Mon·Oct 21, 2002Monday·October 21, 2002

1. 01*

   Perturbative Wilson loops with massive sea quarks on the lattice

   Gunnar S. Bali (Glasgow)🇬🇧 · Peter Boyle (Columbia and Edinburgh)🇺🇸

   We present O(g^4) calculations of both planar and non-planar Wilson loops for various actions in the presence of sea quarks. In particular, the plaquette, the static potential and the static self energy are calculated to this order for massive Wilson, Sheikholeslami-Wohlert and Kogut-Susskind fermions, including the mass and n_f dependence. The results can be used to obtain alpha_{MS} and m_b(m_b) from lattice simulations. We compare our perturbative calculations to simulation data of the static potential and report excellent qualitative agreement with boosted perturbation theory predictions for distances r<1/GeV. We are also able to resolve differences in the running of the coupling between n_f=2 and n_f=0 static potentials. We compute perturbative estimates of the ``beta-shifts'' of QCD with sea quarks, relative to the quenched theory, which we find to agree within 10 % with non-perturbative simulations. This is done by matching the respective static potentials at large distances. The prospects of determining the QCD running coupling from low energy hadron phenomenology in the near future are assessed. We obtain the result ${\Lambda }_{\overline{MS}}^{(2)}{r}_0=0.69(15)$ for the two flavour QCD Lambda-parameter from presently available lattice data where $r_0^{-1}\approx 400$ MeV and estimate ${\alpha }_{\overline{MS}}^{(5)}(m_Z)=0.1133(59)$.

   hep-lathep-phnucl-th33 citations
2. 02*

   Status of and performance estimates for QCDOC

   P. Boyle🇬🇧 · D. Chen · N.H. Christ🇺🇸 · C. Cristian🇺🇸 · Z. Dong🇺🇸 · A. Gara🇺🇸 · B. Joo🇬🇧 · C. Jung🇺🇸 · C. Kim🇺🇸 · L. Levkova🇺🇸 · X. Liao🇺🇸 · G. Liu🇺🇸 and 5 other authors

   QCDOC is a supercomputer designed for high scalability at a low cost per node. We discuss the status of the project and provide performance estimates for large machines obtained from cycle accurate simulation of the QCDOC ASIC.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·7 citations
3. 03*

   Heavy Quark Physics and Lattice QCD

   Norikazu Yamada🇯🇵

   I review recent progress made on heavy quark physics on the lattice.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·45 citations
4. 04*

   Speeding up the HMC: QCD with Clover-Improved Wilson Fermions

   M. Hasenbusch🇩🇪 · K. Jansen🇩🇪

   We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of systems with dynamical fermions to two flavor QCD with clover-improvement. For our smallest quark masses we see a speed-up of more than a factor of two compared with the standard algorithm.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·7 citations
5. 05*

   The QCD phase diagram for small chemical potentials

   C. Schmidt🇩🇪

   We compute derivatives of thermodynamic quantities with respect to $\mu$, at $\mu =0$ for 2 and 3 flavors of degenerate quark masses. This allows us to estimate the phase transition line in the $T,\mu$ plane and quantify the influence of a non vanishing chemical potential on the equation of state by computing lines of constant energy, pressure and density. Moreover we evaluate the order of the QCD phase transition by measuring the Binder Cumulant of the chiral condensate. This gives access to the chiral critical point on the phase transition line.

   hep-lat5 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.