2,605 research outputs found

    Excited light and strange hadrons from the lattice with two Chirally Improved quarks

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    Results for excited light and strange hadrons from the lattice with two flavors of Chirally Improved sea quarks are presented. We perform simulations at several values of the pion mass ranging from 250 to 600 MeV and extrapolate to the physical pion mass. The variational method is applied to extract excited energy levels but also to discuss the content of the states. Among others, we explore the flavor singlet/octet content of Lambda states. In general, our results agree well with experiment, in particular we confirm the Lambda(1405) and its dominant flavor singlet structure.Comment: Contribution to the XV International Conference on Hadron Spectroscopy "Hadron 2013", 4-8 November 2013, Nara, Japa

    Mitmischen is possible : neugegründete Stadtwerke nutzen die Chancen der Energiewende

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    Die meisten Konzessionsverträge für Strom und Gas auf der örtlichen Verteilnetzebene sind zwischen 2005 und 2016 ausgelaufen. Viele Gemeinden in Deutschland haben dies als Chance verstanden, um mit der Gründung eigener Stadtwerke die örtliche Energieversorgung stärker selbst gestalten zu können. Bei diesem Trend zur Rekommunalisierung waren Städte und Gemeinden mit unter 25.000 Einwohnern besonders stark beteiligt. Im Folgenden sollen die verschiedenen Aspekte der Rekommunalisierung näher betrachtet werden

    Direct determinations of the nucleon and pion σ\sigma terms at nearly physical quark masses

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    We present a high statistics study of the pion and nucleon light and strange quark sigma terms using Nf=2N_f=2 dynamical non-perturbatively improved clover fermions with a range of pion masses down to mπ150m_\pi\sim 150 MeV and several volumes, Lmπ=3.4Lm_\pi=3.4 up to 6.76.7, and lattice spacings, a=0.060.08a=0.06-0.08 fm, enabling a study of finite volume and discretisation effects for mπ260m_\pi\gtrsim 260 MeV. Systematics are found to be reasonably under control. For the nucleon we obtain σπN=35(6)\sigma_{\pi N}=35(6) MeV and σs=35(12)\sigma_s=35(12) MeV, or equivalently in terms of the quark fractions, fTu=0.021(4)f_{T_u}=0.021(4), fTd=0.016(4)f_{T_d}=0.016(4) and fTs=0.037(13)f_{T_s}=0.037(13), where the errors include estimates of both the systematic and statistical uncertainties. These values, together with perturbative matching in the heavy quark limit, lead to fTc=0.075(4)f_{T_c}=0.075(4), fTb=0.072(2)f_{T_b}=0.072(2) and fTt=0.070(1)f_{T_t}=0.070(1). In addition, through the use of the (inverse) Feynman-Hellmann theorem our results for σπN\sigma_{\pi N} are shown to be consistent with the nucleon masses determined in the analysis. For the pion we implement a method which greatly reduces excited state contamination to the scalar matrix elements from states travelling across the temporal boundary. This enables us to demonstrate the Gell-Mann-Oakes-Renner expectation σπ=mπ/2\sigma_\pi=m_\pi/2 over our range of pion masses.Comment: 31 pages, 18 figures, v2, small changes to text and figure

    Generierung und funktionelle Anwendung einer randomisierten sh- und si-RNA Bibliothek

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