We use lattice methods to evaluate from first principles the spectrum of hybrid mesons produced by gluonic excitations in quenched QCD with quark masses near the strange quark mass. For the ...spin-exotic mesons with
J
PC
= 1
−+, 0
+−, and 2
+− which are not present in the quark model, we determine the lightest state to be 1
−+ with mass of 2.0(2) GeV.
We determine the masses of the light and the strange quarks in the
MS
-scheme using our high-statistics lattice simulation of QCD with dynamical Wilson fermions. For the light quark mass we find
m
...light
MS
(2
GeV) = 2.7 (2)
MeV
, which is lower than in quenched simulations. For the strange quark, in a sea of two dynamical light quarks, we obtain
m
strange
MS
(2
GeV) = 140(20)
MeV
.
Results from two studies of full QCD with two flavours of dynamical Wilson fermions are presented. At
β = 5.6, the region
0.83
>
m
x
m
p
>
0.56
at
m
x
a
>
(
0.23
L
)
−
1
is explored. The SESAM ...collaboration has generated ensembles of about 200 statistically independent configurations on a 16
3 × 32-lattice at three different
k-values and is entering the final phase of data analysis. The T
χL simulation on a 24
3 × 40-lattice at two
k-values has reached half statistics and data analysis has started recently, hence most results presented here are preliminary. The focus of this report is threefold: (
i) we demonstrate that algorithmic improvements like fast Krylov solvers and parallel preconditioning recently introduced can be put into practise in full QCD simulations, (
ii) we present encouraging observations as to the critical dynamics of the Hybrid Monte Carlo algorithm in the approach to the chiral limit, (
iii) we mention signal improvements of noisy estimator techniques for disconnected diagrams to the
π-
N σ term, and (iv) we report on SESAM's results for light hadron spectrum, light quark masses, and heavy quarkonia.
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