Dr Liuming Liu (University of Bonn)
We present results for the $\pi\pi$ isospin-0 scattering length calculated in twisted mass lattice QCD. We use a set of $N_f = 2 + 1 + 1$ ensembles with pion mass varying in the range of 230MeV - 510MeV at three different values of lattice spacing and two $N_f=2$ ensembles with one pion mass at its physical value and one at 250MeV. The quark disconnected diagrams are computed with sufficient precision by using the stochastic Laplacian Heaviside quark smearing method. For the first time we extrapolate our lattice results to the physical pion mass and continuum limit.
Mr Bartosz Kostrzewa (HISKP (Theory), Universitaet Bonn) Dr Bastian Knippschild (University of Bonn) Christian Jost (University of Bonn) Mr Christopher Helmes (HISKP Universität Bonn) Hang Liu (University of Bern) Dr Konstantin Ottnad (University of Bonn) Dr Marcus Petschlies (University of Bonn) Markus Werner (University of Bonn) Prof. Roberto Frezzotti (University of Rome Tor Vergata, Physics Department and INFN - Sezione di Roma Tor Vergata)