Speaker
Description
We present a lattice QCD study of the $K^*(892)$ resonance using
eight $N_f=2+1$ Wilson-Clover ensembles with three lattice spacings
and six pion masses ranging from 135 to 320 MeV. For each ensemble,
a large number of finite volume energy levels in the $P$-wave $K\pi$
channel are determined. The energy dependence of the scattering
phase shift is then obtained from L\"uscher’s finite-volume
method. To systematically assess parametrization dependence, the
amplitude is described using three different models, which yield
consistent results. The resulting phase shifts show a clear resonant
behavior for all ensembles, and the corresponding $K^*(892)$
resonance pole is identified on the second Riemann sheet in the
complex energy plane. The pole positions are extrapolated to the
physical pion mass and the continuum limit, yielding a $K^*(892)$
resonance located at $\sqrt{s_0} = [883.0(6.9) -i20.1(2.2)]\mathrm{ MeV}$,
which is in excellent agreement with the experimental value. This
study provides a first-principles QCD determination of the
$K^*(892)$ mass and width with estimated systematic uncertainties.
