Tue·Oct 7, 2003Tuesday·October 7, 2003

1. 01*

   Lattice study of exotic S=+1 baryon

   Shoichi Sasaki (Univ. of Tokyo)🇯🇵

   We propose S=+1 baryon interpolating operators, which are based on an exotic description of the antidecuplet baryon like diquark-diqaurk-antiquark. By using one of the new operators, the mass spectrum of the spin-1/2 pentaquark states is calculated in quenched lattice QCD at $\beta =6/g^2=6.2$ on a $32^3\times 48$ lattice. It is found that the $J^P$ assignment of the lowest $\Theta (uudd\bar{s})$ state is most likely $(1/2{)}^{-}$. We also calculate the mass of the charm analog of the $\Theta$ and find that the ${\Theta }_c(uudd\bar{c})$ state lies much higher than the $DN$ threshold, in contrast to several model predictions.

   hep-lathep-phPRL(2004)·239 citations
2. 02*

   Lattice QCD on Earth Simulator

   S.Aoki🇯🇵 · K.-I.Ishikawa🇯🇵 · Y.Iwasaki🇯🇵 · K.Kanaya🇯🇵 · T.Kaneko🇯🇵 · Y.Kuramashi🇯🇵 · N.Tsutsui🇯🇵 · A.Ukawa🇯🇵 · T.Yoshie🇯🇵

   We report on coding and performance of our polynomial hybrid Monte Carlo program on the Earth Simulator. At present the entire program achieves 25--40% efficiency. An analysis of overheads shows that a tuning of inter-node communications is required for further improvement.

   hep-latNucl.Phys.B Proc.Suppl.(2004)·6 citations
3. 03*

   A More Improved Lattice Action for Heavy Quarks

   M.B. Oktay🇺🇸 · A.X. El-Khadra🇺🇸 · A.S. Kronfeld🇺🇸 · P.B. Mackenzie🇺🇸

   We extend the Fermilab formalism for heavy quarks to develop a more improved action. We give results of matching calculations of the improvement couplings at tree level. Finally, we estimate the discretization errors associated with the new action.

   hep-latNucl.Phys.B Proc.Suppl.(2004)·15 citations
4. 04*

   Unfactorizing Polychromatic Penguins

   Santi Peris (UAB, Barcelona)🇪🇸

   Firstly, I report on a recent work --carried out with T. Hambye and E. de Rafael-- on how to use the large-Nc expansion to calculate unfactorized contributions from the strong penguin operators, and their impact on observables such as epsilon'/epsilon and the Delta I = 1/2 rule. Secondly, based on work done with M. Golterman, I explain how this calculation allows one to predict some rather dramatic consequences for quenched QCD. This may help explain the present discrepancy between lattice and experimental results for epsilon'/epsilon. The emphasis of this article is put on the explanation of the method of calculation used, which is fully analytic. This allows one to build some intuition and understand the role played by the different hadronic scales in determining the size of the different contributions.

   ↳ hep-phhep-latNucl.Phys.B Proc.Suppl.(2004)·7 citations
5. 05*

   Status of the computation of fBs, fBd, xi and g

   Damir Becirevic🇫🇷

   Current status of the computation of the neutral B-meson mixing amplitudes, with particular attention to the heavy-light meson decay constants, is reviewed. The values for these quantities, as well as for the coupling of the pion to the lowest doublet of heavy-light mesons, are given.

   ↳ hep-phhep-exhep-lateConf(2003)·36 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.