30 research outputs found
The static quark potential from the gauge invariant Abelian decomposition
We investigate the relationship between colour confinement and topological
structures derived from the gauge invariant Abelian (Cho-Duan-Ge)
decomposition. This Abelian decomposition is made imposing an isometry on a
colour field which selects the Abelian direction; the principle novelty of
our study is that we have defined this field in terms of the eigenvectors of
the Wilson Loop. This allows us to establish an equivalence between the path
ordered integral of the non-Abelian gauge fields with an integral over an
Abelian restricted gauge field which is tractable both theoretically and
numerically in lattice QCD. By using Stokes' theorem, we can relate the Wilson
Loop in terms of a surface integral over a restricted field strength, and show
that the restricted field strength may be dominated by topological structures,
which occur when one of the parameters parametrising the colour field winds
itself around a non-analyticity in the colour field. If they exist, these
objects will lead to an area law scaling for the Wilson Loop and provide a
mechanism for quark confinement. We search for these structures in quenched
lattice QCD. We perform the Abelian decomposition, and find that the restricted
field strength is dominated by peaks on the lattice. Wilson Loops containing
these peaks show a stronger area-Law and thus provide the dominant contribution
to the string tension.Comment: 8 pages, 3 figures; v2 some minor changes (including updated
numerical results), accepted for publication in Physics Letter
Update on with lattice QCD inputs
We report updated results for , the indirect CP violation
parameter in neutral kaons, which is evaluated directly from the standard model
with lattice QCD inputs. We use lattice QCD inputs to fix ,
, , , , and . Since Lattice 2016,
the UTfit group has updated the Wolfenstein parameters in the angle-only-fit
method, and the HFLAV group has also updated . Our results show that
the evaluation of with exclusive (lattice QCD
inputs) has tension with the experimental value, while that with
inclusive (heavy quark expansion based on OPE and QCD sum rules)
shows no tension.Comment: 8 pages, 7 figures, Lattice 2017 proceeding, references update
Update on form factor at zero-recoil using the Oktay-Kronfeld action
We present an update on the calculation of
semileptonic form factor at zero recoil using the Oktay-Kronfeld bottom and
charm quarks on flavor HISQ ensembles generated by the MILC
collaboration. Preliminary results are given for two ensembles with and fm and MeV. Calculations have been done
with a number of valence quark masses, and the dependence of the form factor on
them is investigated on the fm ensemble. The excited state is
controlled by using multistate fits to the three-point correlators measured at
4--6 source-sink separations.Comment: 7 pages and 4 figures. Talk at The 36th Annual International
Symposium on Lattice Field Theory - LATTICE201