Related papers: Pion Beta Decay and CKM Unitarity
After the recent high precision determinations of $V_{us}$ and $V_{ud}$, the first row of the CKM matrix shows more than $4\sigma$ deviation from unitarity. Two possible scenarios beyond the Standard Model can be investigated in order to…
The decays $B^\pm\to \pi^\pm K$ and $B_d\to \pi^\mp K^\pm$ were observed by the CLEO collaboration last year; they may play an important role to probe the angle $\gamma$ of the unitarity triangle of the CKM matrix. After a general…
With the recent measurements of purely leptonic $D^+_{(s)}$ decays and semileptonic $D$ decays in conjunction with decay constants $f_{D^+_{(s)}}$ and form factors $f^{\pi(K)}_+(0)$ calculated in LQCD, we extract the magnitudes of $V_{cd}$…
Within the framework of chiral perturbation theory with virtual photons and leptons, we present an updated analysis of the pionic beta decay including all electromagnetic contributions of order e**2 p**2. We discuss the extraction of the…
The decays $B_d\to \pi^+ \pi^-$ and $B_s\to K^+ K^-$ are related to each other by interchanging all down and strange quarks, i.e. through the $U$-spin flavour symmetry of strong interactions. A completely general parametrization of the…
By globally analyzing all existing measured branching fractions for $D\to \pi e^+\nu_e$ decays, partial decay rates in different four momentum transfer-squared $q^2$ bins, as well as products of the decay form factor $f_+^\pi(q^2)$ and the…
We have searched for the K+ to pi+ gamma gamma decay in the kinematic region with pi+ momentum close to the end point. No events were observed, and the 90% confidence-level upper limit on the partial branching ratio was obtained, B(K+ to…
The electromagnetic structure of the nucleon can be determined from the scattering of electrons off a nucleon target. However, to study its axial structure, neutrino beams are required. The results from these experiments should be…
In an analysis of a 2.92~fb$^{-1}$ data sample taken at 3.773~GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions to be $\mathcal B(D^0 \to K^-e^+\nu_e)=(3.505\pm 0.014 \pm…
A major goal in B physics is measuring the CP-violating asymmetry in the decay $B^0 \rightarrow \pi^+ \pi^-$. In order to determine one of the phase angles in the CKM matrix from this decay it is necessary to determine the influence of the…
We present the results of a lattice computation of the form factors for B^0 ->pi^- l^+nu_l decays near zero-recoil. These results will allow a determination of the CKM matrix element |Vub| when measurements of the differential decay rate…
We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle physics community. More specifically, we report on the determination of the light-quark masses, the form…
Measurements of the rates for the hadronic decays B^+- -> pi K along with the CP-averaged B^+- -> pi^+- pi^0 branching ratio can be used to bound and extract the weak phase gamma=-arg(V_ub). Using preliminary CLEO data, we obtain the bounds…
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…
We present a lattice determination of the vector and scalar form factors of the $D \to \pi(K) \ell \nu$ semileptonic decays, which are relevant for the extraction of the CKM matrix elements $|V_{cd}|$ and $|V_{cs}|$ from experimental data.…
We propose two independent methods to determine the CKM phase $\gamma$ and the tree and penguin amplitudes using neutral $B$ decays, assuming that the phase $\beta$ is known. Based on flavor SU(3) symmetry and SU(3) breaking effect, one…
The interference between Cabibbo-favoured and Cabibbo-suppressed $B\to D\pi$ decay amplitudes provides sensitivity to the CKM angle $\gamma$. The relative size of the interfering amplitudes is an important ingredient in the determination of…
The Vud element of the Cabibbo-Kobayashi-Maskawa matrix can be determined from several different experimental approaches: either 0+-to-0+ superallowed nuclear beta decays, neutron decay, nuclear mirror decays, or pion beta decay. Currently…
Neutrinoless double beta decay, if detected, would prove that neutrinos are Majorana fermions and provide the direct evidence for lepton number violation. If such decay would exist in nature, then $\pi^-\pi^-\to ee$ and $\pi^-\to\pi^+ ee$…
We point out that the recently increased value of the angle $\gamma$ in the Unitarity Triangle (UT), determined in tree-level decays to be $\gamma=(74.0^{+5.0}_{-5.8})^\circ$ by the LHCb collaboration, combined with the most recent value of…