1,750 research outputs found

    Detecting atmospheric neutrino oscillations in the ATLAS detector at CERN

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    We discuss the possibility to study oscillations of atmospheric neutrinos in the ATLAS experiment at CERN. Due to the large total detector mass, a significant number of events is expected, and during the shutdown phases of the LHC, reconstruction of these events will be possible with very good energy and angular resolutions, and with charge identification. We argue that 500 live days of neutrino running could be achieved, and that a total of ~160 contained \nu_\mu events and ~360 upward going muons could be collected during this time. Despite the low statistics, the excellent detector resolution will allow for an unambiguous confirmation of atmospheric neutrino oscillations and for measurements of the leading oscillation parameters. Though our detailed simulations show that the sensitivity of ATLAS is worse than that of dedicated neutrino experiments, we demonstrate that more sophisticated detectors, e.g. at the ILC, could be highly competitive with upcoming superbeam experiments, and might even give indications for the mass hierarchy and for the value of theta-13.Comment: 8 pages, 4 figures, 2 tables, RevTeX 4; modified treatment of upward going muons, results unchanged; matches published versio

    Neutrino oscillation probabilities: Sensitivity to parameters

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    We study in detail the sensitivity of neutrino oscillation probabilities to the fundamental neutrino parameters and their possible determination through experiments. The first part of the paper is devoted to the broad theme of isolating regions in the neutrino (and anti-neutrino) energy and propagation length that are sensitive to the oscillation parameters. Such a study is relevant to neutrinos both from the Earth's atmosphere or from a neutrino factory. For completeness we discuss the sensitivity, however small, to the parameters involved in a three-generation framework, and to the Earth matter density profile. We then study processes relevant to atmospheric neutrinos which are sensitive to and allow precision measurements of the mixing angle theta_23 and mass-squared difference delta_32 apart from the mixing angle theta_13. Crucial to this analysis is charge identification; detectors having this capability can isolate these matter effects. In particular, we address the issue of using matter effects to determine whether the mixing angle theta_23 is maximal, and, if not, to explore how well its octant can be determined. When realistic detector resolutions are included, we find that deviations of about 15% (20%) from a maximal value of sin^2 theta_23=1/2 can be measured at 95% (99%) CL provided theta_13 is non-zero, sin^2 theta_13 >= 0.015, and the neutrino mass ordering is normal, with fairly large exposures of 1000 kton-years.Comment: 37 pages Latex file, 30 eps figure files; minor typos fixe

    Neutrinos from Stellar Collapse: Comparison of signatures in water and heavy water detectors

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    Signatures of neutrino and antineutrino signals from stellar collapse in heavy water detectors are contrasted with those in water detectors. The effects of mixing, especially due to the highly dense matter in the supernova core, are studied. The mixing parameters used are those sets allowed by current understanding of available neutrino data: from solar, atmospheric and laboratory neutrino experiments. Signals at a heavy water detector, especially the dominant charged current reactions on deuteron, are very sensitive to some of these sets of allowed mixing parameters. Theoretical uncertainties on supernova neutrino spectra notwithstanding, a combination of supernova measurements with water and heavy water detectors may be able to distinguish many of these mixing possibilities and thus help in ruling out many of them.Comment: 36 pages Latex file, with 13 postscript figures; important improvements in the analysis and more detailed presentation of results. To appear in Phys. Rev.

    A PILOT STUDY ON MANAGEMENT OF MADHUMEGAM (DIABETES MELLITUS TYPE-II) AT NATIONAL INSTITUTE OF SIDDHA, CHENNAI-47.

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        To rule out which of the combination of drug is the most beneficial for the patient to manage Madhumegam(Diabetes-Type-2). Some of them are taking only siddha medicines, and some of them are taking siddha medicines combined with allopathic medicines. So we have planned to do a pilot study on the management of Madhumegam patients in NIS as a Retrospective study.Data collection for assessment has been done by retrieving from the individuals' OPD records and using questionnaire method, at the time of OPD treatment at NIS. Data for 105 Madhumegam patients were collected  and taken up for the study.The statistical analysis reveals that the reduction of blood sugar for(siddha only) Group I at fasting was statistically significant(P<0.0001) and Group-II(siddha and allopathy) it was not significant(P=0.73).  The statistical analysis reveals that the reduction of blood sugar for(siddha only) Group I at postprandial was statistically significant(P<0.0001) and Group-II(siddha and allopathy) it was not significant(P=0.55). The stability of sugar level is seen in siddha group, but a marked deviation is in the combined group. The siddha medicine alone treated group (Group I) shows significant reduction of blood sugar both at fasting and post prandial. The siddha and allopathy treated group(Group II) has not shown significant reduction.Key words: Madhumegam, siddha,diabetes,allopathy, Retrospective, blood sugar

    Threshold Effects on Quasi-degenerate Neutrinos with High-scale Mixing Unification

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    We consider threshold effects on neutrino masses and mixings in a recently proposed model for understanding large solar and atmospheric mixing angles using radiative magnification for the case of quasi-degenerate neutrinos. We show that the magnitude of the threshold effects is sufficient to bring concordance between the predictions of this model and latest data from KamLAND{\rm KamLAND} and SNO{\rm SNO} on observations of neutrino oscillations.Comment: Four pages, no figure

    Double Threefold Degeneracies for Active and Sterile Neutrinos

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    We explore the possibility that the 3 active (doublet) neutrinos have nearly degenerate masses which are split only by the usual seesaw mechanism from 3 sterile (singlet) neutrinos in the presence of a softly broken A4A_4 symmetry. We take the unconventional view that the sterile neutrinos may be light, i.e. less than 1 keV, and discuss some very interesting and novel phenomenology, including a connection between the LSND neutrino data and solar neutrino oscillations.Comment: 8 pages, no figur

    Somatic embryo formation by cultured ovules of Cabernet Sauvignon grape: Effects of fertilization and of the male gameticide toluidine blue

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    Maximum numbers of pollen tubes were found in styles of plants growing at 27 °C (day) and 22 °C (night). Fertilization generally occurred by 24 h after anthesis. Treatment of both isolated pollen and inflorescences of intact vines with toluidine blue (10-100mg l-1) reduced pollen germination and tube growth. Pollen tubes which penetrated the styles of toluidine blue-treated flowers appeared to be abnormal. Somatic embryos were produced with equal frequency by nucellus tissue from cultured ovules from both normally-fertilized and toluidine blue-treated flowers. There was degeneration of embryosacs in all cultured ovules. The grape appears to be unresponsive to toluidine blue as an inducer of haploid parthenogenesis
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