http://dspace-roma3.caspur.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 21 May 2013 08:58:55 GMT 2013-05-21T08:58:55Z http://dspace-roma3.caspur.it/image/logo_roma3.jpg http://dspace-roma3.caspur.it:80 http://hdl.handle.net/2307/398 <Title>Pseudoscalar decay constants of kaon and D-mesons from Nf=2 twisted mass Lattice QCD</Title> <Authors>ETM, Collaboration; Blossier, Benoit; Dimopoulos, Petros; Frezzotti, Roberto; Haas, Benjamin; Herdoiza, Gregorio; Jansen, Karl; Lubicz, Vittorio; Mescia, Federico; Palao, David; Shindler, Andrea; Simula, Silvano; Tarantino, Cecilia; Urbach, Carsten</Authors> <Issue Date>2009-07</Issue Date> <Is part of>Journal of High Energy Physics</Is part of> <Volume>07</Volume> <Pages>043</Pages> <Abstract>We present the results of a lattice QCD calculation of the pseudoscalar meson decay constants fπ, fK, fD and fDs, performed with Nf=2 dynamical fermions. The simulation is carried out with the tree-level improved Symanzik gauge action and with the twisted mass fermionic action at maximal twist. We have considered for the final analysis three values of the lattice spacing, a = 0.10 fm, 0.09 fm and 0.07 fm, with pion masses down to mπ = 270 MeV. Our results for the light meson decay constants are fK = 158.1(2.4) MeV and fK/fπ = 1.210(18). From the latter ratio, by using the experimental determination of Γ(K → μbar nuμ(γ))/Γ(π → μbar nuμ(γ)) and the average value of |Vud| from nuclear beta decays, we obtain |Vus| = 0.2222(34), in good agreement with the determination from semileptonic Kl3 decays and the unitarity constraint. For the D and Ds meson decay constants we obtain fD = 197(9) MeV, fDs = 244(8) MeV and fDs/fD = 1.24(3). Our result for fD is in good agreement with the CLEO experimental measurement. For fDs our determination is smaller than the PDG 2008 experimental average but in agreement with a recent improved measurement by CLEO at the 1.4 σ level.</Abstract> Tue, 30 Jun 2009 22:00:00 GMT http://hdl.handle.net/2307/398 2009-06-30T22:00:00Z