8,033 research outputs found

    Spectroscopic Identification of the Infrared Counterpart to GX5-1

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    Using CGS4 on UKIRT, we have obtained a 1.95-2.45 micron infrared spectrum of the primary candidate counterpart to the bright Z LMXB GX5-1. IR photometry by Naylor, Charles, & Longmore (1992) and the astrometry of Jonker et al. (2000) had previously identified this star as the most likely counterpart to GX5-1. The spectrum presented here clearly shows Brackett gamma and He lines in emission, for the first time confirming the identity of the counterpart. Similar to our previous spectroscopy of the Z source LMXBs Sco X-1 and Sco X-2 (Bandyopadhyay et al. 1999), the K-band spectrum of GX5-1 shows emission lines only. We briefly discuss the implications of this spectrum for the nature of the Z sources.Comment: accepted for publication as a Letter in MNRA

    Displaced Higgs production in type III seesaw

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    We point out that the type III seesaw mechanism introducing fermion triplets predicts peculiar Higgs boson signatures of displaced vertices with two b jets and one or two charged particles which can be cleanly identified. In a supersymmetric theory, the scalar partner of the fermion triplet contains a neutral dark matter candidate which is almost degenerate with its charged components. A Higgs boson can be produced together with such a dark matter triplet in the cascade decay chain of a strongly produced squark or gluino. When the next lightest supersymmetric particle (NLSP) is bino/wino-like, there appears a Higgs boson associated with two charged tracks of a charged lepton and a heavy charged scalar at a displacement larger than about 1 mm. The corresponding production cross-section is about 0.5 fb for the squark/gluino mass of 1 TeV. In the case of the stau NLSP, it decays mainly to a Higgs boson and a heavy charged scalar whose decay length is larger than 0.1 mm for the stau NLSP mixing with the left-handed stau smaller than 0.3. As this process can have a large cascade production 2\sim 2 pb for the squark/gluino mass 1\sim 1 TeV, one may be able to probe it at the early stage of the LHC experiment.Comment: 10 pages, 5 figure

    Optimal Universal Disentangling Machine for Two Qubit Quantum States

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    We derive the optimal curve satisfied by the reduction factors, in the case of universal disentangling machine which uses only local operations. Impossibility of constructing a better disentangling machine, by using non-local operations, is discussed.Comment: 15 pages, 2 eps figures, 1 section added, 1 eps figure added, minor corrections, 2 reference numbers correcte

    Aflatoxin control projects launched in southern Africa

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    Aflatoxins, produced by the fungus Aspergillus flavus, are a major health concern because of their acute and chronic health effects on humans and domesticated animals. The Centers for Disease Control (CDC) estimates that more than 4.5 billion people in the developing world are chronically exposed to aflatoxins through diet. High doses cause serious illness like acute liver cirrhosis and death. Chronic exposure is widespread, leading to nutritional and immunological effects, and cancer. For example, two independent studies have linked aflatoxin to immune suppression, increased susceptibility to diseases (e.g. HIV and malaria), and possible compromised vaccine efficacy. Of particular concern is aflatoxin’s role in reduction of child growth and development. Since chronic diseases in developing countries are underreported, acute aflatoxicosis outbreaks, like the ones recently documented in Kenya with over 100s of deaths, are likely to be an underestimation of the true size of the problem

    The AgResults Nigeria Aflasafe TM Challenge Project: 2019 Annual Report

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    This report documents the key activities that were carried under the AgResults Aflasafe Pilot Project during the 2018/ 2019 maize-growing season on the verification process to trigger premium payments for successfully harvested and aggregated Aflasafe™-treated maize

    Infrared Photometric Variability of GX13+1 and GX17+2

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    We present infrared photometry of the Galactic Bulge X-ray binary systems GX13+1 and GX17+2 obtained in 1997 July and August using OSIRIS on the 1.8m Perkins Telescope at Lowell Observatory. GX13+1 clearly varies over ~0.6 magnitudes in the K-band. Our light curve suggests a modulation on a timescale of ~20 days, which is in agreement with previously proposed orbital periods for the system. The IR counterpart of GX17+2 is also variable in the K-band over \~0.8 magnitudes on a timescale of days to weeks, extending the variability first seen by Naylor, Charles, & Longmore (1991). We discuss the implications our data have for Deutsch et al's (1999) identification of ``star A'' as the true IR counterpart of GX17+2. The variability observed in our photometry of the blend of star A and the foreground star NP Ser implies a ~4 magnitude intrinsic variation in the K-band for GX17+2.Comment: Accepted for publication in ApJ, 5 pages, 4 figure

    Precision measurement of solar neutrino oscillation parameters by a long-baseline reactor neutrino experiment in Europe

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    We consider the determination of the solar neutrino oscillation parameters Δm212\Delta m^2_{21} and θ12\theta_{12} by studying oscillations of reactor anti-neutrinos emitted by nuclear power plants (located mainly in France) with a detector installed in the Frejus underground laboratory. The performances of a water Cerenkov detector of 147 kt fiducial mass doped with 0.1% of Gadolinium (MEMPHYS-Gd) and of a 50 kt scale liquid scintillator detector (LENA) are compared. In both cases 3σ\sigma uncertainties below 3% on Δm212\Delta m^2_{21} and of about 20% on sin2θ12\sin^2\theta_{12} can be obtained after one year of data taking. The Gadolinium doped Super-Kamiokande detector (SK-Gd) in Japan can reach a similar precision if the SK/MEMPHYS fiducial mass ratio of 1 to 7 is compensated by a longer SK-Gd data taking time. Several years of reactor neutrino data collected by MEMPHYS-Gd or LENA would allow a determination of Δm212\Delta m^2_{21} and sin2θ12\sin^2\theta_{12} with uncertainties of approximately 1% and 10% at 3σ\sigma, respectively. These accuracies are comparable to those that can be reached in the measurement of the atmospheric neutrino oscillation parameters Δm312\Delta m^2_{31} and sin2θ23\sin^2\theta_{23} in long-baseline superbeam experiments.Comment: 16 pages, 6 figure

    Solar Model Parameters and Direct Measurements of Solar Neutrino Fluxes

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    We explore a novel possibility of determining the solar model parameters, which serve as input in the calculations of the solar neutrino fluxes, by exploiting the data from direct measurements of the fluxes. More specifically, we use the rather precise value of the 8B^8B neutrino flux, ϕB\phi_B obtained from the global analysis of the solar neutrino and KamLAND data, to derive constraints on each of the solar model parameters on which ϕB\phi_B depends. We also use more precise values of 7Be^7Be and pppp fluxes as can be obtained from future prospective data and discuss whether such measurements can help in reducing the uncertainties of one or more input parameters of the Standard Solar Model.Comment: 25 pages, 3 figure
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