Thu·Nov 1, 2007Thursday·November 1, 2007

1. 01*

   Fisher's Zeros and Perturbative Series in Gluodynamics

   A. Denbleyker🇺🇸 · D. Du🇺🇸 · Y. Meurice🇺🇸 · A. Velytsky🇺🇸

   We study the zeros of the partition function in the complex beta plane (Fisher's zeros) in SU(2) and SU(3) gluodynamics. We discuss their effects on the asymptotic behavior of the perturbative series for the average plaquette. We present new methods to infer the existence of these zeros in region of the complex beta plane where MC reweighting is not reliable. These methods are based on the assumption that the plaquette distribution can be approximated by a phi^4 type distribution. We give new estimates of the locations for a 4^4 lattice. For SU(2), we found zeros at beta =2.18(1) \pm i0.18(2) (which differs from previous estimates), and at beta =2.18(1) \pm i0.22(2). For SU(3), we confirm beta =5.54(2)\pm i0.10(2) and found additional zeros at beta =5.54(2)\pm i0.16(2). Some of the technical material can be found in recent preprints, in the following we emphasize the motivations (why it is important to know the locations of the zeros) and the challenges (why it is difficult to locate the zeros when the volume increases)

   hep-latPoS(2007)·5 citations
2. 02*

   2+1 flavour Domain Wall Fermion simulations by the RBC and UKQCD collaborations

   Peter Boyle · RBC · UKQCD Collaborations

   We review simulations of dynamical domain wall fermions at a fixed inverse lattice spacing of 1.73GeV and with pion masses as light as 330MeV and spatial dimensions as large as 2.7fm performed by the RBC and UKQCD collaborations. These results include pseudoscalar masses and decay constants and low energy constants of the chiral effective lagrangian. We also review results for the neutral kaon mixing amplitude $B_K$, the Kl3 form factor, pseudoscalar meson structure, and vector meson decay constants. In the baryon sector we review results for the spectrum, and nucleon form factors and structure functions. Highlights of our programme include preliminary quark masses, and determinations of $V_{us}$ from both $f_K/f_{\pi }$ and from Kl3, and an updated result for $B_K$. We find significant finite volume effects in the nucleon axial charge $g_A$ for our $m_{\pi }=330$ MeV ensemble on a $(2.7\mathrm{fm}{)}^3$ lattice, and highlight the importance of large physical volumes for non-trivial nucleon physics.

   hep-latPoS(2007)·22 citations
3. 03*

   Dynamics, Symmetries and Hadron Properties

   I.C. Cloet🇺🇸 · A. Krassnigg🇦🇹 · C.D. Roberts🇺🇸

   We provide a snapshot of Dyson-Schwinger equation applications to the theory and phenomenology of hadrons. Exact results for pseudoscalar mesons are highlighted, with details relating to the U_A(1) problem. Calculated masses of the lightest J=0,1 states are discussed. We recapitulate upon studies of nucleon properties and give a perspective on the contribution of quark orbital angular momentum to the spin of a nucleon at rest.

   ↳ nucl-thhep-lathep-phnucl-exeConf(2007)·52 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.