Tue·Sep 9, 2003Tuesday·September 9, 2003

1. 01*

   Nucleon mass, sigma term and lattice QCD

   M. Procura (1 and 2)🇩🇪 · T.R. Hemmert (1)🇩🇪 · W. Weise (1 and 2) ((1) TU Muenchen, (2) ECT Trento)🇩🇪

   We investigate the quark mass dependence of the nucleon mass M_N. An interpolation of this observable, between a selected set of fully dynamical two-flavor lattice QCD data and its physical value, is studied using relativistic baryon chiral perturbation theory up to order p^4. In order to minimize uncertainties due to lattice discretization and finite volume effects our numerical analysis takes into account only simulations performed with lattice spacings a<0.15 fm and m_pi L>5. We have also restricted ourselves to data with m_pi<600 MeV and m_sea=m_val. A good interpolation function is found already at one-loop level and chiral order p^3. We show that the next-to-leading one-loop corrections are small. From the p^4 numerical analysis we deduce the nucleon mass in the chiral limit, M_0 approx 0.88 GeV, and the pion-nucleon sigma term sigma_N= (49 +/- 3) MeV at the physical value of the pion mass.

   hep-latPRD(2004)·147 citations
2. 02*

   Geometry of the monopole clusters at different scales

   V.G. Bornyakov🇷🇺 · P.Yu. Boyko🇷🇺 · M.I. Polikarpov🇷🇺 · V.I. Zakharov🇩🇪

   We present results of measurements of various geometrical characteristics of the monopole clusters in the maximally Abelian projection of SU(2) lattice gauge theory. We observe scaling for the observables tested. Short clusters correspond to random walks at small scale but have long-range correlations at the hadronic scale. On the other hand, the percolating cluster at the hadronic scale does not correspond to a random walk.

   hep-latNucl.Phys.B Proc.Suppl.(2004)·3 citations
3. 03*

   Solving the local cohomology problem in U(1) chiral gauge theories within a finite lattice

   D. Kadoh🇯🇵 · Y. Kikukawa🇯🇵 · Y. Nakayama🇯🇵

   In the gauge-invariant construction of abelian chiral gauge theories on the lattice based on the Ginsparg-Wilson relation, the gauge anomaly is topological and its cohomologically trivial part plays the role of the local counter term. We give a prescription to solve the local cohomology problem within a finite lattice by reformulating the Poincaré lemma so that it holds true on the finite lattice up to exponentially small corrections. We then argue that the path-integral measure of Weyl fermions can be constructed directly from the quantities defined on the finite lattice.

   hep-latJHEP(2004)·16 citations
4. 04*

   On the non-Abelian Stokes theorem for SU(2) gauge fields

   F.V.Gubarev🇷🇺

   We derive a version of non-Abelian Stokes theorem for SU(2) gauge fields in which neither additional integration nor surface ordering are required. The path ordering is eliminated by introducing the instantaneous color orientation of the flux. We also derive the non-Abelian Stokes theorem on the lattice and discuss various terms contributing to the trace of the Wilson loop.

   hep-lathep-phPRD(2004)·8 citations
5. 05*

   On the non-Abelian Stokes theorem in SU(2) gluodynamics

   F.Gubarev🇷🇺

   We discuss the non-Abelian Stokes theorem for SU(2) gauge fields which avoids both additional integration variables and surface ordering. The idea is to introduce the instant color orientation of the flux piercing the loop. The non-Abelian Stokes theorem is also considered on the lattice and various terms contributing to the trace of the Wilson loop are discussed.

   hep-latNucl.Phys.B Proc.Suppl.(2004)·0 citations
6. 06*

   Chiral Limit of Strongly Coupled Lattice QCD at Finite Temperatures

   Shailesh Chandrasekharan🇺🇸 · Fu-Jiun Jiang (Duke University)🇺🇸

   We use the recently proposed directed-path algorithm to study the chiral limit of strongly coupled lattice QCD with staggered quarks at finite temperatures. The new algorithm allows us to compute the chiral susceptibility and the pion decay constant accurately on large lattices for massless quarks. In the low temperature phase we find clear evidence for the singularities predicted by chiral perturbation theory. We also show convincingly that the chiral phase transition is of second order and belongs to the O(2) universality class.

   hep-latcond-mathep-phPRD(2003)·35 citations
7. 07*

   Kaon B Parameter in Quenched QCD

   Thomas DeGrand (MILC collaboration)🇺🇸

   I calculate the kaon B-parameter with a lattice simulation in quenched approximation. The lattice simulation uses an action possessing exact lattice chiral symmetry, an overlap action. Computations are performed at two lattice spacings, about 0.13 and 0.09 fm (parameterized by Wilson gauge action couplings beta=5.9 and 6.1) with nearly the same physical volumes and quark masses. I describe particular potential difficulties which arise due to the use of such a lattice action in finite volume. My results are consistent with other recent lattice determinations using domain-wall fermions.

   hep-latPRD(2004)·58 citations
8. 08*

   Analytic properties of the Landau gauge gluon and quark propagators

   R. Alkofer🇩🇪 · W. Detmold🇺🇸 · C. S. Fischer🇩🇪 · P. Maris🇩🇪

   We explore the analytic structure of the gluon and quark propagators of Landau gauge QCD from numerical solutions of the coupled system of renormalized Dyson--Schwinger equations and from fits to lattice data. We find sizable negative norm contributions in the transverse gluon propagator indicating the absence of the transverse gluon from the physical spectrum. A simple analytic structure for the gluon propagator is proposed. For the quark propagator we find evidence for a mass-like singularity on the real timelike momentum axis, with a mass of 350 to 500 MeV. Within the employed Green's functions approach we identify a crucial term in the quark-gluon vertex that leads to a positive definite Schwinger function for the quark propagator.

   ↳ hep-phhep-latPRD(2004)·326 citations
9. 09*

   Analytic structure of the gluon and quark propagators in Landau gauge QCD

   R. Alkofer🇩🇪 · W. Detmold🇺🇸 · C. S. Fischer🇩🇪 · P. Maris🇩🇪

   In Landau gauge QCD the infrared behavior of the propagator of transverse gluons can be analytically determined to be a power law from Dyson-Schwinger equations. This propagator clearly shows positivity violation, indicating the absence of the transverse gluons from the physical spectrum, i.e. gluon confinement. A simple analytic structure for the gluon propagator is proposed capturing all important features. We provide arguments that the Landau gauge quark propagator possesses a singularity on the real timelike axis. For this propagator we find a positive definite Schwinger function.

   ↳ hep-phhep-lathep-thnucl-thNucl.Phys.B Proc.Suppl.(2005)·63 citations

* 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.