1,786 research outputs found

    Spectroscopy of SrRuO/Ru Junctions in Eutectic

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    We have investigated the tunnelling properties of the interface between superconducting Sr2RuO4 and a single Ru inclusion in eutectic. By using a micro-fabrication technique, we have made Sr2RuO4/Ru junctions on the eutectic system that consists of Sr2RuO4 and Ru micro-inclusions. Such a eutectic system exhibits surface superconductivity, called the 3-K phase. A zero bias conductance peak (ZBCP) was observed in the 3-K phase. We propose to use the onset of the ZBCP to delineate the phase boundary of a time-reversal symmetry breaking state.Comment: To be published in Proc of 24th Int. Conf. on Low Temperature Physics (LT24); 2 page

    Enhanced Peculiar Velocities in Brane-Induced Gravity

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    The mounting evidence for anomalously large peculiar velocities in our Universe presents a challenge for the LCDM paradigm. The recent estimates of the large scale bulk flow by Watkins et al. are inconsistent at the nearly 3 sigma level with LCDM predictions. Meanwhile, Lee and Komatsu have recently estimated that the occurrence of high-velocity merging systems such as the Bullet Cluster (1E0657-57) is unlikely at a 6.5-5.8 sigma level, with an estimated probability between 3.3x10^{-11} and 3.6x10^{-9} in LCDM cosmology. We show that these anomalies are alleviated in a broad class of infrared-modifed gravity theories, called brane-induced gravity, in which gravity becomes higher-dimensional at ultra large distances. These theories include additional scalar forces that enhance gravitational attraction and therefore speed up structure formation at late times and on sufficiently large scales. The peculiar velocities are enhanced by 24-34% compared to standard gravity, with the maximal enhancement nearly consistent at the 2 sigma level with bulk flow observations. The occurrence of the Bullet Cluster in these theories is 10^4 times more probable than in LCDM cosmology.Comment: 15 pages, 6 figures. v2: added reference

    The Sunyaev-Zel'dovich Effect at Five Arc-seconds: RXJ1347.5-1145 Imaged by ALMA

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    We present the first image of the thermal Sunyaev-Zel'dovich effect (SZE) obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combining 7-m and 12-m arrays in Band 3, we create an SZE map toward a galaxy cluster RXJ1347.5-1145 with 5 arc-second resolution (corresponding to the physical size of 20 kpc/h), the highest angular and physical spatial resolutions achieved to date for imaging the SZE, while retaining extended signals out to 40 arc-seconds. The 1-sigma statistical sensitivity of the image is 0.017 mJy/beam or 0.12 mK_CMB at the 5 arc-second full width at half maximum. The SZE image shows a good agreement with an electron pressure map reconstructed independently from the X-ray data and offers a new probe of the small-scale structure of the intracluster medium. Our results demonstrate that ALMA is a powerful instrument for imaging the SZE in compact galaxy clusters with unprecedented angular resolution and sensitivity. As the first report on the detection of the SZE by ALMA, we present detailed analysis procedures including corrections for the missing flux, to provide guiding methods for analyzing and interpreting future SZE images by ALMA.Comment: 20 pages, 13 figures. Accepted for publication in PAS

    Charmonium and meson-molecule hybrid tetraquarks - Vector meson width and the isospin breaking in the X(3872) decay

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    In the X(3872) decay, both of the J/\psi\pi\pi\ and J/\psi\pi\pi\pi\ branching fractions are observed experimentally, and their sizes are comparable to each other. In order to clarify the mechanism to cause such a large isospin violation, we investigate X(3872) employing a model of coupled-channel two-meson scattering with a ccbar core. The two-meson states consist of D0Dbar*0, D+Dbar*-, J/\psi\rho, and J/\psi\omega. The effects of the \rho\ and \omega\ meson width are also taken into account. We calculate the transfer strength from the ccbar core to the final two-meson states. It is found that very narrow J/\psi\rho\ and J/\psi\omega\ peaks appear very close to the D0Dbar*0 threshold for a wide range of variation in the parameter sets. The size of the J/\psi\rho\ peak is almost the same as that of J/\psi\omega, which is consistent with the experiments. The large width of the \rho\ meson makes the originally small isospin violation by about five times larger.Comment: 4 pages, 5figures, proceedings of APFB201

    Radiative decays of heavy and light mesons in a quark triangle approach

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    The radiative meson decays V→PγV\to P\gamma and P→γγP\to \gamma\gamma are analyzed using the quark triangle diagram. Experimental data yield well determined estimates of the universal quark-antiquark-meson couplings gVqqˉ′g_{Vq\bar{q}'} and gPqqˉ′g_{Pq\bar{q}'} for the light meson sector. Also predictions for the ratios of neutral to charged heavy meson decay coupling constants are given and await experimental confirmation.Comment: 31 pages of RevTex, 5 figures, Postscript version available at http://info.utas.edu.au/docs/physics/theory/Publications/9548.html, scheduled to appear in Phys. Rev. D, vol 53, issue 11, 199

    The current status of orbital experiments for UHECR studies

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    Two types of orbital detectors of extreme energy cosmic rays are being developed nowadays: (i) TUS and KLYPVE with reflecting optical systems (mirrors) and (ii) JEM-EUSO with high-transmittance Fresnel lenses. They will cover much larger areas than existing ground-based arrays and almost uniformly monitor the celestial sphere. The TUS detector is the pioneering mission developed in SINP MSU in cooperation with several Russian and foreign institutions. It has relatively small field of view (+/-4.5 deg), which corresponds to a ground area of 6.4x10^3 sq.km. The telescope consists of a Fresnel-type mirror-concentrator (~2 sq.m) and a photo receiver (a matrix of 16x16 photomultiplier tubes). It is to be deployed on the Lomonosov satellite, and is currently at the final stage of preflight tests. Recently, SINP MSU began the KLYPVE project to be installed on board of the Russian segment of the ISS. The optical system of this detector contains a larger primary mirror (10 sq.m), which allows decreasing the energy threshold. The total effective field of view will be at least +/-14 degrees to exceed the annual exposure of the existing ground-based experiments. Several configurations of the detector are being currently considered. Finally, JEM-EUSO is a wide field of view (+/-30 deg) detector. The optics is composed of two curved double-sided Fresnel lenses with 2.65 m external diameter, a precision diffractive middle lens and a pupil. The ultraviolet photons are focused onto the focal surface, which consists of nearly 5000 multi-anode photomultipliers. It is developed by a large international collaboration. All three orbital detectors have multi-purpose character due to continuous monitoring of various atmospheric phenomena. The present status of development of the TUS and KLYPVE missions is reported, and a brief comparison of the projects with JEM-EUSO is given.Comment: 18 pages; based on the rapporteur talk given by M.I. Panasyuk at ECRS-2014; v2: a few minor language issues fixed thanks to the editor; to be published in the proceeding
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