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See detailLeptogenesis in the presence of exact flavor symmetries
Aristizabal Sierra, Diego ULg; Bazzocchi, Federica

in Journal of High Energy Physics [=JHEP] (2012)

In models with flavor symmetries in the leptonic sector leptogenesis can take place in a very different way compared to the standard leptogenesis scenario. We study the generation of a B−L asymmetry in ... [more ▼]

In models with flavor symmetries in the leptonic sector leptogenesis can take place in a very different way compared to the standard leptogenesis scenario. We study the generation of a B−L asymmetry in these kind of models in the flavor symmetric phase pointing out that successful leptogenesis requires (i) the right-handed neutrinos to lie in different irreducible representations of the flavor group; (ii) the flavons to be lighter at least that one of the right-handed neutrino representations. When these conditions are satisfied leptogenesis proceeds due to new contributions to the CP violating asymmetry and — depending on the specific model — in several stages. We demonstrate the validity of these arguments by studying in detail the generation of the B − L asymmetry in a scenario of a concrete A 4 flavor model realization. [less ▲]

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See detailLeptogenesis with a dynamical seesaw scale
Aristizabal Sierra, Diego ULg; Tortola, Maria; Valle, Jose et al

in Journal of Cosmology and Astroparticle Physics [= JCAP] (2014), 2014

In the simplest type-I seesaw leptogenesis scenario right-handed neutrino annihilation processes are absent. However, in the presence of new interactions these processes are possible and can affect the ... [more ▼]

In the simplest type-I seesaw leptogenesis scenario right-handed neutrino annihilation processes are absent. However, in the presence of new interactions these processes are possible and can affect the resulting B-L asymmetry in an important way. A prominent example is provided by models with spontaneous lepton number violation, where the existence of new dynamical degrees of freedom can play a crucial role. In this context, we provide a model-independent discussion of the effects of right-handed neutrino annihilations. We show that in the weak washout regime, as long as the scattering processes remain slow compared with the Hubble expansion rate throughout the relevant temperature range, the efficiency can be largely enhanced, reaching in some cases maximal values. Moreover, the B-L asymmetry yield turns out to be independent upon initial conditions, in contrast to the ''standard'' case. On the other hand, when the annihilation processes are fast, the right-handed neutrino distribution tends to a thermal one down to low temperatures, implying a drastic suppression of the efficiency which in some cases can render the B-L generation mechanism inoperative. [less ▲]

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See detailLepton Flavor Equilibration and Leptogenesis
Aristizabal Sierra, Diego ULg; Losada, Marta; Enrico, Nardi

in Journal of Cosmology and Astroparticle Physics [= JCAP] (2009), 0912

We study the role played in leptogenesis by the equilibration of lepton flavors, as could be induced in supersymmetric models by off diagonal soft breaking masses for the scalar lepton doublets mαβ, or ... [more ▼]

We study the role played in leptogenesis by the equilibration of lepton flavors, as could be induced in supersymmetric models by off diagonal soft breaking masses for the scalar lepton doublets mαβ, or more generically by new sources of lepton flavor violation. We show that if mαβ>1GeV and leptogenesis occurs below ~100TeV, dynamical flavor effects are irrelevant and leptogenesis is correctly described by a one-flavor Boltzmann equation. We also discuss spectator effects in low scale leptogenesis by taking into account various chemical equilibrium conditions enforced by the reactions that are in thermal equilibrium. We write down the Boltzmann equation for low scale supersymmetric leptogenesis that includes flavor and spectator effects in the presence of lepton flavor equilibration, and we show how it reduces to a particularly simple form. [less ▲]

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See detailLepton flavor violation and seesaw symmetries
Aristizabal Sierra, Diego ULg

in Hyperfine Interactions (2013, February), 214

When the standard model is extended with right-handed neutrinos the symmetries of the resulting Lagrangian are enlarged with a new global U(1)R Abelian factor. In the context of minimal seesaw models we ... [more ▼]

When the standard model is extended with right-handed neutrinos the symmetries of the resulting Lagrangian are enlarged with a new global U(1)R Abelian factor. In the context of minimal seesaw models we analyze the implications of a slightly broken U(1)R symmetry on charged lepton flavor violating decays. We find, depending on the R-charge assignments, models where charged lepton flavor violating rates can be within measurable ranges. In particular, we show that in the resulting models due to the structure of the light neutrino mass matrix muon flavor violating decays are entirely determined by neutrino data (up to a normalization factor) and can be sizable in a wide right-handed neutrino mass range. [less ▲]

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See detailLepton flavor violation in low-scale seesaw models: SUSY and non-SUSY contributions
Krauss, Manuel E.; Porod, Werner; Staub, Florian et al

in Journal of High Energy Physics [=JHEP] (2014), 1411

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See detailLepton flavor violation in SUSY left-right symmetric theories
Vicente, Avelino ULg

in Journal of Physics: Conference Series (2010), 259

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See detailLepton Flavor Violation in the Scotogenic Model
Toma, Takashi; Vicente, Avelino ULg

in Journal of High Energy Physics [=JHEP] (2014), 1401

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See detailLeptonic Charged Higgs Decays in the Zee Model
Aristizabal Sierra, Diego ULg; Restrepo, Diego

in Journal of High Energy Physics [=JHEP] (2006), 0608

We consider the version of the Zee model where both Higgs doublets couple to leptons. Within this framework we study charged Higgs decays. We focus on a model with minimal number of parameters consistent ... [more ▼]

We consider the version of the Zee model where both Higgs doublets couple to leptons. Within this framework we study charged Higgs decays. We focus on a model with minimal number of parameters consistent with experimental neutrino data. Using constraints from neutrino physics we (i) discuss the reconstruction of the parameter space of the model using the leptonic decay patterns of both of the two charged Higgses, h(1,2)→ℓj+νi, and the decay of the heavier charged Higgs, h2→h1+h0; (ii) show that the decay rate Γ(h1→μ+νi) in general is enhanced in comparision to the standard two Higgs doublet model while in some regions of parameter space Γ(h1→μ+νi) even dominates over Γ(h1→τ+νi). [less ▲]

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See detailLeptoquarks: Neutrino masses and accelerator phenomenology
Aristizabal Sierra, Diego ULg; Hirsch, M.; S.G., Kovalenko

in Physical Review. D : Particles and Fields (2008), 77

Leptoquark-Higgs interactions induce mixing between leptoquark states with different chiralities once the electro-weak symmetry is broken. In such LQ models Majorana neutrino masses are generated at 1 ... [more ▼]

Leptoquark-Higgs interactions induce mixing between leptoquark states with different chiralities once the electro-weak symmetry is broken. In such LQ models Majorana neutrino masses are generated at 1-loop order. Here we calculate the neutrino mass matrix and explore the constraints on the parameter space enforced by the assumption that LQ-loops explain current neutrino oscillation data. LQs will be produced at the LHC, if their masses are at or below the TeV scale. Since the fermionic decays of LQs are governed by the same Yukawa couplings, which are responsible for the non-trivial neutrino mass matrix, several decay branching ratios of LQ states can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and τ final states are expected. In addition, the model predicts that, if kinematically possible, heavier LQs decay into lighter ones plus either a standard model Higgs boson or a Z0/W± gauge boson. Thus, experiments at the LHC might be able to exclude the LQ mechanism as explanation of neutrino data. [less ▲]

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See detailLeptospira spp. prevalence in small mammal populations in Cotonou, Benin
Houemenou, Gualbert ULg; Ahmed, A.; Libois, Roland ULg et al

in ISRN Epidemiology (2013)

The aim of this study was to assess the Leptospira prevalence in small animals in Cotonou, the capital of Benin. Rodents and shrews were captured in urban and periurban settings and determined as species ... [more ▼]

The aim of this study was to assess the Leptospira prevalence in small animals in Cotonou, the capital of Benin. Rodents and shrews were captured in urban and periurban settings and determined as species of the genera Rattus, Mastomys, and Crocidura. Kidney specimens of 90 animals were examined using a real-time PCR assay specific for leptospires that belong to pathogenic species. Leptospiral DNA was amplified from kidney tissues ranging from 13.3% (8/60) in Rattus rattus to 100.0% (1/1) in Crocidura spp. with an average of 18.9% (17/90) of the animals caught at 15 locations. Clade-specific Taqman PCR on 10 samples placed six of these within clade 1 comprising the species L. kirschneri, L. interrogans, L. meyeri, and L. noguchii and four within clade 2 consisting of species L. weilii, L. alexanderi, L. borgpetersenii, and L. santarosai. Phylogenetic analysis of partial sequences of the amplicons of seven samples of these 10 samples revealed that four of the clade 1 samples could equally be assigned to L. interrogans and L. kirschneri and three samples fromclade 2 belonged to L. borgpetersenii. Results presented in the paper indicate that small mammals present a major public health risk for acquiring leptospirosis in Cotonou, Benin and will contribute to a raised awareness amongst health care workers and decision makers and hence promote appropriate clinical management of cases. [less ▲]

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See detailLa leptospirose du chien : actualités d'une vieille maladie
Mainil, Jacques ULg

Scientific conference (2008, April)

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See detailLernen lebender Fremdsprachen an den Schulen der europaïschen Union
Blondin, Christiane ULg

Book published by Amt für amtliche Veröffentlichungen der Europaïschen Gemeinschaften (1997)

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See detailLernout & Hauspie, Neuroplanet, SABENA ... ou quand les rêves indomptés s’écrasent contre les murs de la réalité
Van Caillie, Didier ULg

Article for general public (2002)

This chronicle analyses the reasons for some important recent firm failures in Belgium and insists on the crucial role played by growth management in the evolution of the firm

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See detailLeroi-Gourhan, l'art, la pensée et la main
de Villers Grand Champs, Bénédicte ULg

Conference given outside the academic context (2013)

Detailed reference viewed: 27 (7 ULg)
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See detailLe lérot: Eliomys quercinus
Libois, Roland ULg

Learning material (1994)

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See detailLe lérot: trois études en une enquête
Libois, Roland ULg

Learning material (2003)

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