Tue·Nov 27, 2007Tuesday·November 27, 2007

1. 01*

   Simulations of one-flavor QCD at finite temperature by RHMC

   Tetsuya Takaishi🇯🇵 · Atsushi Nakamura🇯🇵

   We simulate one-flavor QCD with standard Wilson fermions at finite temperature by the rational hybrid Monte Carlo algorithm. In the heavy quark region when we decrease the quark mass there is an endpoint which terminates the first order phase transition. We try to locate it by calculating the Binder cumulant of the Polyakov loop norm. We estimate the end-point to be kappa_c \sim 0.07-0.08.

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

   Nf=2+1 dynamical Wilson quark simulation toward the physical point

   Yoshinobu Kuramashi🇯🇵

   We present preliminary results of the PACS-CS project which simulates 2+1 flavor lattice QCD toward the physical point with the nonperturbatively O(a)-improved Wilson quark action and the Iwasaki gauge action. Calculations are carried out at beta=1.9 on a 32^3x64 lattice with the use of the domain-decomposed HMC algorithm to reduce the up-down quark mass. The resulting pseudoscalar meson masses range from 730 MeV down to 210 MeV. We discuss the physical results including the chiral analysis in the pseudoscalar meson sector and the hadron spectrum. Some algorithmic issues are also discussed.

   hep-latPoS(2007)·12 citations
3. 03*

   K to pi pi Amplitudes at Unphysical Kinematics Using Domain Wall Fermions

   Matthew Lightman🇺🇸

   The use of chiral perturbation theory in extracting physical K to pi pi matrix elements from matrix elements calculated at unphysical kinematics is outlined. In particular, the possibility of utilizing pions with non-zero momentum in the final state, and of using partial quenching is discussed. Preliminary (not physically normalized) Delta I=3/2 (27,1) K to pi pi matrix elements are calculated on the RBC/UKQCD $24^3\times 64$, $L_s=16$ lattices, using 2+1 dynamical flavors and domain wall fermions, with an inverse lattice spacing of $a^{-1}=1.729(28)GeV$. Effective mass plots are presented for a light sea quark mass of $m_l^{sea}=0.005$, and various valence quark masses. The plateaux are fit and $E_{\pi \pi }-m_K$ is extracted.

   hep-latPoS(2007)·0 citations
4. 04*

   The Spectral Structure of Correlator Matrices

   Adam C. Lichtl🇺🇸

   In lattice QCD spectrum calculations, it is desirable to obtain multiple excited state energies in each symmetry channel. Typically, one constructs several interpolating operators for the symmetry channel of interest, forms the `correlator matrix' of all possible two-point functions, and uses the variational method to obtain as many energy levels as possible. We present a detailed look at this last step, starting from a discussion of the symmetry properties and spectral structure of the correlator matrix. We continue by motivating and describing the variational method, before discussing some conceptual and practical challenges concerning the light baryon sector. We conclude by mentioning some alternate spectrum extraction methods currently under study. Throughout, we attempt to quantify all approximations and assumptions, and we illustrate our points using a nucleon correlator matrix estimated on dynamical two-flavor lattice data.

   hep-latPoS(2007)·3 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.