First results of ETMC simulations with Nf=2+1+1 maximally twisted mass fermions

8 pages, 4 figures. Talk presented at the XXVII International Symposium on Lattice Field Theory, July 26-31 2009, Peking University, Beijing, ChinaInternational audienceWe present first results from runs performed with Nf=2+1+1 flavours of dynamical twisted mass fermions at maximal twist: a degenerate light doublet and a mass split heavy doublet. An overview of the input parameters and tuning status of our ensembles is given, together with a comparison with results obtained with Nf=2 flavours. The problem of extracting the mass of the K- and D-mesons is discussed, and the tuning of the strange and charm quark masses examined. Finally we compare two methods of extracting the lattice spacings to check the consistency of our data and we present some first results of ChiPT fits in the light meson sector