The Spectrum of Kaon States in the Isodoublet strangeness S = 1 T_1u Channel by the Stochastic LapH Method in Lattice QCD

Lattice QCD calculations of energies in bosonic channels have mostly been restricted
to the use of quark-antiquark meson operators due to the computational
challenges associated with evaluating correlation functions of multi-meson operators.
The stochastic LapH method has provided an efficient way to compute correlation
functions involving multi-hadron operators. This method is applied to construct a
58x58 correlation matrix using 9 single-meson operators and 49 two-meson operators
in the isodoublet strangeness S = 1 T_1u channel, which contains the spin-1 and spin-3
kaon states. The matrix of temporal correlations is evaluated using a Monte Carlo
ensemble of 551 configurations on an anisotropic 24³ x 128 lattice. Due to computational
limitations, light quark masses are used that produce an unphysically heavy
pion having a mass around 390 MeV, but the strange quark mass is tuned to its physical
value. A clover-improved Wilson fermion action is used in generating the Monte
Carlo ensemble, and the correlators are formed using source and sink operators constructed
out of Laplacian Heaviside smeared quark fields displaced with stout-smeared
gauge links. Overlap factors are used to identify the finite-volume eigenstates that
should evolve into the kaon resonances in infinite volume. These results are compared
to experiment and to results from a previous study for the isovector nonstrange T⁺_1u channel.