Impact of dynamical charm quarks
  We compute and compare the continuum limits of several quantities in QCD with and without a dynamical charm quark. We consider both low energy quantities, like the hadronic scales $r_0$ and $t_0$, and high energy quantities, like the charmonium masses. 
Tomasz Korzec, Francesco Knechtli, Salvatore Cali, Bjorn Leder, Graham   Moir
hep-lat