Speaker
Description
In this talk, we show the recent status of the rho resonance study in the HAL QCD method.
We investigate the I=1 two-pion potential at $m_{\pi} \approx 411$ MeV by using a new calculation strategy, namely the combination of three techniques: the one-end trick, the sequential propagator, and covariant approximation averaging (CAA).
Thanks to the new strategy, we determine the non-local I=1 two-pion potential at the next-leading-order of the derivative expansion for the first time and obtain the pole of the S-matrix corresponding to the rho resonance.
As regards the resonance parameters, our resonance mass is consistent with the previous study using the finite-volume method, but slightly larger decay width and coupling are obtained. We discuss possible origins of this difference.
