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J. -M. Frere

Publications and source records attributed to J. -M. Frere.

At least 19 recordsLinked to original sources
arXiv2013

Neutrino hierarchy and fermion spectrum from a single family in six dimensions: realistic predictions

In this paper, we move from a "proof of concept" to challenging predictions in a flavour model emerging from a single fermion family in six dimensions (6-D) with the two extra dimensions compactified on a sphere. The most striking predictions (beyond the basic ingredients already demonstrated for a realistic quark mass pattern) are for the neutrino sector. Not only can 4-D Majorana masses be generated from 6-D (where no Majorana spinors exist), but Majorana masses are naturally associated to large mixing. The model favours inverted hierarchy and a quasi-Dirac partial suppression of neutrinoless double beta decay.

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arXiv2005

Study of the eta-eta' system in the two mixing angle scheme

An analysis of various decay processes is performed using the two mixing angle description of the $η$-$η^\prime$ system, incorporating the link to the gluonic sector through anomalies. The agreement is excellent. For comparison with previous works, our results are expressed both in the ``octet-singlet'' and in the ``quark-flavour'' basis. It turns out that at the present experimental accuracy, the two angles are significantly different in the former, but not in the latter basis. The implications of our analysis for the Large $N_c$ $χ$PT predictions are also discussed.

hep-ph↗
arXiv2004

Mass and decays of Brout-Englert-Higgs scalar with extra generations

The higher bound on the mass of the Brout-Englert-Higgs scalar boson (BEH boson for brevity) arising from radiative corrections is not stable when the Standard Model is extended to include non-decoupling particles. In particular additional generation{s} of fermions allow for a heavier scalar. We investigate how the decay branchings of scalar boson are affected by the opening of new channels.

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arXiv2004

Flavour violation with a single generation

We calculate probabilities of flavour violating processes mediated by Kalutza-Klein modes of gauge bosons in a model where three generations of the Standard Model fermions arise from a single generation in (5+1) dimensions. We discuss a distinctive feature of the model: while the processes in which the generation number $G$ changes are strongly suppressed, the model is constrained by those with $ΔG=0$, for instance $K\to μ^\pm e^\mp$. The bound on the size of the extra dimensions is $1/R \gtrsim 64$ TeV.

hep-ph↗
arXiv2003

CP violation in weak interactions from orbifold reduction: possible unification structures

We present a mechanism to generate complex phases from real 4+1 dimensional couplings in a model of weak interactions through dimensional reduction of a gauge theory. The orbifolding of a 4+1 dimensional Sp(4) \times U(1) group is the minimal setup which provides both CP violation and an SU(2) \times U(1) structure. We show that grand unification requires at least SO(11).

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arXiv2003

Neutrino Mass Patterns within the See-saw Model from Multi-localization along Extra Dimensions

We study a multi-localization model for charged leptons and neutrinos, including the possibility of a see-saw mechanism. This framework offers the opportunity to allow for realistic solutions in a consistent model without fine-tuning of parameters, even if quarks are also considered. Those solutions predict that the large Majorana mass eigenvalues for right-handed neutrinos are of the same order of magnitude, although this almost common mass can span a large range (bounded from above by $\sim 10^{12}{\rm GeV}$). The model also predicts Majorana masses between $\sim 10^{-2}{\rm eV}$ and $\sim 5 \ 10^{-2}{\rm eV}$ for the left-handed neutrinos, both in the normal and inverted mass hierarchy cases. This mass interval corresponds to sensitivities which are reachable by proposed neutrinoless double $β$ decay experiments. The preferred range for leptonic mixing angle $θ_{13}$ is: $10^{-2} \lesssim \sin θ_{13} \lesssim 10^{-1}$, but smaller values are not totally excluded by the model.

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arXiv2003

Gaugino-induced quark and lepton masses in a truly minimal left-right model

It has recently been proposed that all fundamental fermion masses (whether Dirac or Majorana) come from effective dimension-five operators in the context of a truly minimal left-right model. We show how a particularly economical scheme emerges in a supersymmetric framework, where chiral symmetry breaking originates in the gaugino sector.

hep-ph↗
arXiv2003

Fermions in the vortex background on a sphere

In 5+1 dimensions, we construct a vortex-like solution on a two-dimensional sphere. We study fermionic zero modes in the background of this solution and relate them to the replication of fermion families in the Standard Model. In particular, using a compactified space removes the need for the difficult localisation of gauge fields, while the present procedure (rather than naive compactification on a disk) also removes spurious fermionic modes.

hep-ph↗
arXiv2001

Neutrino masses with a single generation in the bulk

In a class of multidimensional models, topology of the thick brane provides three chiral fermionic families with hierarchical masses and mixings in the effective four-dimensional theory, while the full model contains a single vector-like generation. We discuss how to incorporate three non-degenerate neutrino masses in these models with the help of only one singlet bulk fermion.

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arXiv2001

Insights on neutrino lensing

We discuss the gravitational lensing of neutrinos by astrophysical objects. Unlike photons, neutrinos can cross a stellar core; as a result, the lens quality improves. We also estimate the depletion of the neutrino flux after crossing a massive object and the signal amplification expected. While Uranians alone would benefit from this effect in the Sun, similar effects could be considered for binary systems.

hep-ph↗
arXiv2001

Neutrino suppression and extra dimensions: a minimal model

We study flavour neutrinos confined to our 4-dimensional world coupled to one "bulk" state, i.e. a Kaluza-Klein tower. We discuss the spatial development of the neutrino disappearance, the possibility of resurgence and the effective flavour transitions induced in this mechanism. We show that even a simple model can produce an energy-independent suppression at large distances, and relate this to experimental data.

hep-ph↗
arXiv2000

Three generations on a local vortex in extra dimensions

We develop an approach to the origin of three generations of the Standard Model fermions from one generation in a higher-dimensional theory, where four-dimensional fermions appear as zero modes trapped in the core of a topological defect, and the hierarchy of masses and mixings is produced by wave function overlaps in extra dimensions. We present a model with unbroken U(1) symmetry where three zero modes appear on an Abrikosov-Nielsen-Olesen vortex due to nontrivial scalar--fermion interactions.

hep-ph↗
arXiv1999

Neutrino masses from nonstandard supersymmetry breaking terms

Naturally small Majorana neutrino masses arise from nonstandard supersymmetry breaking terms. This mechanism works in the minimal supersymmetric framework and does not require extra particles or new mass scales. It could also be responsible for proton decay even in the absence of Grand Unification.

hep-ph↗
arXiv1999

Neutrino gravitational lensing

We study the lensing of neutrinos by astrophysical objects. At the difference of photons, neutrinos can cross a stellar core; as a result the lens quality improves. While Saturnians alone would benefit from this effect in the Sun, similar effects could be considered for binary systems.

hep-ph↗
arXiv1999

Anatomy of Mixing-Induced CP Asymmetries in Left-Right-Symmetric Models with Spontaneous CP Violation

We investigate the pattern of CP violation in K, B_d and B_s mixing in a symmetrical SU(2)_R x SU(2)_L x U(1) model with spontaneous CP violation. We calculate the phases of the left and right quark mixing matrices beyond the small phase approximation and perform a careful analysis of all relevant restrictions on the model's parameters from Delta m_K, Delta m_B, epsilon, epsilon'/epsilon and the CP asymmetry in B->J/psi K_S. We find that, with current experimental data, the mass of the right-handed charged gauge boson, M2, is restricted to be in the range 2.75 to 13 TeV and the mass of the flavour-changing neutral Higgs boson, MH, in 10.2 to 14.6 TeV. This means in particular that the decoupling limit M2, MH -> infinity is already excluded by experiment. We also find that the model favours opposite signs of epsilon and sin 2beta and is excluded if sin 2beta > 0.1.

hep-ph↗
arXiv1999

Leptogenesis with virtual Majorana neutrinos

We present a mechanism of leptogenesis based on the out-of-equilibrium decay of a scalar particle into heavy virtual Majorana neutrinos. This scheme presents many conceptual advantages over the conventional scenario of Fukugita and Yanagida. In particular, the standard techniques of quantum field theory can be used to compute the lepton asymmetry, without resorting to the phenomenological approximations usually made to describe unstable particles. This simplification allows us to address in a well-defined framework some issues raised in the recent literature. We also show, in a toy model, that a successful leptogenesis scenario is possible and requires a rather light scalar particle, $10^6 GeV < m < 10^{13} GeV$. A natural embedding of this scheme in a gauged unified theory encompassing the Majorana fermions seems however difficult.

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