Wed·Oct 3, 2001Wednesday·October 3, 2001

1. 01*

   Topology and Confinement in SU(N) Gauge Theories

   B. Lucini🇬🇧 · M. Teper🇬🇧

   The large N limit of SU(N) gauge theories in 3+1 dimensions is investigated on the lattice by extrapolating results obtained for $2\le N\le 5$. A numerical determination of the masses of the lowest-lying glueball states and of the topological susceptibility in the limit $N\to \infty$ is provided. Ratios of the tensions of stable k-strings over the tension of the fundamental string are investigated in various regimes and the results are compared with expectations based on several scenarios -- in particular MQCD and Casimir scaling. While not conclusive at zero temperature in D=3+1, in the other cases investigated our data seem to favour the latter.

   hep-lathep-phhep-thNucl.Phys.B Proc.Suppl.(2002)·6 citations
2. 02*

   Understanding chiral symmetry breaking with the overlap action

   Thomas DeGrand🇺🇸

   A chiral fermion action allows one to do very clean studies of chiral symmetry breaking in QCD. I will briefly describe how to compute with the overlap action (relatively) cheaply, and then turn to physics: Low modes of the Dirac operator show a ``lumped'' chiral density which peaks at the locations of instantons and anti-instantons. These modes dominate correlation functions at small quark mass in many channels. The picture qualitatively (and in some cases quantitatively) resembles an instanton liquid model.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·1 citation
3. 03*

   Matrix elements of (delta S=2) operators with Wilson fermions

   D.Becirevic🇮🇹 · Ph.Boucaud🇫🇷 · V.Gimenez🇪🇸 · V.Lubicz🇮🇹 · G.Martinelli🇮🇹 · M.Papinutto🇮🇹

   We test the recent proposal of using the Ward identities to compute the K0-K0bar mixing amplitude with Wilson fermions, without the problem of spurious lattice subtractions. From our simulations, we observe no difference between the results obtained with and without subtractions. In addition, from the standard study of the complete set of (delta S=2) operators, we quote the following (preliminary) results (in the MS(NDR) scheme): Bk(2 GeV)=0.70(10), < O7^{3/2}>_{K->pi pi} = 0.10(2)(1) GeV^3, < O8^{3/2}>_{K->pi pi} = 0.49(6)(0) GeV^3.

   hep-lathep-exhep-phNucl.Phys.B Proc.Suppl.(2002)·9 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.