Related papers: Vus from Kl3 Decays
Semileptonic $D \to{}K \ell \nu$ decays provide one angle of attack to get at the CKM matrix element $V_{cs}$, complementary to the study of leptonic $D_s$ decays. Here, HPQCD present the results of a recently published, improved…
The most recent determinations of $V_{ud}$ from superallowed beta decays lead to a discrepancy when compared to the value implied by mesonic CKM measurements combined with CKM unitarity. On top of this, improved precision in lattice QCD…
The recent update of the strange spectral function and the moments of the invariant mass distribution by the OPAL collaboration from hadronic tau decay data are employed to determine |V_us| as well as m_s. Our result,…
We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V_{cb}| and of the parameters rho^2, R_1(1), and R_2(1), which fully characterize the form factors for the B0 -> D*- l+ nu_l decay in the framework of…
We calculate the form factor f_+(q^2) for B-meson semileptonic decay in unquenched lattice QCD with 2+1 flavors of light sea quarks. We use Asqtad-improved staggered light quarks and a Fermilab bottom quark on gauge configurations generated…
We summarize recent b -> s mu mu results from the CDF experiment based on the full 9.6 fb-1 dataset collected in p-pbar collisions at sqrt(s) = 1.96 TeV. The decays analyzed are; B+ -> K+ mu+ mu-, B0 -> K*0(892) mu+ mu-, B0 -> K0_s mu+ mu-,…
The current value of Vud is determined from superallowed beta-decay experiments. Other methods, briefly summarised here, have to overcome specific experimental hurdles before they are competitive. However, the nuclear results do depend on a…
By analyzing all existing measurements for $ D\rightarrow K \ell^+ \nu_{\ell} $ ( $\ell=e,\ \mu$ ) decays, we find that the determinations of both the vector form factor $f_+^K(q^2)$ and scalar form factor $f_0^K(q^2)$ for semileptonic…
We present results of a lattice computation of the vector and axial-vector current matrix elements relevant for the semileptonic decay B^0-bar -> rho^+ l^- nu_l-bar. The computations are performed in the quenched approximation of lattice…
Measurements of many Standard Model constants are clouded by uncertainties in nonperturbative QCD parameters that relate measurable quantities to the underlying parton-level processes. Generally these QCD parameters have been obtained from…
Semileptonic $B_s \to K \ell \nu$ decays provide an alternative $b$-decay channel to determine the CKM matrix element $|V_{ub}|$, and to obtain a $R$-ratio to investigate lepton-flavor-universality violations. Results for the CKM matrix…
Short description of our calculation of the form factor needed to determine CKM element |V_{cb}| from the exclusive decay B -> D^*l\nu. For full details, see hep-ph/0110253. Also, here we recommend distribution for CKM fits.
The determination of $|V_{us}|$ from kaon semileptonic decays requires the value of the form factor $f_+(q^2=0)$ which can be calculated precisely on the lattice. We provide the one-loop partially quenched chiral perturbation theory…
The element Vub of the CKM mixing matrix is the smallest of the quark couplings and is crucial in understanding CP violation in the B system. In this review, we discuss the present status of the determination of its magnitude, which…
We present new lattice results of the K -> pion semileptonic form factors obtained from simulations with two flavors of dynamical twisted-mass fermions, using pion masses as light as 260 MeV. Our main result is f+(0) = 0.9560 (84), which,…
We calculate the kaon semileptonic form factor $f_+(0)$ from lattice QCD, working, for the first time, at the physical light-quark masses. We use gauge configurations generated by the MILC collaboration with $N_f=2+1+1$ flavors of sea…
Recent analyses of the LEP and Upsilon(4S) data have better outlined the picture of semileptonic B decays. Results on inclusive and exclusive decay branching fractions and on the extraction of the |Vub| and |Vcb| elements of the CKM mixing…
We present the first measurement of the form factor ratios g1/f1 (direct axial-vector to vector), g2/f1 (second class current) and f2/f1 (weak magnetism) for the decay Xi0 -> Sigma+ e- anti-nu/e using the KTeV (E799) beam line and detector…
We discuss the reduction of errors in the calculation of the form factor $f_+^{K \pi}(0)$ with HISQ fermions on the $N_f=2+1+1$ MILC configurations from increased statistics on some key ensembles, new data on ensembles with lattice spacings…
Already in the past, hadronic tau decays have served as an interesting source to obtain information on the parameters of the Standard Model, like the strong coupling alpha_s or the strange quark mass. Below it will be shown that the…