Interplay between collective effects and nonstandard interactions of supernova neutrinos

We consider the effect of non-standard neutrino interactions (NSI, for short) on the propagation of neutrinos through the supernova (SN) envelope within a three-neutrino framework and taking into account the presence of a neutrino background. We find that for given NSI parameters, with strength generically denoted by εij, neutrino evolution exhibits a significant time dependence. For |εττ|≳ 10−3 the neutrino survival probability may become sensitive to the θ23 octant and the sign of εττ. In particular, if εττ≳10−2 an internal I-resonance may arise independently of the matter density. For typical values found in SN simulations this takes place in the same dense-neutrino region above the neutrinosphere where collective effects occur, in particular during the synchronization regime. This resonance may lead to an exchange of the neutrino fluxes entering the bipolar regime. The main consequences are (i) bipolar conversion taking place for normal neutrino mass hierarchy and (ii) a transformation of the flux of low-energy νe, instead of the usual spectral swap

S_3-flavour symmetry as realized in lepton flavour violating processes

A variety of lepton flavour violating effects related to the recent discovery of neutrino oscillations and mixings is here systematically discussed in terms of an S_3-flavour permutational symmetry. After a brief review of some relevant results on lepton masses and mixings, that had been derived in the framework of a Minimal S_3-Invariant Extension of the Standard Model, we derive explicit analytical expressions for the matrices of the Yukawa couplings and compute the branching ratios of some selected flavour changing neutral current (FCNC) processes, as well as, the contribution of the exchange of neutral flavour changing scalars to the anomaly of the muon's magnetic moment as functions of the masses of the charged leptons and the neutral Higgs bosons. We find that the S_3 x Z_2 flavour symmetry and the strong mass hierarchy of the charged leptons strongly suppress the FCNC processes in the leptonic sector well below the present experimental upper bounds by many orders of magnitude. The contribution of FCNC to the anomaly of the muon's magnetic moment is small but non-negligible.Comment: 23 pages, one figure. To appear in J. Phys A: Mathematical and Theoretical (SPE QTS5

Collective neutrino flavor transitions in supernovae and the role of trajectory averaging

Non-linear effects on supernova neutrino oscillations, associated with neutrino self-interactions, are known to induce collective flavor transitions near the supernova core for theta_13 \neq 0. In scenarios with very shallow electron density profiles, these transformations have been shown to couple with ordinary matter effects, jointly producing spectral distortions both in normal and inverted hierarchy. In this work we consider a complementary scenario, characterized by higher electron density, as indicated by post-bounce shock-wave simulations. In this case, early collective flavor transitions are decoupled from later, ordinary matter effects. Moreover, such transitions become more amenable to both numerical computations and analytical interpretations in inverted hierarchy, while they basically vanish in normal hierarchy. We numerically evolve the neutrino density matrix in the region relevant for self-interaction effects. In the approximation of averaged intersection angle between neutrino trajectories, our simulations neatly show the collective phenomena of synchronization, bipolar oscillations, and spectral split, recently discussed in the literature. In the more realistic (but computationally demanding) case of non-averaged neutrino trajectories, our simulations do not show new significant features, apart from the smearing of ``fine structures'' such as bipolar nutations. Our results seem to suggest that, at least for non-shallow matter density profiles, averaging over neutrino trajectories plays a minor role in the final outcome. In this case, the swap of nu_e and nu_{\mu,\tau} spectra above a critical energy may represent an unmistakable signature of the inverted hierarchy, especially for theta_{13} small enough to render further matter effects irrelevant.Comment: v2 (27 pages, including 9 eps figures). Typos removed, references updated. Minor comments added. Corrected numerical errors in Eq.(6). Matches the published versio

Testing matter effects in propagation of atmospheric and long-baseline neutrinos

We quantify our current knowledge of the size and flavor structure of the matter effects in the evolution of atmospheric and long-baseline neutrinos based solely on the analysis of the corresponding neutrino data. To this aim we generalize the matter potential of the Standard Model by rescaling its strength, rotating it away from the e-e sector, and rephasing it with respect to the vacuum term. This phenomenological parametrization can be easily translated in terms of non-standard neutrino interactions in matter. We show that in the most general case, the strength of the potential cannot be determined solely by atmospheric and long-baseline data. However its flavor composition is very much constrained and the present determination of the neutrino masses and mixing is robust under its presence. We also present an update of the constraints arising from this analysis in the particular case in which no potential is present in the e-mu and e-tau sectors. Finally we quantify to what degree in this scenario it is possible to alleviate the tension between the oscillation results for neutrinos and antineutrinos in the MINOS experiment and show the relevance of the high energy part of the spectrum measured at MINOS.Comment: PDFLaTeX file using JHEP3 class, 25 pages, 7 figures included. Accepted for publication in JHE

Non-standard interactions versus non-unitary lepton flavor mixing at a neutrino factory

The impact of heavy mediators on neutrino oscillations is typically described by non-standard four-fermion interactions (NSIs) or non-unitarity (NU). We focus on leptonic dimension-six effective operators which do not produce charged lepton flavor violation. These operators lead to particular correlations among neutrino production, propagation, and detection non-standard effects. We point out that these NSIs and NU phenomenologically lead, in fact, to very similar effects for a neutrino factory, for completely different fundamental reasons. We discuss how the parameters and probabilities are related in this case, and compare the sensitivities. We demonstrate that the NSIs and NU can, in principle, be distinguished for large enough effects at the example of non-standard effects in the $\mu$-$\tau$-sector, which basically corresponds to differentiating between scalars and fermions as heavy mediators as leading order effect. However, we find that a near detector at superbeams could provide very synergistic information, since the correlation between source and matter NSIs is broken for hadronic neutrino production, while NU is a fundamental effect present at any experiment.Comment: 32 pages, 5 figures. Final version published in JHEP. v3: Typo in Eq. (27) correcte

Protein traffic is an intracellular target in alcohol toxicity

Eukaryotic cells comprise a set of organelles, surrounded by membranes with a unique composition, which is maintained by a complex synthesis and transport system. Cells also synthesize the proteins destined for secretion. Together, these processes are known as the secretory pathway or exocytosis. In addition, many molecules can be internalized by cells through a process called endocytosis. Chronic and acute alcohol (ethanol) exposure alters the secretion of different essential products, such as hormones, neurotransmitters and others in a variety of cells, including central nervous system cells. This effect could be due to a range of mechanisms, including alcohol-induced alterations in the different steps involved in intracellular transport, such as glycosylation and vesicular transport along cytoskeleton elements. Moreover, alcohol consumption during pregnancy disrupts developmental processes in the central nervous system. No single mechanism has proved sufficient to account for these effects, and multiple factors are likely involved. One such mechanism indicates that ethanol also perturbs protein trafficking. The purpose of this review is to summarize our understanding of how ethanol exposure alters the trafficking of proteins in different cell systems, especially in central nervous system cells (neurons and astrocytes) in adult and developing brains

Data for: The labor market effects of introducing unemployment benefits in an economy with high informality

Abstract of associated article: Unemployment benefit systems are nonexistent in many developing economies. Introducing such systems poses many challenges which are partly due to the high level of informality in the labor markets of these economies. This paper studies the consequences on the labor market of implementing an unemployment benefit system in economies with large informal sectors and high flows of workers between formality and informality. We build a search and matching model with endogenous destruction, on-the-job search, and intersectoral flows, where agents in the economy decide optimally whether or not to formalize jobs. We calibrate the model for Mexico, and show that the introduction of an unemployment benefit system, where workers contribute when employed in the formal market and collect benefits when they lose their jobs, even if they obtain informal jobs, can lead to an increase in formality in the economy, while also producing small increases in unemployment. The exact impact of incorporating such benefits depends on the relative strength of two opposing effects: the generosity of the benefits and the level of the contributions that finance those benefits. We also show important policy complementarities with other interventions in the labor market. In particular, combining the unemployment benefit program with policies that reduce the cost of formality, such as lower employment taxes and firing costs, can produce greater decreases in informality and lower impacts on unemployment than when the program is applied in isolation