相关论文: Precision tests with Kl3 and Kl2 decays

Unitarity along with precision measurements of sin2\beta, V_{us} and V_{cb} allows one to find a lower bound V_{ub}\geq 0.0035 which, on using the recently measured angle \alpha of the unitarity triangle, translates to V_{ub}= 0.0035\pm…

The present status of universality tests of the weak couplings for quarks and leptons is reviewed, with updated information for the muon lifetime and for first-row inputs in the CKM matrix. We discuss the impact of this high-precision SM…

We present a new measurement of the branching ratio R of the decay KL -> pi e nu (Ke3), relative to all charged KL decays with two tracks, based on data taken with the NA48 detector at the CERN SPS. We measure R = 0.4978 +- 0.0035. From…

The leading electromagnetic (e.m.) and strong isospin-breaking corrections to the $\pi^+ \to \mu^+ \nu[\gamma]$ and $K^+ \to \mu^+ \nu[\gamma]$ leptonic decay rates are evaluated for the first time on the lattice. The results are obtained…

We use lattice QCD to fully determine the CKM matrix. |V_{cd}|, |V_{cs}|, |V_{ub}|, |V_{cb}| and |V_{us}| are, respectively, directly determined with recent lattice results for form factors of semileptonic D->pi l nu, D->K l nu, B->pi l nu,…

In this talk I briefly review the precision test of the first row CKM unitarity, focusing mainly on $V_{ud}$ and $V_{us}$ extracted from pion, kaon, neutron and superallowed nuclear beta decays. I will discuss the current status of several…

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…

We perform a detailed, fully-correlated study of the chiral behavior of the pion mass and decay constant, based on 2+1 flavor lattice QCD simulations. These calculations are implemented using tree-level, O(a)-improved Wilson fermions, at…

We present the first quenched lattice QCD study of the form factors relevant for the hyperon semileptonic decay Sigma -> n l nu. The momentum dependence of both axial and vector form factors is investigated and the values of all the form…

I review recent lattice results in kaon physics, particularly in the determination of V_{us} and the B_K parameter of K^0-\bar{K}^0 mixing. I use lattice data to argue for the need of developing SU(2)_L \times SU(2)_R chiral perturbation…

Intriguing results for tests of the universality of electrons and muons through measurements of rates of $B\to K \ell^+ \ell^-$ and similar decays have been in the spotlight for years. The LHCb collaboration has recently reported new…

We review recent measurements of kaon decays and lifetimes for the determination of the CKM element Vus. Their relevance to CKM matrix unitarity is discussed.

In light of ongoing issues with the first-row unitarity test of the CKM matrix, we showcase a global fit to measurements of $K\to \ell \nu$, $K\to \pi\ell \nu$, $\tau \to K\nu$, and $\tau\to K\pi \nu$ decays for the first time. Fitting the…

Using a technique that is not subject to first-order SU(3) symmetry breaking effects, we determine the $V_{us}$ element of the CKM matrix from data on semileptonic hyperon decays. We obtain $V_{us}$ =0.2250(27). This value is of similar…

Recent measurements of the branching fraction for D_s -> l nu disagree with the Standard Model by around 2sigma. In this case the key aspect of the Standard Model is the calculation of the decay constant, f_{D_s}, with lattice QCD. This…

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 detailed numerical study of the K_{e3} decays to O(p^6,(m_d-m_u)p^2,e^2p^2) in chiral perturbation theory with virtual photons and leptons. We describe the extraction of the CKM matrix element |V_{us}| from the experimental…

We present a lattice QCD calculation of the radiative leptonic decay rates of the kaon, improving upon our previous work, arXiv:2006.05358. Our analysis uses gauge ensembles generated by the Extended Twisted Mass Collaboration (ETMC) with…

A calculation of the ratio of leptonic decay constants f_{K^+}/f_{\pi^+} makes possible a precise determination of the ratio of CKM matrix elements |V_{us}|/|V_{ud}| in the Standard Model, and places a stringent constraint on the scale of…

This paper presents the analysis of leptonic and semileptonic kaon decays data done by the FlaviaNet Kaon Working group. Data include all recent results by BNL-E865, KLOE, KTeV, ISTRA+, and NA48. Experimental results are critically reviewed…