Updates

09 - 16 - 2013

Paper "Nonperturbative renormalization for improved staggered bilinears" published in Phys. Rev. D. Also available on the arXiv.

07 - 19 - 2012

Talk by A. Lytle at 2012 Lattice Conference, containing updated results for bilinear Z-factors and comparison with 1-loop perturbation theory. Results are now for the entire momentum range and on coarse and fine MILC lattices. Also, first results using S-MOM scheme for scalar bilinears.

03 - 9 - 2012

Proposal submitted for 2.5 M Jpsi-hours on the clusters at FNAL. (Granted 2.34 M Jpsi-hours.) Contains new results for (a) momentum dependence of ratios of Z-factors; (b) a first comparison of these ratios on fine and coarse lattices; and (c) the first results for the scalar and pseudoscalar bilinears on the coarse lattices with non-exceptional momenta.

07 - 16 - 2011

Talk by S. Sharpe at 2011 Lattice Conference, containing updated results for bilinear Z-factors and comparison with 1-loop perturbation theory.

05 - 7 - 2011

Talk at 2011 All Hands meeting. Second half concerns this project.

03 - 11 - 2011

Proposal submitted for 2.5 M Jpsi-hours on the clusters at FNAL. Contains preliminary results on matching factors for all hypercube bilinears for asqtad and HYP valence quarks. Proposal awarded 2.42 M Jpsi-equivalent core-hrs.

09 - 01 - 2010

Andrew Lytle's thesis, which gives detailed background to the present calculations, and many results, including a result for Z_m from coarse and fine lattices.

05 - 01 - 2010

Presentation on proposal at USQCD All Hands meeting, April 16th 2010.

03 - 01 - 2010

Renewal proposal submitted.

12 - 31 - 2009

We have now included vector bilinear vertices, both the hypercube version (which is the conserved current for naive or HYP-smeared staggered fermions), and the asqtad conserved current (which gives a second method of calculating Z_q).

09 - 01 - 2009

Preliminary analysis on coarse lattices completed, and presented at Lattice 2009. For write-up, see here. We find that the strange-quark mass in the MS-bar scheme at 2 GeV is 106(6) MeV, to be compared to the 84(5) MeV obtained using 2-loop matching. These results are not directly comparable, since they contain different $O(a^2\Lambda_{\rm QCD}^)$ corrections. To study this, we need at least one further lattice spacing.

03 - 20 - 2009

Status report is contained in our renewal proposal submitted to USQCD. Running is now focusing on fine lattices, in order to compare $Z_m$ with that obtained on the coarse lattices.

10 - 20 - 2008

Tuning runs on coarse MILC lattices underway, using asqtad valence quarks, and calculating Zq, ZS and ZP for a variety of momenta and quark masses.

Proposals Summary