Tue·Sep 20, 2005Tuesday·September 20, 2005

1. 01*

   The hadron spectrum from twisted mass QCD with a strange quark

   Abdou M. Abdel-Rehim🇨🇦 · Randy Lewis🇨🇦 · R. M. Woloshyn🇨🇦

   Various suggestions exist for incorporating the strange quark into twisted mass QCD. One option for quenched simulations is to employ two twisted doublets, (u,d) and (c,s), with separate twist angles. Working in the isospin limit, preliminary results for the quenched spectrum of strange hadrons are presented, with both twist angles tuned to pi/2. Splittings within the mass multiplets provide some insight into the symmetry breaking effects of twisted mass lattice QCD.

   hep-latPoS(2006)·9 citations
2. 02*

   D-branes and Topological Charge in QCD

   H. B. Thacker🇺🇸

   The recently observed long-range coherent structure of topological charge fluctuations in QCD is compared with theoretical expectations based on the AdS/CFT brane construction of nonsupersymmetric gauge theory by Witten. Similar observations of coherent topologicalcharge structure in 2D $C{P}^{N-1}$ sigma models are interpreted in terms of Wilson lines representing world lines of screened electric charges. The analogy between 2D U(1) and 4D Yang-Mills theory leads to the interpretation of the observed coherent sheets of topological charge in QCD as screened ``Wilson bags'' first suggested by Luscher. The duality between the Wilson bag surface and a wrapped 6-brane in IIA string theory is discussed. The complete screening of the force between bag surfaces for integer values of the bag charge $\theta /2\pi$ corresponds to the observation by Polchinski that the net force between d-branes from closed string exchange vanishes for quantized values of Ramond-Ramond charge.

   hep-lathep-thPoS(2006)·5 citations
3. 03*

   Lattice QFT with FermiQCD

   Massimo Di Pierro🇺🇸 · Jonthan M. Flynn🇬🇧

   FermiQCD is a C++ library for fast development of parallel Lattice Quantum Field Theory computations. It has been developed following a top-down fully Object Oriented design approach with focus on simplicity of use. FermiQCD includes: a heatbath algorithm for Wilson and $O(a^2)$ improved SU(n) gauge actions; inversion algorithms for Wilson, Clover, Kogut-Susskind, Asqtad, and Domain Wall fermionic actions; example programs for various types of meson propagators; and converters for the most common gauge file formats.

   hep-latPoS(2006)·13 citations
4. 04*

   Low energy constants from the chirally improved Dirac operator D_CI

   Christof Gattringer🇦🇹 · Philipp Huber🇦🇹 · C. B. Lang🇦🇹

   The leading order low energy parameters like the pion decay constant or the quark condensate are well-known from "classical" low energy theorems and experiments. It is a challenge, however, to find these parameters based exclusively on an ab-initio QCD calculation. We discuss results of a quenched lattice calculation of low energy constants using the chirally improved Dirac operator. Several lattice sizes at different lattice spacings are studied, using pseudoscalar and axial vector correlators. We find consistent results for f_\pi = 96(2) MeV, f_K = 105(2) MeV, \Sigma = -(286(4) MeV)^3, the average light quark mass m = 4.1(2.4) MeV and m_s = 101(8) MeV.

   hep-latPoS(2006)·4 citations
5. 05*

   Two-colour Lattice QCD with dynamical fermions at non-zero density versus Matrix Models

   Gernot Akemann🇬🇧 · Elmar Bittner🇩🇪

   We provide first evidence that Matrix Models describe the low lying complex Dirac eigenvalues in a theory with dynamical fermions at non-zero density. Lattice data for gauge group SU(2) with staggered fermions are compared to detailed analytical results from Matrix Models in the corresponding symmetry class, the complex chiral Symplectic Ensemble. They confirm the predicted dependence on chemical potential, quark mass and volume.

   hep-lathep-thPoS(2006)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.