Speaker
Description
Preliminary results are presented for nucleon-pion scattering amplitudes in the $I=3/2$ channel. The calculations are performed on a set of $N_\text{f} = 2+1$ Wilson clover ensembles generated by the CLS initiative with pion masses down to $m_\pi = 200\text{MeV}$ where the $\Delta(1232)$ state is unstable. The required hadron correlation functions are efficiently evaluated using the stochastic LapH method. Compared to meson-meson scattering, the temporal correlation matrices employed here require considerably more Wick contractions, each of which is computed by contracting hadron tensors of rank two and three. Our approach to these additional difficulties, which employs highly optimized BLAS libraries for correlation function construction, is also discussed.
