SMMR simulator radiative transfer calibration model. 1: Derivation

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Ring-Pattern Dynamics in Smectic-C* and Smectic-C_A* Freely Suspended Liquid Crystal Films

Ring patterns of concentric 2pi-solitons in molecular orientation, form in freely suspended chiral smectic-C films in response to an in-plane rotating electric field. We present measurements of the zero-field relaxation of ring patterns and of the driven dynamics of ring formation under conditions of synchronous winding, and a simple model which enables their quantitative description in low polarization DOBAMBC. In smectic C_A* TFMHPOBC we observe an odd-even layer number effect, with odd number layer films exhibiting order of magnitude slower relaxation rates than even layer films. We show that this rate difference is due to much larger spontaneous polarization in odd number layer films.Comment: 4 RevTeX pgs, 4 eps figures, submitted to Phys. Rev. Let

Search for T Violation in Charm Meson Decays

Using data from the FOCUS (E831) experiment, we have searched for T violation in charm meson decays using the four-body decay channels $D^0 \to K^-K^+\pi^-\pi^+$, $D^+ \to K^0_SK^+\pi^-\pi^+$, and $D^+_s \to K^0_SK^+\pi^-\pi^+$. The T violation asymmetry is obtained using triple-product correlations and assuming the validity of the CPT theorem. We find the asymmetry values to be $A_Tviol (D^0) = 0.010 \pm 0.057(stat.) \pm 0.037(syst.)$, $A_Tviol (D^+) = 0.023 \pm 0.062(stat.) \pm 0.022(syst.)$, and $A_Tviol (D^+_s) = -0.036 \pm 0.067(stat.) \pm 0.023(syst.)$. Each measurement is consistent with no T violation. New measurements of the CP asymmetries for some of these decay modes are also presented.Comment: 17 pages,6 figures,submitted to Phys.Lett.

High-pressure transport properties of CeRu_2Ge_2

The pressure-induced changes in the temperature-dependent thermopower S(T) and electrical resistivity \rho(T) of CeRu_2Ge_2 are described within the single-site Anderson model. The Ce-ions are treated as impurities and the coherent scattering on different Ce-sites is neglected. Changing the hybridisation \Gamma between the 4f-states and the conduction band accounts for the pressure effect. The transport coefficients are calculated in the non-crossing approximation above the phase boundary line. The theoretical S(T) and \rho(T) curves show many features of the experimental data. The seemingly complicated temperature dependence of S(T) and \rho(T), and their evolution as a function of pressure, is related to the crossovers between various fixed points of the model.Comment: 9 pages, 10 figure

Neutron Star Structure and the Neutron Radius of 208Pb

We study relationships between the neutron-rich skin of a heavy nucleus and the properties of neutron-star crusts. Relativistic effective field theories with a thicker neutron skin in $^{208}$Pb have a larger electron fraction and a lower liquid-to-solid transition density for neutron-rich matter. These properties are determined by the density dependence of the symmetry energy which we vary by adding nonlinear couplings between isoscalar and isovector mesons. An accurate measurement of the neutron radius in $^{208}$Pb---via parity violating electron scattering---may have important implications for the structure of neutron stars.Comment: 5 pages 3 figures, added additional evidence of model independence, Phys. Rev. Letters in pres

The Extended Shapes of Galactic Satellites

We are exploring the extended stellar distributions of Galactic satellite galaxies and globular clusters. For seven objects studied thus far, the observed profile departs from a King function at large r, revealing a ``break population'' of stars. In our sample, the relative density of the ``break'' correlates to the inferred M/L of these objects. We discuss opposing hypotheses for this trend: (1) Higher M/L objects harbor more extended dark matter halos that support secondary, bound, stellar ``halos''. (2) The extended populations around dwarf spheroidals (and some clusters) consist of unbound, extratidal debris from their parent objects, which are undergoing various degrees of tidal disruption. In this scenario, higher M/L ratios reflect higher degrees of virial non-equilibrium in the parent objects, thus invalidating a precept underlying the use of core radial velocities to obtain masses.Comment: 8 pages, including 2 figures Yale Cosmology Workshop: The Shapes of Galaxies and Their Halo

Study of Cabibbo Suppressed Decays of the Ds Charmed-Strange Meson involving a KS

We study the decay of Ds meson into final states involving a Ks and report the discovery of Cabibbo suppressed decay modes Ds -> Kspi-pi+pi+ (179 +/- 36 events) and Ds -> Kspi+ (113 +/-26 events). The branching ratios for the new modes are Gamma(Ds -> Kspi-pi+pi+)/Gamma(Ds -> KsK-pi+pi+) = 0.18 +/- 0.04 +/- 0.05 and Gamma(Ds -> Kspi+)/Gamma(Ds -> KsK+) = 0.104 +/- 0.024 +/- 0.013.Comment: 11 pages, 6 figure

Exploring Halo Substructure with Giant Stars IV: The Extended Structure of the Ursa Minor Dwarf Spheroidal

We present a large area photometric survey of the Ursa Minor dSph. We identify UMi giant star candidates extending to ~3 deg from the center of the dSph. Comparison to previous catalogues of stars within the tidal radius of UMi suggests that our photometric luminosity classification is 100% accurate. Over a large fraction of the survey area, blue horizontal branch stars associated with UMi can also be identified. The spatial distribution of both the UMi giant stars and the BHB stars are remarkably similar, and a large fraction of both samples of stars are found outside the tidal radius of UMi. An isodensity contour map of the stars within the tidal radius of UMi reveals two morphological peculiarities: (1) The highest density of dSph stars is offset from the center of symmetry of the outer isodensity contours. (2) The overall shape of the outer contours appear S-shaped. We find that previously determined King profiles with ~50' tidal radii do not fit well the distribution of our UMi stars. A King profile with a larger tidal radius produces a reasonable fit, however a power law with index -3 provides a better fit for radii > 20'. The existence of UMi stars at large distances from the core of the galaxy, the peculiar morphology of the dSph within its tidal radius, and the shape of its surface density profile all suggest that UMi is evolving significantly due to the tidal influence of the Milky Way. However, the photometric data on UMi stars alone does not allow us to determine if the candidate extratidal stars are now unbound or if they remain bound to the dSph within an extended dark matter halo. (Abridged)Comment: accepted by AJ, 32 pages, 15 figures, emulateapj5 styl

Measurements of Ξc+\Xi_c^{+} Branching Ratios

Using data collected by the fixed target Fermilab experiment FOCUS, we measure the branching ratios of the Cabibbo favored decays $\Xi_c^+ \to \Sigma^+K^-\pi^+$, $\Xi_c^+ \to \Sigma^+ \bar{K}^{*}(892)^0$, and $\Xi_c^+ \to \Lambda^0K^-\pi^+\pi^+$ relative to $\Xi_c^+ \to \Xi^-\pi^+\pi^+$ to be $0.91\pm0.11\pm0.04$, $0.78\pm0.16\pm0.06$, and $0.28\pm0.06\pm0.06$, respectively. We report the first observation of the Cabibbo suppressed decay $\Xi_c^+ \to \Sigma^+K^+K^-$ and we measure the branching ratio relative to $\Xi_c^+ \to \Sigma^+K^-\pi^+$ to be $0.16\pm0.06\pm0.01$. We also set 90% confidence level upper limits for $\Xi_c^+ \to \Sigma^+ \phi$ and $\Xi_c^+ \to \Xi^*(1690)^0(\Sigma^+ K^-) K^+$ relative to $\Xi_c^+ \to \Sigma^+K^-\pi^+$ to be 0.12 and 0.05, respectively. We find an indication of the decays $\Xi_c^+ \to \Omega^-K^{+}\pi^+$ and $\Xi_c^+ \to \Sigma^{*}(1385)^+ \bar{K}^0$ and set 90% confidence level upper limits for the branching ratios with respect to $\Xi_c^+ \to \Xi^-\pi^+\pi^+$ to be 0.12 and 1.72, respectively. Finally, we determine the 90% C.L. upper limit for the resonant contribution $\Xi_c^+ \to \Xi^{*}(1530)^0 \pi^+$ relative to $\Xi_c^+ \to \Xi^-\pi^+\pi^+$ to be 0.10.Comment: 14 pages, 8 figure