Origin of metallicity in atomic Ag wires on Si(557)

We investigated the metallicity of Ag-root 3 ordered atomic wires close to one monolayer (ML) coverage, which are formed on Si(557) via self assembly. For this purpose we combined high resolution electron energy loss spectroscopy with tunneling microscopy. By extending the excess Ag coverage up to 0.6 ML on samples annealed at high temperatures where partial desorption occurs, we demonstrate that one-dimensional metallicity in the Ag-root 3 x root 3 R30 degrees ordered atomic wires on the (111) mini-terraces originates only from Ag atoms in excess of (local) monolayer coverage, which are adsorbed and localized at the highly stepped parts of the Si(557) surface. Thus these Ag atoms act as extrinsic dopants on the atomic scale, causing coverage dependent subband filling and increasing localization as a function of doping concentration. The second layer lattice gas as well as Ag islands on the (111) terraces turn out not to be relevant as dopants. We simulated the peculiar saturation behavior within a modified lattice gas model and give evidence that the preparation dependent saturation of doping is due to changes of average terrace size and step morphology induced by high temperature treatment.Niedersächsisches Ministerium für Wissenschaftund KulturDFG/FOR/170

Lattice QCD at the physical point: Simulation and analysis details

We give details of our precise determination of the light quark masses m_{ud}=(m_u+m_d)/2 and m_s in 2+1 flavor QCD, with simulated pion masses down to 120 MeV, at five lattice spacings, and in large volumes. The details concern the action and algorithm employed, the HMC force with HEX smeared clover fermions, the choice of the scale setting procedure and of the input masses. After an overview of the simulation parameters, extensive checks of algorithmic stability, autocorrelation and (practical) ergodicity are reported. To corroborate the good scaling properties of our action, explicit tests of the scaling of hadron masses in N_f=3 QCD are carried out. Details of how we control finite volume effects through dedicated finite volume scaling runs are reported. To check consistency with SU(2) Chiral Perturbation Theory the behavior of M_\pi^2/m_{ud} and F_\pi as a function of m_{ud} is investigated. Details of how we use the RI/MOM procedure with a separate continuum limit of the running of the scalar density R_S(\mu,\mu') are given. This procedure is shown to reproduce the known value of r_0m_s in quenched QCD. Input from dispersion theory is used to split our value of m_{ud} into separate values of m_u and m_d. Finally, our procedure to quantify both systematic and statistical uncertainties is discussed.Comment: 45 page

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Resonant Structure of τ→3ππ0ντ\tau\to 3\pi\pi^{0}\nu_{\tau} and τ→ωπντ\tau\to \omega\pi\nu_{\tau} Decays

The resonant structure of the four pion final state in the decay $\tau \to 3\pi\pi^0\nu_\tau$ is analyzed using 4.27 million $\tau^+\tau^-$ pairs collected by the CLEO II experiment. We search for second class currents in the decay $\tau \to \omega\pi\nu_\tau$ using spin-parity analysis and establish an upper limit on the non-vector current contribution. The mass and width of the $\rho'$ resonance are extracted from a fit to the $\tau \to \omega\pi\nu_\tau$ spectral function. A partial wave analysis of the resonant structure of the $\tau \to 3\pi\pi^0\nu_\tau$ decay is performed; the spectral decomposition of the four pion system is dominated by the $\omega\pi$ and $a_1 \pi$ final states.Comment: 34 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

The registry of the German Network for Systemic Scleroderma: frequency of disease subsets and patterns of organ involvement

Objective. Systemic sclerosis (SSc) is a rare, heterogeneous disease, which affects different organs and therefore requires interdisciplinary diagnostic and therapeutic management. To improve the detection and follow-up of patients presenting with different disease manifestations, an interdisciplinary registry was founded with contributions from different subspecialties involved in the care of patients with SSc