Implications of a new light gauge boson for neutrino physics

We study the impact of light gauge bosons on neutrino physics. We show that they can explain the NuTeV anomaly and also escape the constraints from neutrino experiments if they are very weakly coupled and have a mass of a few GeV. Lighter gauge bosons with stronger couplings could explain both the NuTeV anomaly and the positive anomalous magnetic moment of the muon. However, in the simple model we consider in this paper (say a purely vectorial extra U(1) current), they appear to be in conflict with the precise measurements of \nu-e elastic scattering cross sections. The surprising agreement that we obtain between our naive model and the NuTeV anomaly for a Z' mass of a few GeV may be a coincidence. However, we think it is interesting enough to deserve attention and perhaps a more careful analysis, especially since a new light gauge boson is a very important ingredient for the Light Dark Matter scenario.Comment: 9 page

On universality of the coupling of neutrinos to Z

We employ an effective Lagrangian approach and use LEP data to place severe bounds on universality violations of the couplings of $\nu_e$, $\nu_\mu$, and $\nu_\tau$ to the $Z$ boson. Our results justify the assumption of universality in these couplings that is usually made, as for example in the analysis of solar neutrinos detected at SNO.Comment: 8 pages, no figures. A few comments added. It matches version to be published in PR

Invisible Z-Boson Decays at e+e- Colliders

The measurement of the invisible Z-boson decay width at e+e- colliders can be done "indirectly", by subtracting the Z-boson visible partial widths from the Z-boson total width, or "directly", from the process e+e- -> \gamma \nu \bar{\nu}. Both procedures are sensitive to different types of new physics and provide information about the couplings of the neutrinos to the Z-boson. At present, measurements at LEP and CHARM II are capable of constraining the left-handed Z\nu\nu-coupling, 0.45 <~ g_L <~ 0.5, while the right-handed one is only mildly bounded, |g_R| <= 0.2. We show that measurements at a future e+e- linear collider at different center-of-mass energies, \sqrt{s} = MZ and \sqrt{s}s ~ 170 GeV, would translate into a markedly more precise measurement of the Z\nu\nu-couplings. A statistically significant deviation from Standard Model predictions will point toward different new physics mechanisms, depending on whether the discrepancy appears in the direct or the indirect measurement of the invisible Z-width. We discuss some scenarios which illustrate the ability of different invisible Z-boson decay measurements to constrain new physics beyond the Standard Model

Le concept de maladies virales émergentes : quel risque de zoonose pour La Réunion ?

A La Réunion, le risque d'émergence de maladies virales est constitué par plusieurs zoonoses virales qu'il convient de surveiller: infections à virus Sindbis, virus de l'encéphalite japonaise, virus Wesselsbron, virus Nipah, virus Zika, virus West Nile, virus de la fièvre de la vallée du Rift. La lutte contre ces maladies virales émergentes (MVE) passe par une détection précoce des cas et donc un système de surveillance doté d'un véritable réseau d'information, d'alerte et de prévention international. (Résumé d'auteur

Glial β-Oxidation regulates drosophila energy metabolism

The brain's impotence to utilize long-chain fatty acids as fuel, one of the dogmas in neuroscience, is surprising, since the nervous system is the tissue most energy consuming and most vulnerable to a lack of energy. Challenging this view, we here show in vivo that loss of the Drosophila carnitine palmitoyltransferase 2 (CPT2), an enzyme required for mitochondrial β-oxidation of long-chain fatty acids as substrates for energy production, results in the accumulation of triacylglyceride-filled lipid droplets in adult Drosophila brain but not in obesity. CPT2 rescue in glial cells alone is sufficient to restore triacylglyceride homeostasis, and we suggest that this is mediated by the release of ketone bodies from the rescued glial cells. These results demonstrate that the adult brain is able to catabolize fatty acids for cellular energy production.This work was partially supported by the Flanders Fund for Scientific Research (FWO G 0.666.10N), NEUROBRAINNET IAP 7/16, Flemish Government Methusalem Grant, Spanish Ministry of Science (SAF2010-14906) and Innovation Ingenio-Consolider (CSD2010-00045) and Spanish Ministry of Economy and Competitiveness (SAF2013-45392).Peer Reviewe

Glial β-Oxidation regulates drosophila energy metabolism

The brain's impotence to utilize long-chain fatty acids as fuel, one of the dogmas in neuroscience, is surprising, since the nervous system is the tissue most energy consuming and most vulnerable to a lack of energy. Challenging this view, we here show in vivo that loss of the Drosophila carnitine palmitoyltransferase 2 (CPT2), an enzyme required for mitochondrial β-oxidation of long-chain fatty acids as substrates for energy production, results in the accumulation of triacylglyceride-filled lipid droplets in adult Drosophila brain but not in obesity. CPT2 rescue in glial cells alone is sufficient to restore triacylglyceride homeostasis, and we suggest that this is mediated by the release of ketone bodies from the rescued glial cells. These results demonstrate that the adult brain is able to catabolize fatty acids for cellular energy production.This work was partially supported by the Flanders Fund for Scientific Research (FWO G 0.666.10N), NEUROBRAINNET IAP 7/16, Flemish Government Methusalem Grant, Spanish Ministry of Science (SAF2010-14906) and Innovation Ingenio-Consolider (CSD2010-00045) and Spanish Ministry of Economy and Competitiveness (SAF2013-45392).Peer Reviewe

A Search for leptophilic Z_(l) boson at future linear colliders

We study the possible dynamics associated with leptonic charge in future linear colliders. Leptophilic massive vector boson, Z_(l), have been investigated through the process e^(+)e^(-) -> mu^(+)mu^(-). We have shown that ILC and CLIC will give opportunity to observe Z_(l) with masses up to the center of mass energy if the corresponding coupling constant g_(l) exceeds 10^(-3).Comment: 12 pages, 10 figure

Semileptonic decays of light quarks beyond the Standard Model

We describe non-standard contributions to semileptonic processes in a model independent way in terms of an SU(2)_L X U(1)_Y invariant effective lagrangian at the weak scale, from which we derive the low-energy effective lagrangian governing muon and beta decays. We find that the deviation from Cabibbo universality, \Delta_CKM = |V_ud|^2 + |V_us|^2 + |V_ub|^2 - 1, receives contributions from four effective operators. The phenomenological bound of \Delta_CKM = -1E-4 +- 6E-4 provides strong constraints on all four operators, corresponding to an effective scale greater than 11 TeV (90% CL). Depending on the operator, this constraint is at the same level or better then the Z pole observables. Conversely, precision electroweak constraints alone would allow universality violations as large as \Delta_CKM = -0.01 (90% CL). An observed nonzero \Delta_CKM at this level could be explained in terms of a single four-fermion operator which is relatively poorly constrained by electroweak precision measurements.Comment: 23 pages, 1 table and 5 eps figure