20,587 research outputs found

    Cold Compressed Baryonic Matter with Hidden Local Symmetry and Holography

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    I describe a novel phase structure of cold dense baryonic matter predicted in a hidden local symmetry approach anchored on gauge theory and in a holographic dual approach based on the Sakai-Sugimoto model of string theory. This new phase is populated with baryons with half-instanton quantum number in the gravity sector which is dual to half-skyrmion in gauge sector in which chiral symmetry is restored while light-quark hadrons are in the color-confined phase. It is suggested that such a phase that aries at a density above that of normal nuclear matter and below or at the chiral restoration point can have a drastic influence on the properties of hadrons at high density, in particular on short-distance interactions between nucleons, e.g., multi-body forces at short distance and hadrons -- in particular kaons -- propagating in a dense medium. Potentially important consequences on the structure of compact stars will be predicted.Comment: 15 pages, to appear in proceedings of "Strong Coupling Gauge Theories in LHC Era (SCGT09)," Nagoya, Japa

    Magnetic helicity transported by flux emergence and shuffling motions in Solar Active Region NOAA 10930

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    We present a new methodology which can determine magnetic helicity transport by the passage of helical magnetic field lines from sub-photosphere and the shuffling motions of foot-points of preexisting coronal field lines separately. It is well known that only the velocity component which is perpendicular to the magnetic field (υB\upsilon_{\perp B}) has contribution to the helicity accumulation. Here, we demonstrate that υB\upsilon_{\perp B} can be deduced from horizontal motion and vector magnetograms, under a simple relation of υt=μt+υnBnBt\upsilon_t = \mu_t + \frac{\upsilon_n}{B_n} B_t as suggested by Deˊ\acute{e}moulin & Berger (2003). Then after dividing υB\upsilon_{\perp B} into two components, as one is tangential and the other is normal to the solar surface, we can determine both terms of helicity transport. Active region (AR) NOAA 10930 is analyzed as an example during its solar disk center passage by using data obtained by the Spectro-Polarimeter and the Narrowband Filter Imager of Solar Optical Telescope on board Hinode. We find that in our calculation, the helicity injection by flux emergence and shuffling motions have the same sign. During the period we studied, the main contribution of helicity accumulation comes from the flux emergence effect, while the dynamic transient evolution comes from the shuffling motions effect. Our observational results further indicate that for this AR, the apparent rotational motion in the following sunspot is the real shuffling motions on solar surface
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