CDM candidate. We examine two possible candidate for the CDM. We also sh…
We reconsidered leptogenesis scenario from right-handed (s)neutrino produced by the decay of inflaton. Besides the well-investigated case that the neutrino decays instantaneously after the production, leptogenesis is possible if neutrino decays after it dominates the universe. In the latter case, right-handed (s)neutrino can decay either while it is relativistic or after it becomes non-relativistic. Especially, the first case has not been discussed seriously in literatures. Resultant lepton asymmetry and constraints from the gravitino problem are studied in broad parameter region, including al…
In the present work we study non-thermal leptogenesis and baryon asymmetry in the universe in different neutrino mass models discussed recently. For each model we obtain a formula relating the reheating temperature after inflation to the inflaton mass. It is shown that all but four cases are excluded and that in the cases which survive the inflaton mass and the reheating temperature after inflation are bounded from below and from above.
In the present work we study both thermal and non-thermal leptogenesis in all neutrino mass models describing the presently available neutrino mass patterns. We consider the Majorana CP violating phases coming from right-handed Majorana mass matrices to estimate the baryon asymmetry of the universe, for different neutrino mass models namely degenerate, inverted hierarchical and normal hierarchical models, with tribimaximal mixings. Considering two possible diagonal forms of Dirac neutrino mass matrix as either charged lepton or up-quark mass matrix, the right-handed Majorana mass matrices are …
We discuss leptogenesis in the light of indications of neutrino masses and mixings from Super-Kamiokande and other data on atmospheric neutrinos, as well as the solar neutrino deficit. Neutrino masses and mixings consistent with these data may produce in a natural and generic way a lepton asymmetry that is suffient to provide the observed baryon asymmetry, after processing via non-perturbative electroweak effects. We illustrate this discussion in the framework of the string-derived flipped SU(5) model, using particle assignments and choices of vacuum parameters that are known to give realistic…
We consider a smooth hybrid inflation scenario based on a supersymmetric SU(2)_L x SU(2)_R x U(1)_B-L model. The Higgs triplets involved in the model play a key role in inflation as well as in explaining the observed baryon asymmetry of the universe. We show that the baryon asymmetry can originate via non-thermal triplet leptogenesis from the decay of SU(2)_L triplets, whose tiny vacuum expectation values also provide masses for the light neutrinos.
We study a simple extension of the standard model to simultaneously explain neutrino masses, dark matter and the matter-antimatter asymmetry of the Universe. In our model, the baryon asymmetry is achieved by the leptogenesis mechanism, while the decaying dark matter with the lifetime of O(10^26 s) provides a natural solution to the electron and positron excesses in Fermi and PAMELA satellite experiments. In particular, we emphasize that our model is sensitive to the structure at the endpoint around 1 TeV of the Fermi data. In addition, some of new particles proposed in the model are within the…
We consider an extended supersymmetric SO(10) seesaw model with only doublet Higgs scalars, in which neutrino masses are suppressed by the scale of D-parity violation. Leptogenesis can occur at the TeV scale through the decay of a singlet Sigma, thereby avoiding the gravitino crisis. Washout of the asymmetry can be effectively suppressed by the absence of direct couplings of Sigma to leptons.
We extend the standard model by three types of inert fields including Majorana fermion singlets/triplets, real Higgs singlets/triplets and leptonic Higgs doublets. In the presence of a softly broken lepton number and an exactly conserved Z_2 discrete symmetry, these inert fields together can mediate a one-loop diagram for a Majorana neutrino mass generation. The heavier inert fields can decay to realize a successful leptogenesis while the lightest inert field can provide a stable dark matter candidate. As an example, we demonstrate the leptogenesis by the inert Higgs doublet decays. We also pe…
We propose a model with $D_4$ flavor symmetry for leptogenesis in the framework of supersymmetric $SU(5)$ grand unified theory. Neutrino masses arise from the type I seesaw mechanism where the spontaneous symmetry breaking of the flavor symmetry leads to the well-known trimaximal mixing ($TM_2$). We find that this model predicts the normal hierarchy (NH) for neutrino masses. We also find that the predicted range of the effective neutrino mass $m_{ββ}$ can be tested at future neutrinoless double beta decay experiments. For the generation of the baryon asymmetry of the Universe (BAU), we conside…
Seven types of leptogenesis models which can lead to a successful explanation of baryogenesis are presented. Emphasis is put on the conditions which need to be fulfilled by the neutrino masses as well as by the heavy state masses. The model dependence of these conditions is discussed.
Properties of neutrinos may be the origin of the matter-antimatter asymmetry of the universe. In the seesaw model for neutrino masses this leads to important constraints on the properties of light and heavy neutrinos. In particular, an upper bound on the light neutrino masses of 0.1 eV can be derived. We review the present status of thermal leptogenesis with emphasis on the theoretical uncertainties and discuss some implications for lepton and quark mass hierarchies, CP violation and dark matter. We also comment on the `leptogenesis conspiracy', the remarkable fact that neutrino masses may lie…
The presence of the triplet $Δ_{L}$ in left-right symmetric theories leads to type-II see-saw mechanism for the neutrino masses. In these models, assuming a normal mass hierarchy for the heavy Majorana neutrinos, we derive a lower bound on the mass of the lightest of heavy Majorana neutrino from the leptogenesis constraint. From this bound we establish a consistent picture for the hierarchy of heavy Majorana neutrinos in a class of left right symmetric models in which we identify the neutrino Dirac mass matrix with that of Fritzsch type charged lepton mass matrix. It is shown that these values…
Economical extensions of the Standard Model (SM), in which the famous Davidson-Ibarra bound on the CP asymmetry relevant for leptogenesis may be significantly relaxed by the loop effects, comparing to predictions of the SM extended only by right-handed neutrinos with hierarchical masses, are discussed. This leads to decreasing of the lower bound on the heavy neutrino masses and increasing of the upper bound on the light neutrino masses. In addition, the considered theory may help to solve the dark matter problem.
Under the assumption of hierarchical right-handed neutrino masses, masses of right-handed neutrinos must be larger than $10^8$ GeV in the standard thermal leptogenesis scenario, while the mass can be reduced to around 5 TeV in a neutrinophilic two Higgs doublet model. On the other hand, resonant leptogenesis can work with the masses of TeV-scale. However, necessary degeneracy between the lightest and the second lightest right-handed neutrino masses means unnatural fine-tuning of the order of $10^9$. In this paper, we will investigate the resonant leptogenesis scenario in a neutrinophilic two H…
We investigated thermal leptogenesis scenarios in the left-right symmetric extension of the standard model. In the SO(10) GUT framework, we impose the D-parity realization below GUT scale. These two conditions makes our model more restrictive and predictive. In such a case, a D-parity odd singlet in the 4-index antisymmetric tensor representation of SO(10) have a critical role. This singlet have prospects of causing a very large mass hierarchy between SU(2)L and SU(2)R triplet scalars. We test our model by computing baryogenesis via leptogenesis. The heavy right-handed neutrinos N's and the SU…
A one-flavour naturalness argument suggests that the Type I seesaw model cannot naturally explain neutrino masses and the baryon asymmetry of the Universe via hierarchical thermal leptogenesis. We prove that there is no way to avoid this conclusion in a minimal three-flavour setup. We then comment on the simplest ways out. In particular, we focus on a resolution utilising a second Higgs doublet. Such models predict an automatically SM-like Higgs boson, (maximally) TeV-scale scalar states, and low- to intermediate-scale hierarchical leptogenesis with $10^3\text{ GeV}\lesssim M_{N_1}\lesssim 10^…
The mechanism of thermal leptogenesis is investigated in the high-energy regime of braneworld cosmology. Within the simplest seesaw framework with hierarchical heavy Majorana neutrinos, we study the implications of the modified Friedmann equation on the realization of this mechanism. In contrast with the usual leptogenesis scenario of standard cosmology, where low-energy neutrino data favors a mildly strong washout regime, we find that leptogenesis in the braneworld regime is successfully realized in a weak washout regime. Furthermore, a quasi-degenerate light neutrino mass spectrum is found t…
The left-right symmetric model with doublet and bi-doublet Higgs scalars can accommodate linear, inverse or double seesaw for generating small neutrino masses in the presence of three singlet fermions. If the singlet fermions have small Majorana masses, they can form three pairs of quasi-degenerate Majorana fermions with three right-handed neutrinos. The decays of the quasi-degenerate Majorana fermions can realize the resonant leptogenesis. Alternatively, the right-handed neutrinos can obtain seesaw suppressed Majorana masses if the singlet fermions are very heavy. In this case leptogenesis, w…
We study the thermal leptogenesis in the scenario where the standard model is extended to include one $SU(2)_{L}$ triplet Higgs boson, in addition to three generations of the right-handed neutrinos. And in the model we introduce the coupling between the Quintessence and the right-handed neutrinos, the triplet Higgs boson, so that the light neutrino masses vary during the evolution of the universe. Assuming that the lepton number asymmetry is generated by the decays of the lightest right-handed neutrino $N_{1}$, we find the thermal leptogenesis can be characterized by four model independent par…
We consider a model of dynamical neutrino masses via the see-saw mechanism. Nambu-Goldstone bosons (majorons) arise associated with the formation of the heavy right-handed majorana masses. These bosons then acquire naturally soft masses (become pNGB's) at loop level via the Higgs-Yukawa mass terms. These models, like the original neutrino pNGB quintessence schemes of the 1980's that proceed through the Dirac masses, are natural, have cosmological implications through mass varying neutrinos, long range forces, and provide a soft potential for dark energy. We further argue that these models can …
In the conventional seesaw models of neutrino masses, leptogenesis occurs at a very high scale. Three approaches have been discussed in the literature to lower the scale of leptogenesis: mass degeneracy, hierarchy of couplings and three-body decays. We advocate yet another approach to a testable leptogenesis, whereby the decaying particles could go out of equilibrium at an accessible scale due to kinematics, although their couplings to the decay products are larger for generating a desired CP asymmetry. We demonstrate this new possibility for the testable leptogenesis in a two Higgs doublet mo…
Dominant Thermal Resonant Mechanism for Low-Scale Leptogenesis
本文提出热共振轻子生成机制，通过热激发的共振相干性产生宇宙中子 asymmetry，无需准简并 sterile 中微子共振增强。
We review recent developments in leptogenesis on flavor effects. Their account discloses an important connection between the matter-antimatter asymmetry of the Universe and CP violation at low energies. Besides, they modify the upper bound on the neutrino masses holding in the unflavored case. In this respect, it is important to identify the exact condition for flavor effects to be relevant and for the `fully flavored' Boltzmann equations to be valid.
It is known that the radiative neutrino mass model proposed by Ma could be a consistent framework for dark matter, leptogenesis and suppressed lepton flavor violation if a neutral component of the inert doublet is identified as dark matter and the right-handed neutrinos are of O(10^7) GeV or more. In the same model we explore another scenario such that right-handed neutrinos are in TeV regions and their lightest one is dark matter. It is shown that this scenario requires fine mass degeneracy to generate the appropriate baryon number asymmetry as in the case of resonant leptogenesis. As long as…
Generation of the neutrino masses and leptogenesis (LG) in the Standard Model extended by the heavy Majorana fermions is considered. Classification of LG scenarios according to the new fermion mass spectra is given, where singlet-triplet LG is considered for the first time. The upper bound on the CP asymmetry relevant for LG with hierarchical heavy neutrinos (Davidson-Ibarra bound) is revised, and shown that in the case of one massless neutrino it essentially depends on the type of the light neutrino mass hierarchy. The resonant scenarios, which help to avoid the problem of extremely high rehe…
Thermal leptogenesis, in the seesaw model, is a popular mechanism for generating the Baryon Asymmetry of the Universe. It was noticed recently, that including lepton flavour can modify significantly the results. These proceedings aim to discuss why and when flavour matters, in the thermal leptogenesis scenario for hierarchical right-handed neutrinos. No Boltzmann Equations are introduced.
扫码添加微信好友，提出您的宝贵建议 👇
💡 备注请填写：网站反馈
发表机构由 AI 从论文文本抽取，如发现错误，欢迎反馈修正建议。