Mon·Oct 17, 2005Monday·October 17, 2005

1. 01*

   The static quark potential in 2+1 flavour Domain Wall QCD from QCDOC

   Koichi Hashimoto🇯🇵 · Taku Izubuchi🇺🇸 · Jun Noaki (for the RBC-UKQCD Collaborations)🇬🇧

   We report our present status of on-going project on the measurement of the static quark potential in 2+1 flavour domain wall QCD with various improved gauge actions and couplings. Lattice spacing determined from Sommer scale on these ensembles are from 1.6 GeV to 2.0 GeV for $16^3\times 32$ lattice with fifth dimension size 8. We also examine size of discretization error from scaling of a pair of dimensionless quantities, $(r_0{m}_{\pi }{)}^2$ and $r_0{m}_{\rho }$, and found small scaling violation.

   hep-latPoS(2006)·7 citations
2. 02*

   Effects of staggered fermions and mixed actions on the scalar correlator

   S. Prelovsek🇸🇮

   We provide the analytic predictions for the flavor non-singlet scalar correlator, which will enable determination of the scalar meson mass from the lattice scalar correlator. We consider simulations with 2+1 staggered sea quarks and staggered or chiral valence quarks. At small u/d masses the correlator is dominated by the bubble contribution, which is the intermediate state with two pseudoscalar mesons. We determine the bubble contribution within Staggered and Mixed Chiral Perturbation Theory. Its effective mass is smaller than the mass M_pi+M_eta, which is the lightest intermediate state in proper 2+1 QCD. The unphysical effective mass is a consequence of the taste breaking that makes possible the intermediate state with mass 2*M_pi. We find that the scalar correlator can be negative in the simulations with mixed quark actions if the sea and valence quark masses are tuned by matching the pion masses M_{val,val}=M_{pi_5}.

   hep-latPRD(2006)·80 citations
3. 03*

   't Hooft loops and perturbation theory

   Philippe de Forcrand (ETH & CERN)🇨🇭 · Biagio Lucini (ETH)🇨🇭 · David Noth (PSI)🇨🇭

   We show that high-temperature perturbation theory describes extremely well the area law of SU(N) spatial 't Hooft loops, or equivalently the tension of the interface between different Z_N vacua in the deconfined phase. For SU(2), the disagreement between Monte Carlo data and lattice perturbation theory for sigma(T)/T^2 is less than 2%, down to temperatures O(10) T_c. For SU(N), N>3, the ratios of interface tensions, (sigma_k/sigma_1)(T), agree with perturbation theory, which predicts tiny deviations from the ratio of Casimirs, down to nearly T_c. In contrast, individual tensions differ markedly from the perturbative expression. In all cases, the required precision Monte Carlo measurements are made possible by a simple but powerful modification of the 'snake' algorithm.

   hep-latPoS(2006)·24 citations
4. 04*

   Leading twist moments of the neutron structure function F2n

   M. Osipenko🇮🇹 · W. Melnitchouk🇺🇸 · S. Simula🇮🇹 · S. Kulagin🇷🇺 · G. Ricco🇮🇹

   We perform a global analysis of neutron F2n structure function data, obtained by combining proton and deuteron measurements over a large range of kinematics. From these data the lowest moments (n <= 10) of the leading twist neutron F2n structure function are extracted. Particular attention is paid to nuclear effects in the deuteron, which become increasingly important for the higher moments. Our results for the nonsinglet, isovector (p - n) combination of the leading twist moments are used to test recent lattice simulations. We also determine the lowest few moments of the higher twist contributions, and find these to be approximately isospin independent, suggesting the possible dominance of ud correlations over uu and dd in the nucleon.

   ↳ hep-phhep-latnucl-thNPA(2006)·21 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.