1,824 research outputs found

    Doubly perturbed S3S_3 neutrinos and the s13s_{13} mixing parameter

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    We further study a predictive model for the masses and mixing matrix of three Majorana neutrinos. At zeroth order the model yielded degenerate neutrinos and a generalized ``tribimaximal" mixing matrix. At first order the mass splitting was incorporated and the tribimaximal mixing matrix emerged with very small corrections but with a zero value for the parameter s13s_{13}. In the present paper a different, assumed weaker, perturbation is included which gives a non zero value for s13s_{13} and further corrections to other quantities. These corrections are worked out and their consequences discussed under the simplifying assumption that the conventional CP violation phase vanishes. It is shown that the existing measurements of the parameter s23s_{23} provide strong bounds on s13s_{13} in this model.Comment: 8 page

    Charged Lepton Electric Dipole Moments from TeV Scale Right-handed Neutrinos

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    We study the connection between charged lepton electric dipole moments, dld_l (l=e,μ,τ)(l=e,\mu,\tau), and seesaw neutrino mass generation in a simple two Higgs doublet extension of the Standard Model plus three right-handed neutrinos (RHN) NaN_a, a=1,2,3a=1,2,3. For RHN with hierarchical masses and at least one with mass in the 10 TeV range we obtain the upper bounds of de<9×1030|d_e|< 9\times 10^{-30} e-cm and dμ<2×1026|d_{\mu}|<2 \times 10^{-26} e-cm. Our scenario favors the normal mass hierarchy for the light neutrinos. We also calculated the cross section for e^-e^- \ra W^- W^- in a high luminosity collider with constraints from neutrinoless double beta decay of nuclei included. Among the rare muon decay experiments we find that \mu\ra e\gamma is most sensitive and the upper limit is <8×1013<8\times 10^{-13}.Comment: references added, typos correcte

    Mass and dust in the disk of a spiral lens galaxy

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    Gravitational lensing is a potentially important probe of spiral galaxy structure, but only a few cases of lensing by spiral galaxies are known. We present Hubble Space Telescope and Magellan observations of the two-image quasar PMN J2004-1349, revealing that the lens galaxy is a spiral galaxy. One of the quasar images passes through a spiral arm of the galaxy and suffers 3 magnitudes of V-band extinction. Using simple lens models, we show that the mass quadrupole is well-aligned with the observed galaxy disk. A more detailed model with components representing the bulge and disk gives a bulge-to-disk mass ratio of 0.16 +/- 0.05. The addition of a spherical dark halo, tailored to produce an overall flat rotation curve, does not change this conclusion.Comment: ApJ, in press [9pp, 7 figs

    Chandra Detects a Rapid Flare in the Gravitationally Lensed Mini-BALQSO RX J0911.4+0551

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    The mini Broad Absorption Line (BAL) quasar RX J0911.4+0551 was observed with the Advanced CCD Imaging Spectrometer (ACIS) of the Chandra X-ray Observatory for ~ 29 ks as part of a gravitational lens (GL) survey aimed at measuring time-delays. Timing analysis of the light-curve of the lensed image A2 shows a rapid flux variation with a duration of about 2000s. A Kolmogorov-Smirnov test shows that the probability that a constant-intensity source would produce the observed variability is less than ~ 0.2 percent. We discuss possible origins for the observed short-term X-ray variability. Our gravitational lens models for the RX J0911.4+0551 GL system predict a time-delay of less than a day between images A1 and A2. The rapid variability combined with the predicted short-time delay make RX J0911.4+0551 an ideal system to apply the GL method for estimating the Hubble constant. We describe the prospects of measuring H_0 within single X-ray observations of GL systems with relatively short time delays. Modeling of the spectrum of the mini-BAL quasar RX J0911.4+0551 suggests the presence of an intrinsic absorber. Partial covering models are slightly preferred over models that contain absorption due to intrinsic ionized or neutral gas.Comment: 17 pages, includes 5 figures, Accepted for publication in Ap

    What are the interactions in quantum glasses?

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    The form of the low-temperature interactions between defects in neutral glasses is reconsidered. We analyse the case where the defects can be modelled either as simple 2-level tunneling systems, or tunneling rotational impurities. The coupling to strain fields is determined up to 2nd order in the displacement field. It is shown that the linear coupling generates not only the usual 1/r31/r^3 Ising-like interaction between the rotational tunneling defect modes, which cause them to freeze around a temperature TGT_G, but also a random field term. At lower temperatures the inversion symmetric tunneling modes are still active - however the coupling of these to the frozen rotational modes, now via the 2nd-order coupling to phonons, generates another random field term acting on the inversion symmetric modes (as well as shorter-range 1/r51/r^5 interactions between them). Detailed expressions for all these couplings are given.Comment: 12 pages, 2 figures. Minor modifications, published versio

    The ρ±ρ0\rho^{\pm}-\rho^0 Mass Splitting Problem

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    It is discussed the problem of the ρ±ρ0\rho^\pm-\rho^0 mass splitting. It is suggested to use the ϕρπ3π\phi\to\rho\pi\to 3\pi decay to measure the ρ±ρ0\rho^{\pm}-\rho^0 mass splitting.Comment: 7 pages, revtex, a few typos fixed, to be published in Pis'ma v ZHETF, V. 69, No 1, pp. 8-11, 10 January 199
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