111 research outputs found

    Neutrino Decay and Atmospheric Neutrinos

    Get PDF
    We reconsider neutrino decay as an explanation for atmospheric neutrino observations. We show that if the mass-difference relevant to the two mixed states \nu_\mu and \nu_\tau is very small (< 10^{-4} eV^2), then a very good fit to the observations can be obtained with decay of a component of \nu_\mu to a sterile neutrino and a Majoron. We discuss how the K2K and MINOS long-baseline experiments can distinguish the decay and oscillation scenarios.Comment: 9 pages, Revtex, uses epsf.sty, 3 postscript figures. Additions and corrections to references, minor changes in the text and to some number

    Neutrino Oscillations in the Early Universe with Nonequilibrium Neutrino Distributions

    Get PDF
    Around one second after the big bang, neutrino decoupling and e+e^+-ee^- annihilation distort the Fermi-Dirac spectrum of neutrino energies. Assuming neutrinos have masses and can mix, we compute the distortions using nonequilibrium thermodynamics and the Boltzmann equation. The flavor behavior of neutrinos is studied during and following the generation of the distortion.Comment: accepted for publication in Physical Review

    One pion events by atmospheric neutrinos: A three flavor analysis

    Get PDF
    We study the one-pion events produced via neutral current (NC) and charged current (CC) interactions by the atmospheric neutrinos. We analyze the ratios of these events in the framework of oscillations between three neutrino flavors. The ratios of the CC events induced by νe\nu_e to that of the NC events and a similar ratio defined with νμ\nu_\mu help us in distinguishing the different regions of the neutrino parameter space.Comment: 14 pages, 4 figures (separate postscript files

    T-violation tests for relativity principles

    Get PDF
    We consider the implications of a violation of the equivalence principle or of Lorentz invariance in the neutrino sector for the T-asymmetry ΔPTP(νανβ)P(νβνα)\Delta P_T \equiv P(\nu_{\alpha} \to \nu_{\beta}) - P(\nu_{\beta} \to \nu_{\alpha}) in a three-flavour framework. We find that additional mixing due to these mechanisms, while obeying all present bounds, can lead to a substantial enhancement, suppression, and/or sign change in ΔPT\Delta P_T for the preferred energies and baselines of a neutrino factory. This in turn allows for the possibility of improving existing constraints by several orders of magnitude.Comment: 2 pages; Talk given at the 4th NuFact '02 Workshop (Neutrino Factories Based On Muon Storage Rings), 1-6 Jul 2002, London, England; To appear in proceeding

    On the interactions of melatonin/β-cyclodextrin inclusion complex: A novel approach combining efficient semiempirical extended tight-binding (xtb) results with ab initio methods

    Get PDF
    Melatonin (MT) is a molecule of paramount importance in all living organisms, due to its presence in many biological activities, such as circadian (sleep–wake cycle) and seasonal rhythms (reproduction, fattening, molting, etc.). Unfortunately, it suffers from poor solubility and, to be used as a drug, an appropriate transport vehicle has to be developed, in order to optimize its release in the human tissues. As a possible drug-delivery system, β-cyclodextrin (βCD) represents a promising scaffold which can encapsulate the melatonin, releasing when needed. In this work, we present a computational study supported by experimental IR spectra on inclusion MT/βCD complexes. The aim is to provide a robust, accurate and, at the same time, low-cost methodology to investigate these inclusion complexes both with static and dynamic simulations, in order to study the main actors that drive the interactions of melatonin with β-cyclodextrin and, therefore, to understand its release mechanism

    On the interactions of melatonin/β-cyclodextrin inclusion complex: A novel approach combining efficient semiempirical extended tight-binding (xtb) results with ab initio methods

    Get PDF
    Melatonin (MT) is a molecule of paramount importance in all living organisms, due to its presence in many biological activities, such as circadian (sleep–wake cycle) and seasonal rhythms (reproduction, fattening, molting, etc.). Unfortunately, it suffers from poor solubility and, to be used as a drug, an appropriate transport vehicle has to be developed, in order to optimize its release in the human tissues. As a possible drug-delivery system, β-cyclodextrin (βCD) represents a promising scaffold which can encapsulate the melatonin, releasing when needed. In this work, we present a computational study supported by experimental IR spectra on inclusion MT/βCD complexes. The aim is to provide a robust, accurate and, at the same time, low-cost methodology to investigate these inclusion complexes both with static and dynamic simulations, in order to study the main actors that drive the interactions of melatonin with β-cyclodextrin and, therefore, to understand its release mechanism

    Neuroprotective role of phosphoserine in primary open-angle glaucoma patients

    Get PDF
    OBJECTIVE: To evaluate the neuroprotective role of phosphoserine (P-Ser) in primary open-angle glaucoma (POAG) patients and to compare its therapeutic effectiveness to placebo treatment. PATIENTS AND METHODS: Fifty-one patients (24 males and 27 females) between 35 and 61 years (average 46 years ± 3.8 SD) affected by POAG were enrolled in this study. Patients were divided in two groups: group A included 28 subjects that received an oral P-Ser treatment for 12 months; and group B included 23 subjects that received an oral placebo treatment for 12 months. Complete ophthalmological examination, standard automated perimetric examination, analysis of ON fibers via scanning laser polarimetry and glaucoma staging was performed in all patients at enrolment and 1, 3, 6, and 12 months after. Statistical analysis was performed using STATA 14.0 (Collage Station, TX, USA). RESULTS: Mean deviation (MD) and pattern standard deviation (PSD) analysis by means of 30-2 full threshold of the visual fields (VFs), retinal nerve fiber layer (RNFL) thickness by means of GDx, and IOP were considered to evaluate P-Ser therapy effectiveness in both groups. A statistically significant improvement (p&lt;0.05) in VF, RNFL thickness and IOP compared to pre-treatment was found in patients in group A. CONCLUSIONS: Our study shows a significant improvement in several variables in patients with glaucoma treated with P-Ser compared to placebo and suggests a potential neuroprotective effect of P-Ser in treating glaucoma patients in association with the traditional hypotonic topical therapy

    Accelerator and Reactor Neutrino Oscillation Experiments in a Simple Three-Generation Framework

    Get PDF
    We present a new approach to the analysis of neutrino oscillation experiments, in the one mass-scale limit of the three-generation scheme. In this framework we reanalyze and recombine the most constraining accelerator and reactor data, in order to draw precise bounds in the new parameter space. We consider our graphical representations as particularly suited to show the interplay among the different oscillation channels. Within the same framework, the discovery potential of future short and long baseline experiments is also investigated, in the light of both the recent signal from the LSND experiment and the atmospheric neutrino anomaly.Comment: uuencoded compressed tar file. Figures (13) available by ftp to ftp://eku.sns.ias.edu/pub/lisi/ (192.16.204.30). Submitted to Physical Review

    Fine structure splittings of excited P and D states in charmonium

    Get PDF
    It is shown that the fine structure splittings of the 23PJ2 ^3P_J and 33PJ3 ^3P_J excited states in charmonium are as large as those of the 13PJ1^3P_J state if the same αs(μ)0.36\alpha_s(\mu)\approx 0.36 is used. The predicted mass M(23P0)=3.84M(2 ^3P_0)=3.84 GeV appears to be 120 MeV lower that the center of gravity of the 23PJ2 ^3P_J multiplet and lies below the DDˉD\bar D^* threshold. Our value of M(23P0)M(2 ^3P_0) is approximately 80 MeV lower than that from the paper by Godfrey and Isgur while the differences in the other masses are \la 20 MeV. Relativistic kinematics plays an important role in our analysis.Comment: 12 page

    More Straightforward Extraction of the Fundamental Lepton Mixing Parameters from Long-Baseline Neutrino Oscillations

    Get PDF
    We point out the simple reversibility between the fundamental neutrino mixing parameters in vacuum and their effective counterparts in matter. The former can therefore be expressed in terms of the latter, allowing more straightforward extraction of the genuine lepton mixing quantities from a variety of long-baseline neutrino oscillation experiments. In addition to the parametrization-independent results, we present the formulas based on the standard parametrization of the lepton flavor mixing matrix and give a typical numerical illustration.Comment: RevTex 10 pages. Minor changes. Phys. Rev. D in printin
    corecore