6,766 research outputs found

    νμ\nu_\mu disappearance at the SPL, T2K-I and the Neutrino Factory

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    We study the νμ\nu_\mu disappearance channel at T2K-phase I and the SPL and analyse the achievable reduction of present uncertainties in θ23\theta_{23} and Δm232\Delta m^2_{23}. We analyse the impact of discrete ambiguities in sign(Δm223\Delta m^2{23}) and sign(2tanθ232 \tan \theta_{23}). We show how the disappearance channel at the Neutrino Factory is complementary to the ``golden'' and ``silver'' appearance channels and can be used to reduce the eightfold-ambiguity problem in (θ13δ\theta_{13}-\delta).Comment: 2 pages, 3 epsfig; NUFACT'05, 21-26 June 2005, Frascat

    Micro-orbits in a many-branes model and deviations from 1/r21/r^2 Newton's law

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    We consider a 5-dimensional model with geometry M=M4×S1{\cal M} = {\cal M}_4 \times {\cal S}_1, with compactification radius RR. The Standard Model particles are localized onto a brane located at y=0, with identical branes localized at different points in the extra dimension. Objects located on our brane can orbit around objects located on a brane at a distance d=y/Rd=y/R, with an orbit and a period significantly different from the standard Newtonian ones. We study the kinematical properties of the orbits, finding that it is possible to distinguish one motion from the other in a large region of the initial conditions parameter space. This is a warm-up to study if a SM-like mass distribution on one (or more) distant brane(s) may represent a possible dark matter candidate. After using the same technique to the study of orbits of objects lying on the same brane (d=0d=0), we apply this method to detect generic deviations from the inverse-square Newton's law. We propose a possible experimental setup to look for departures from Newtonian motion in the micro-world, finding that an order of magnitude improvement on present bounds can be attained at the 95% CL under reasonable assumptions.Comment: Two-column format (20 pages), 10 figures; minor corrections and some added reference

    Full QCD on APE100 Machines

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    We present the first tests and results from a study of QCD with two flavours of dynamical Wilson fermions using the Hybrid Monte Carlo Algorithm (HMCA) on APE100 machines.Comment: 23 pages, LaTeX, 13 PS figures not include

    Physics reach of β\beta-beams and ν\nu-factories: the problem of degeneracies

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    We discuss the physics reach of β\beta-Beams and ν\nu-Factories from a theoretical perspective, having as a guideline the problem of degeneracies. The presence of degenerate solutions in the measure of the neutrino oscillation parameters θ13\theta_{13} and δ\delta is, in fact, the main problem that have to be addressed in planning future neutrino oscillation experiments. If degeneracies are not (at least partially) solved, it will be almost impossible to perform, at any future facility, precise measurements of θ13\theta_{13} and/or δ\delta. After a pedagogical introduction on why degenerate solutions arise and how we can get rid of them, we analyze the physics reach of current β\beta-beam and ν\nu-factory configurations. The physics reach of the "standard" \BB is severely affected by degeneracies while a better result can be obtained by higher-γ\gamma setups. At the \NF the combination of Golden and Silver channels can solve the eightfold degeneracy down to sin2θ13103\sin^2\theta_{13} \le 10^{-3}Comment: 5 pages, 6 epsfig; NUFACT'05, 21-26 June 2005, Frascat

    Invisible Z decay width bounds on active-sterile neutrino mixing in the (3+1) and (3+2) models

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    In this work we consider the standard model extended with singlet sterile neutrinos with mass in the eV range and mixed with the active neutrinos. The active-sterile neutrino mixing renders new contributions to the invisible Z decay width which, in the case of light sterile neutrinos, depends on the active-sterile mixing matrix elements only. We then use the current experimental value of the invisible Z decay width to obtain bounds on these mixing matrix elements for both (3+1) and (3+2) models.Comment: 10 pages, 5 figure

    νμ\nu_\mu disappearance at the SPL, T2K-I, NOν\nuA and the Neutrino Factory

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    We study the measurement of the atmospheric neutrino oscillation parameters, θ23\theta_{23} and Δm232\Delta m^2_{23}, at the νμ\nu_\mu disappearance channel at three conventional beam facilities, the SPL, T2K-phase I and NOν\nuA. These two parameters have been shown to be of crucial importance in the measurement of two of the unknowns of the PMNS mixing matrix, θ13\theta_{13} and the leptonic CP-violating phase δ\delta. In our analyis, the effect of the two discrete ambiguities, sign(Δm232){\rm sign}(\Delta m^2_{23}) and sign(tan2θ23){\rm sign}(\tan 2 \theta_{23}), is explicitly taken into account. We analyse also the νμ\nu_\mu disappearance channel at the Neutrino Factory, and combine it with the ``golden'' νeνμ\nu_e \to \nu_\mu and ``silver'' νeντ\nu_e \to \nu_\tau appearance channels to study its impact on the measurement of θ13\theta_{13} and δ\delta. Eventually, we present the sensitivity of the four facilities to different observables: θ13\theta_{13}, δ\delta, maximal θ23\theta_{23}, the sign of the atmospheric mass difference, satms_{atm}, and the θ23\theta_{23}-octant, socts_{oct}.Comment: 40 pages using epsfig; bibliography modifie

    Degeneracies at a beta-Beam and a Super-Beam Facility

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    The presence of degeneracies can considerably worsen the measure of the neutrino oscillation parameters θ13\theta_{13} and δ\delta. We study the physics reach of a specific ``CERN'' setup, using a standard β\beta-Beam and Super-Beam facility. These facilities have a similar sensitivity in both parameters. Their combination does not provide any dramatic improvement as expected due to their almost identical L/E ratio. We analyse if adding the correspondent disappearance channels can help in reducing the effect of degeneracies in the (θ13,δ)(\theta_{13},\delta) measure.Comment: 5 pages, 7 eps figure

    Clone flow analysis for a theory inspired Neutrino Experiment planning

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    The presence of several clone solutions in the simultaneous measurement of (θ13,δ\theta_{13},\delta) has been widely discussed in literature. In this letter we write the analytical formulae of the clones location in the (θ13,δ\theta_{13},\delta) plane as a function of the physical input pair (θˉ13,δˉ\bar\theta_{13},\bar\delta). We show how the clones move with changing θˉ13\bar\theta_{13}. The "clone flow" can be significantly different if computed (naively) from the oscillation probabilities or (exactly) from the probabilities integrated over the neutrino flux and cross-section. Using our complete computation we compare the clone flow of a set of possible future neutrino experiments: the CERN SuperBeam, BetaBeam and Neutrino Factory proposals. We show that the combination of these specific BetaBeam and SuperBeam does not help in solving the degeneracies. On the contrary, the combination of one of them with the Neutrino Factory Golden and Silver channel can be used, from a theoretical point of view, to solve completely the eightfold degeneracy.Comment: 23 pages, using epsfi

    Circulating SIRT1 inversely correlates with epicardial fat thickness in patients with obesity

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    Background and aim: Obesity is increasing worldwide and is related to undesirable cardiovascular outcomes. Epicardial fat (EF), the heart visceral fat depot, increases with obesity and correlates with cardiovascular risk. SIRT1, an enzyme regulating metabolic circuits linked with obesity, has a cardioprotective effect and is a predictor of cardiovascular events. We aimed to assess the relationship of EF thickness (EFT) with circulating SIRT1 in patients with obesity. Methods and results: Sixty-two patients affected by obesity and 23 lean controls were studied. Plasma SIRT1 concentration was determined by enzyme-linked immunosorbent assay (ELISA). EFT was measured by echocardiography. Body mass index (BMI), waist circumference, heart rate (HR), blood pressure, and laboratory findings (fasting glucose, insulin, HbA1c, cholesterol, and triglycerides) were assessed. SIRT1 was significantly lower (P = 0.002) and EFT was higher (P < 0.0001) in patients with obesity compared with lean controls. SIRT1 showed a negative correlation with EFT and HR in the obesity group (rho = -0.350, P = 0.005; rho = -0.303, P = 0.008, respectively). After adjustment for obesity-correlated variables, multiple linear regression analysis showed that EFT remained the best correlate of SIRT1 (beta = -0.352, P = 0.016). Conclusions: Circulating SIRT1 correlates with the visceral fat content of the heart. Serum SIRT1 levels might provide additional information for risk assessment of coronary artery disease in patients with obesity. (C) 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved

    Sterile neutrinos in neutrinoless double beta decay

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    We study possible contribution of the Majorana neutrino mass eigenstate νh\nu_h dominated by a sterile neutrino component to neutrinoless double beta (0νββ0\nu\beta\beta) decay. From the current experimental lower bound on the 0νββ0\nu\beta\beta-decay half-life of 76^{76}Ge we derive stringent constraints on the νhνe\nu_h-\nu_e mixing in a wide region of the values of νh\nu_h mass. We discuss cosmological and astrophysical status of νh\nu_h in this mass region.Comment: 6 pages, 1 figure; v2 added comments and reference
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