Lattice2010

Session

Parallel 24: Chiral symmetry

15 Jun 2010, 10:30

Villasimius, Sardinia

181. Results for light pseudoscalar mesons

Claude Bernard (Washington University)

15/06/2010, 10:30

Chiral symmetry

We present results from the MILC collaboration's analysis of the light pseudoscalar meson sector. All of our asqtad staggered ensembles with 2+1 dynamical quark flavors have now been completed and analyzed, including lattice spacings down to 0.045 fm, and light quark masses down to 0.05 times the strange mass. We compare the results from SU(3) and SU(2) chiral perturbation theory; both...

159. Let's go dynamic -- a quick tour through 2+1 lattice simulations to understand chiral symmetry breaking

Sebastien Descotes-Genon (LPT (CNRS/Univ. Paris-Sud 11))

15/06/2010, 10:50

Chiral symmetry

Several lattice collaboration performing simulations with 2+1 light dynamical quarks have experienced difficulties in fitting their data with conventional NNLO expressions from N_f=3 Chiral Perturbation Theory, even for quantities as simple as pseudoscalar masses and decay constants. At the same time, they have obtained rather small values of the quark condensate and/or the decay constant in...

39. Analysis of the $N_f=2+1$ lattice QCD results on the lowest-lying baryon masses using covariant ChPT

Jorge Martin Camalich (IFIC-Valencia)

15/06/2010, 11:10

Chiral symmetry

We present an analysis of the baryon-octet and -decuplet masses using covariant SU(3)-flavor chiral perturbation theory up to next-to-leading order. Besides the description of the physical masses we address the problem of the lattice QCD extrapolation. More precisely, we study the $N_f=2+1$ results recently provided by the PACS-CS, LHPC and HSC collaborations. We show that a good description...

23. Axial and Electromagnetic observables of hyperons in 2-flavor chiral perturbation theory

Fu-Jiun Jiang (CTP, MIT)

15/06/2010, 11:30

Chiral symmetry

Using two-flavor chiral perturbation theories for hyperons, we study the chiral corrections to the axial charges as well as the electromagnetic properties of spin-1/2 hyperons. We first demonstrate that the virtual kaon loop contributions are well described in the two-flavor theories by terms analytic in the pion mass squared. We further show for the case of experimentally known hyperon...

142. Progress in Electromagnetic Corrections to Staggered Chiral Perturbation Theory

Elizabeth Freeland (Washington University in St. Louis)

15/06/2010, 11:50

Chiral symmetry

To reduce errors in light-quark mass determinations from the lattice, it is now necessary to consider electromagnetic contributions to light-meson masses. Calculations with quenched photons are currently underway, and suitably-extended chiral perturbation theory is necessary to extrapolate the lattice data to the physical limit. We discuss issues of including electromagnetism on the lattice...

254. Topological charge in two flavors QCD with optimal domain-wall fermion

Tung-Han Hsieh (Research Center for Applied Sciences, Academia Sinica)

15/06/2010, 12:10

Chiral symmetry

We determine the topological charge and its fluctuations for the gauge configurations generated by lattice simulations of 2 flavors QCD with optimal domain-wall fermion, on a $ 16^3 \times 32 \times 16 $ lattice with Wilson gauge action at $ \beta = 5.90 $. We project the low-lying modes of the lattice Dirac operator with the Lanczos thick-restart algorithm, and obtain the topological charge,...