ArcAdiA

Kaon oscillations in the Standard Model and Beyond using Nf=2 dynamical quarks

2011-12-22T13:39:36Z

Kaon oscillations in the Standard Model and Beyond using Nf=2 dynamical quarks Bertone, Valerio; Dimopoulos, Petros; Frezzotti, Roberto; Gimenez, Vicent; Lubicz, Vittorio; Mescia, Federico; Palao, David; Papinutto, Mauro; Rossi, Giancarlo; Simula, Silvano; Vladikas, Anastassios 2009 1-7 We compute non-perturbatively the B-parameters of the complete basis of four-fermion operators needed to study the Kaon oscillations in the SM and in its supersymmetric extension. We perform numerical simulations with two dynamical maximally twisted sea quarks at three values of the lattice spacing on configurations generated by the ETMC. Unwanted operator mixings and O(a) discretization effects are removed by discretizing the valence quarks with a suitable Osterwalder-Seiler variant of the Twisted Mass action. Operators are renormalized non-perturbatively in the RI/MOM scheme. Our preliminary result for BK(RGI) is 0.73(3)(3).

Pseudoscalar decay constants of kaon and D-mesons from Nf=2 twisted mass Lattice QCD

2011-12-22T13:35:27Z

Pseudoscalar decay constants of kaon and D-mesons from Nf=2 twisted mass Lattice QCD 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 2009-07 Journal of High Energy Physics 07 043 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.

Pseudoscalar decay constants of kaon and D-mesons from N-f=2 twisted mass Lattice QCD

2011-12-22T13:35:27Z

Pseudoscalar decay constants of kaon and D-mesons from N-f=2 twisted mass Lattice QCD Blossier, Benoît; Dimopoulos, Pedro; Frezzotti, Roberto; Haas, Benjamin; Herdoiza, Gregorio; Jansen, Karl; Lubicz, Vittorio; Mescia, Federico; Palao, David; Shindler, Andrea; Simula, Silvano; Tarantino, Cecilia; Urbach, Carsten; Wenger, Urs 2009-07 Journal of high energy physics 2009 043 We present the results of a lattice QCD calculation of the pseudoscalar meson decay constants f(pi), f(K), f(D) and f(Ds), performed with N-f =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 similar or equal to 0.10 fm, 0.09 fm and 0.07 fm, with pion masses down to m(pi) similar or equal to 270 MeV. Our results for the light meson decay constants are f(K) =158.1(2.4) MeV and f(K)/f(pi) = 1.210(18). From the latter ratio, by using the experimental determination of Gamma(K -> munu(mu)(gamma))/Gamma(pi -> mu nu(mu)(gamma)) and the average value of vertical bar V-ud vertical bar from nuclear beta decays, we obtain vertical bar V-us vertical bar = 0.2222(34), in good agreement with the determination from semileptonic K-13 decays and the unitarity constraint. For the D and D-s meson decay constants we obtain f(D) =197(9) MeV, f(Ds) = 244(8) MeV and f(Ds)/f(D) = 1.24(3). Our result for f(D) is in good agreement with the CLEO experimental measurement. For f(Ds) our determination is smaller than the PDG 2008 experimental average but in agreement with a recent improved measurement by CLEO at the 1.4 sigma level.