ArcAdiAThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.http://dspace-roma3.caspur.it:802015-01-31T08:36:37Z2015-01-31T08:36:37ZKaon oscillations in the Standard Model and Beyond using Nf=2 dynamical quarksBertone, ValerioDimopoulos, PetrosFrezzotti, RobertoGimenez, VicentLubicz, VittorioMescia, FedericoPalao, DavidPapinutto, MauroRossi, GiancarloSimula, SilvanoVladikas, Anastassioshttp://hdl.handle.net/2307/3102011-12-22T13:39:36Z2008-12-31T23:00:00Z<Title>Kaon oscillations in the Standard Model and Beyond using Nf=2 dynamical quarks</Title>
<Authors>Bertone, Valerio; Dimopoulos, Petros; Frezzotti, Roberto; Gimenez, Vicent; Lubicz, Vittorio; Mescia, Federico; Palao, David; Papinutto, Mauro; Rossi, Giancarlo; Simula, Silvano; Vladikas, Anastassios</Authors>
<Issue Date>2009</Issue Date>
<Pages>1-7</Pages>
<Abstract>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).</Abstract>2008-12-31T23:00:00ZVector and scalar form factors for K- and D-mesonsemileptonic decays from twisted mass fermionswith Nf = 2Di Vita, StefanoHaas, BenjaminLubicz, VittorioMescia, FedericoSimula, SilvanoTarantino, Ceciliahttp://hdl.handle.net/2307/2712011-12-22T13:39:36Z2008-12-31T23:00:00Z<Title>Vector and scalar form factors for K- and D-mesonsemileptonic decays from twisted mass fermionswith Nf = 2</Title>
<Authors>Di Vita, Stefano; Haas, Benjamin; Lubicz, Vittorio; Mescia, Federico; Simula, Silvano; Tarantino, Cecilia</Authors>
<Issue Date>2009</Issue Date>
<Pages>257-264</Pages>
<Abstract>We present lattice results for the formfactors relevant in the K→p ℓnℓ and D→p ℓnℓ semileptonic
decays, obtained from simulations with two flavors of dynamical twisted-mass fermions and pion
masses as light as 260 MeV. For K →p ℓn decays we discuss the estimates of the main sources
of systematic uncertainties, including the quenching of the strange quark, leading to our final result
f+(0) = 0.9560(57)stat.(62)syst.. Combined with the latest experimental data, our value of
f+(0) implies for the CKMmatrix element |Vus| the value 0.2267(5)exp.(20) f+(0) consistent with
the first-row CKM unitarity. For D →p ℓnℓ decays the application of Heavy Meson Chiral Perturbation
Theory allows to extrapolate our results for both the scalar and the vector form factors
at the physical point with quite good accuracy, obtaining a nice agreement with the experimental
data. In particular at zero-momentumtransfer we obtain f+(0) = 0.64(5). A preliminary analysis
of the discretization effects is presented and discussed.</Abstract>2008-12-31T23:00:00ZK ->pi l nu semileptonic form factors from two-flavor lattice QCDLubicz, VittorioMescia, FedericoSimula, SilvanoTarantino, Ceciliahttp://hdl.handle.net/2307/3152011-12-22T13:35:27Z2009-11-30T23:00:00Z<Title>K ->pi l nu semileptonic form factors from two-flavor lattice QCD</Title>
<Authors>Lubicz, Vittorio; Mescia, Federico; Simula, Silvano; Tarantino, Cecilia</Authors>
<Issue Date>2009-12</Issue Date>
<Is part of>Physical review D</Is part of>
<Volume>80</Volume>
<Pages>111502</Pages>
<Abstract>We present new lattice results of the K ->pi l nu semileptonic formfactors obtained from simulations with two flavors of dynamicaltwisted-mass fermions, using pion masses as light as 260 MeV. Our mainresult is f(+)(0)=0.9560(84), which, combined with the latestexperimental data for K-l3 decays, leads to|V-us|=0.2267(5)(exp)(20)(f+)(0). Using the PDG(2008) determinations of|V-ud| and |V-ub| our result implies for the unitarity relation|V-ud|(2)+|V-us|(2)+|V-ub|(2)=1.0004(15). For the O(p(6)) term of thechiral expansion of f(+)(0) we get Delta f equivalent tof(+)(0)-1-f(2)=-0.0214(84).</Abstract>2009-11-30T23:00:00ZAn estimate of the B --> K* γ Decay Form FactorBecirevic, DamirLubicz, VittorioMescia, Federicohttp://hdl.handle.net/2307/2372011-12-22T13:35:27Z2007-03-31T22:00:00Z<Title>An estimate of the B --> K* γ Decay Form Factor</Title>
<Authors>Becirevic, Damir; Lubicz, Vittorio; Mescia, Federico</Authors>
<Issue Date>2007-04</Issue Date>
<Is part of>Nuclear Physics B</Is part of>
<Volume>769</Volume>
<Pages>31-43</Pages>
<Abstract>We present the results of a lattice QCD calculation of the form factor relevant to B→K*γ decay. Our final value, T(0) = 0.24 +/- 0.03 (+0.04/-0.01), is obtained in the quenched approximation, and by extrapolating T(q2=0;H--> K*)MH^(3/2) from the directly accessed H-heavy mesons to the meson B. We also show that the extrapolation from B→K*γ* (q2≠0) to B→K*γ (q2=0), leads to a result consistent with the one quoted above. On the other hand, our results are not accurate enough to solve the SU(3) flavor breaking effects in the form factor and we quote TB→K*(0)/TB→ρ(0)=1.2(1), as our best estimate.</Abstract>2007-03-31T22:00:00ZK ->pi l nu semileptonic form factors from two-flavor lattice QCDLubicz, VittorioMescia, FedericoSimula, SilvanoTarantino, Ceciliahttp://hdl.handle.net/2307/3612011-12-22T13:35:27Z2009-12-29T23:00:00Z<Title>K ->pi l nu semileptonic form factors from two-flavor lattice QCD</Title>
<Authors>Lubicz, Vittorio; Mescia, Federico; Simula, Silvano; Tarantino, Cecilia</Authors>
<Issue Date>2009-12-30</Issue Date>
<Is part of>Physical Review D</Is part of>
<Volume>80</Volume>
<Pages>111502</Pages>
<Abstract>We present new lattice results of the K ->pi l nu semileptonic form factors obtained from simulations with two flavors of dynamicaltwisted-mass fermions, using pion masses as light as 260 MeV. Our main result is f(+)(0)=0.9560(84), which, combined with the latest experimental data for Kl3 decays, leads to |Vus|=0.2267(5)(exp)(20)(f+(0)). Using the PDG(2008) determinations of|Vud| and |Vub| our result implies for the unitarity relation |Vud|^2+|Vus|^2+|Vub|^2=1.0004(15). For the O(p^6) term of the chiral expansion of f+(0) we get Delta f = f+(0)-1-f2=-0.0214(84).</Abstract>2009-12-29T23:00:00ZPseudoscalar decay constants of kaon and D-mesons from Nf=2 twisted mass Lattice QCDETM, CollaborationBlossier, BenoitDimopoulos, PetrosFrezzotti, RobertoHaas, BenjaminHerdoiza, GregorioJansen, KarlLubicz, VittorioMescia, FedericoPalao, DavidShindler, AndreaSimula, SilvanoTarantino, CeciliaUrbach, Carstenhttp://hdl.handle.net/2307/3982011-12-22T13:35:27Z2009-06-30T22:00:00Z<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>2009-06-30T22:00:00ZPseudoscalar decay constants of kaon and D-mesons from N-f=2 twisted mass Lattice QCDBlossier, BenoîtDimopoulos, PedroFrezzotti, RobertoHaas, BenjaminHerdoiza, GregorioJansen, KarlLubicz, VittorioMescia, FedericoPalao, DavidShindler, AndreaSimula, SilvanoTarantino, CeciliaUrbach, CarstenWenger, Urshttp://hdl.handle.net/2307/5262013-09-25T15:14:26Z2009-06-30T22:00:00Z<Title>Pseudoscalar decay constants of kaon and D-mesons from N-f=2 twisted mass Lattice QCD</Title>
<Authors>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</Authors>
<Issue Date>2009-07</Issue Date>
<Is part of>Journal of high energy physics</Is part of>
<Volume>2009</Volume>
<Pages>043</Pages>
<Abstract>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.</Abstract>2009-06-30T22:00:00Z