Duality violations in hadronic tau decays and the value of alpha_s
  We discuss the quantitative impact of duality violations on the determination of the strong coupling constant from hadronic tau decays, based on a preliminary analysis of OPAL data. 
Diogo Boito, Oscar Cata, Maarten Golterman, Matthias Jamin, Kim   Maltman, James Osborne, Santiago Peris
hep-ph hep-ex hep-lat