arXiv subjects
Publications and source records attributed to U. Heller.
The fourth root approximation in LQCD simulations with dynamical staggered fermions requires justification. We test its validity numerically in the interacting theory in a renormalization group framework.
We compute the strange quark mass $m_s$ and the average of the $u$ and $d$ quark masses $\hat m$ using full lattice QCD with three dynamical quarks combined with experimental values for the pion and kaon masses. The simulations have degenerate $u$ and $d$ quarks with masses $m_u=m_d\equiv \hat m$ as low as $m_s/8$, and two different values of the lattice spacing. The bare lattice quark masses obtained are converted to the $\msbar$ scheme using perturbation theory at $O(alpha_s)$. Our results are: $m_s^\msbar$(2 GeV) = 76(0)(3)(7)(0) MeV, $\hat m^\msbar$(2 GeV) = 2.8(0)(1)(3)(0) MeV and $m_s/\hat m$ = 27.4(1)(4)(0)(1), where the errors are from statistics, simulation, perturbation theory, and electromagnetic effects, respectively.
We describe two calculations involving P-wave mesons made of Wilson quarks: the strong coupling constant $α_s$ in the presence of two flavors of light dynamical fermions and the mass and decay constant of the $a_1$ meson.