759 research outputs found

    Off-limb (spicule) DEM distribution from SoHO/SUMER observations

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    In the present work we derive a Differential Emission Measure (DEM) dis- tribution from a region dominated by spicules. We use spectral data from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on-board the Solar Heliospheric Observatory (SoHO) covering the entire SUMER wavelength range taken off-limb in the Northern polar coronal hole to construct this DEM distribution using the CHIANTI atomic database. This distribution is then used to study the thermal properties of the emission contributing to the 171 {\AA} channel in the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO). From our off-limb DEM we found that the radiance in the AIA 171 {\AA} channel is dominated by emission from the Fe ix 171.07 {\AA} line and has sparingly little contribution from other lines. The product of the Fe ix 171.07 {\AA} line contribution function with the off-limb DEM was found to have a maximum at logTmax (K) = 5.8 indicating that during spicule observations the emission in this line comes from plasma at transition region temperatures rather than coronal. For comparison, the same product with a quiet Sun and prominence DEM were found to have a maximum at logT max (K) = 5.9 and logTmax (K) = 5.7, respectively. We point out that the interpretation of data obtained from the AIA 171 {\AA} filter should be done with foreknowledge of the thermal nature of the observed phenomenon. For example, with an off-limb DEM we find that only 3.6% of the plasma is above a million degrees, whereas using a quiet Sun DEM, this contribution rises to 15%.Comment: 12 pages, 6 figures accepted by Solar Physic

    TeV-scale seesaw from a multi-Higgs model

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    We suggest new simple model of generating tiny neutrino masses through a TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model is a simple extension of the standard model by introducing extra one Higgs singlet, and one Higgs doublet with a tiny vacuum expectation value. Experimental constraints, electroweak precision data and no large flavor changing neutral currents, are satisfied since the extra doublet only has a Yukawa interaction with lepton doublets and right-handed neutrinos, and their masses are heavy of order a TeV-scale. Since active light neutrinos are Majorana particles, this model predicts a neutrinoless double beta decay.Comment: 21 pages, 8 figure

    Lepton flavor violating signals of a little Higgs model at the high energy linear e+ee^{+}e^{-} colliders

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    Littlest Higgs (LH)(LH) model predicts the existence of the doubly charged scalars Φ±±\Phi^{\pm\pm}, which generally have large flavor changing couplings to leptons. We calculate the contributions of Φ±±\Phi^{\pm\pm} to the lepton flavor violating (LFV)(LFV) processes liljγl_{i}\to l_{j}\gamma and liljlklkl_{i}\to l_{j}l_{k}l_{k}, and compare our numerical results with the current experimental upper limits on these processes. We find that some of these processes can give severe constraints on the coupling constant YijY_{ij} and the mass parameter MΦM_{\Phi}. Taking into account the constraints on these free parameters, we further discuss the possible lepton flavor violating signals of Φ±±\Phi^{\pm\pm} at the high energy linear e+ee^{+}e^{-} collider (ILC)(ILC) experiments. Our numerical results show that the possible signals of Φ±±\Phi^{\pm\pm} might be detected via the subprocesses e±e±l±l±e^{\pm}e^{\pm}\to l^{\pm}l^{\pm} in the future ILCILC experiments.Comment: 16 pages, 7 figures. Discussions and references added, typos correcte

    Mapping net blotch resistance in ‘Nomini’ and CIho 2291 barley

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    Net blotch (Pyrenophora teres) is one of the most devastating diseases of barley (Hordeum vulgare L.) worldwide. Identification of diagnostic molecular markers associated with genes and quantitative trait loci (QTL) for net blotch resistance will facilitate pyramiding of independent genes. Linkage mapping was used to identify chromosomal locations of the independent, dominant genes conditioning net blotch resistance in the winter barley ‘Nomini’ (PI 566929) and spring barley CIho 2291. The F2 populations of 238 and 193 individuals, derived from crosses between the susceptible spring barley parent ‘Hector’ (CIho 15514) and the resistant parents Nomini and CIho 2291, respectively, were used to map the genes governing resistance in the resistant parents. The dominant gene governing resistance in Nomini, temporarily designated Rpt-Nomini, was mapped to a 9.2-cM region of barley chromosome 6H between the flanking microsatellite markers Bmag0344a (r2 = 0.7) and Bmag0103a (r2 = 0.9), which were 6.8 and 2.4 cM away from Rpt-Nomini, respectively. The dominant gene governing resistance in CIho 2291, temporarily designated Rpt-CIho2291, was mapped to a 34.3-cM interval on the distal region of barley chromosome 6H between the flanking microsatellite markers Bmag0173 (r2 = 0.65) and Bmag0500 (r2 = 0.26), which were 9.9 and 24.4 cM away from Rpt-CIho2291, respectively. Identification of the chromosomal location of Rpt-Nomini and Rpt-CIho2291 will facilitate efforts in pyramiding multiple genes for net blotch resistance

    The HO Southern Galactic Plane Survey (HOPS) - I. Techniques and HO maser data

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    The definitive version can be found at: http://onlinelibrary.wiley.com/ Copyright Royal Astronomical SocietyWe present first results of the HO Southern Galactic Plane Survey (HOPS), using the Mopra Radio Telescope with a broad-band backend and a beam size of about 2 arcmin. We have observed 100 deg of the southern Galactic plane at 12mm (19.5-27.5GHz), including spectral line emission from HO masers, multiple metastable transitions of ammonia, cyanoacetylene, methanol and radio recombination lines. In this paper, we report on the characteristics of the survey and HO maser emission. We find 540 HO masers, of which 334 are new detections. The strongest maser is 3933Jy and the weakest is 0.7Jy, with 62 masers over 100Jy. In 14 maser sites, the spread in the velocity of the HO maser emission exceeds 100kms. In one region, the HO maser velocities are separated by 351.3kms. The rms noise levels are typically between 1 and 2Jy, with 95 per cent of the survey under 2Jy. We estimate completeness limits of 98 per cent at around 8.4Jy and 50 per cent at around 5.5Jy. We estimate that there are between 800 and 1500 HO masers in the Galaxy that are detectable in a survey with similar completeness limits to HOPS. We report possible masers in NH (11,9) and (8,6) emission towards G19.61-0.23 and in the NH (3,3) line towards G23.33-0.30.Peer reviewe

    Lepton Flavor Violating Process in Bi-maximal texture of Neutrino Mixings

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    We investigate the lepton flavor violation in the framework of the MSSM with right-handed neutrinos taking the large mixing angle MSW solution in the quasi-degenerate and the inverse-hierarchical neutrino masses. We predict the branching ratio of μe+γ\mu \to e+\gamma and τμ+γ\tau \to \mu+\gamma processes assuming the degenerate right-handed Majorana neutrino masses. We find that the branching ratio in the quasi-degenerate neutrino mass spectrum is 100 times smaller than the ones in the inverse-hierarchical and the hierarchical neutrino spectra. We emphasize that the magnitude of Ue3U_{e3} is one of important ingredients to predict BR(μe+γ\mu \to e +\gamma ). The effect of the deviation from the complete-degenerate right-handed Majorana neutrino masses are also estimated. Furtheremore, we examine the S_{3\sL}\times S_{3\sR} model, which gives the quasi-degenerate neutrino masses, and the Shafi-Tavartkiladze model, which gives the inverse-hierarchical neutrino masses. Both predicted branching ratios of μe+γ\mu\to e+\gamma are smaller than the experimantal bound.Comment: Latex file, 38 pages, 10 figures, revised versio

    Pion emission from the T2K replica target: method, results and application

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    The T2K long-baseline neutrino oscillation experiment in Japan needs precise predictions of the initial neutrino flux. The highest precision can be reached based on detailed measurements of hadron emission from the same target as used by T2K exposed to a proton beam of the same kinetic energy of 30 GeV. The corresponding data were recorded in 2007-2010 by the NA61/SHINE experiment at the CERN SPS using a replica of the T2K graphite target. In this paper details of the experiment, data taking, data analysis method and results from the 2007 pilot run are presented. Furthermore, the application of the NA61/SHINE measurements to the predictions of the T2K initial neutrino flux is described and discussed.Comment: updated version as published by NIM

    Exploring flavor structure of supersymmetry breaking from rare B decays and unitarity triangle

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    We study effects of supersymmetric particles in various rare B decay processes as well as in the unitarity triangle analysis. We consider three different supersymmetric models, the minimal supergravity, SU(5) SUSY GUT with right-handed neutrinos, and the minimal supersymmetric standard model with U(2) flavor symmetry. In the SU(5) SUSY GUT with right-handed neutrinos, we consider two cases of the mass matrix of the right-handed neutrinos. We calculate direct and mixing-induced CP asymmetries in the b to s gamma decay and CP asymmetry in B_d to phi K_S as well as the B_s--anti-B_s mixing amplitude for the unitarity triangle analysis in these models. We show that large deviations are possible for the SU(5) SUSY GUT and the U(2) model. The pattern and correlations of deviations from the standard model will be useful to discriminate the different SUSY models in future B experiments.Comment: revtex4, 36 pages, 10 figure

    Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

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    Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the γp\gamma p centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
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