相关论文: Long-distance contributions to flavour-changing pr…
Kaon flavour physics has played in the 1960s and 1970s a very important role in the construction of the Standard Model (SM) and in the 1980s and 1990s in SM tests with the help of CP violation in $K_L\to\pi\pi$ decays represented by…
In this short presentation I emphasize the increased importance of kaon flavour physics in the search for new physics (NP) that we should witness in the rest of this decade and in the next decade. The main actors will be the branching…
In this contribution, we present recent progress from the RBC/UKQCD collaboration on the first calculation of the long-distance two-photon contribution to the decay amplitude of a long-lived kaon into a pair of charged muons.
A number of old and new methods for computing $K\to\pi\pi$ amplitudes on the lattice are reevaluated. They all involve a non-perturbative determination of matching coefficients. I will show how problems related to operator mixing can be…
We present a lattice-QCD calculation of the long-distance two-photon contribution to the decay amplitude of a long-lived kaon to a pair of muons on a $24^3\times 64$ physical-pion-mass ensemble. In these proceedings, the theoretical…
I present a selection of recent lattice results in flavourdynamics, including the status of the calculation of quark masses and a variety of weak matrix elements relevant for the determination of CKM matrix elements. Recent improvements in…
We have completed a lattice QCD calculation of $\Delta m_K$, the mass difference between the long- and short-lived K mesons. The calculation was performed on a $64^3 \times 128$ lattice using 152 configurations with physical quark masses…
We calculate the long distance contribution to $D^{+,0}\to\pi^{+,0}l^+l^-$ decays by the use of a vector meson dominance model, in which the $\phi$-meson plays the central role. The branching ratios obtained are $10^{-6}$ and a few times…
We investigate rare semileptonic $B \to K^\ast\ell^+\ell^-$ by looking at the long distance contributions. Our analysis is limited to the very small values of physical accessible range of invariant mass of the leptonic couple $q^2$. We show…
I review lattice calculations of quantities that involve light quarks, including light quark masses, the vector form factor f_+(0) needed for semileptonic kaon decays, and kaon mixing. Results for most of these quantities are now available…
The electromagnetic contribution to the $K^+ - K^0$ mass difference is calculated in the $1/N_c$ approach including the $SU(3)$ breaking contributions due to a non-zero strange quark mass. The short-distance contribution can be…
An amplitude analysis of the $B^0 \to K^{*0} \mu^+\mu^-$ decay is presented. The analysis is based on data collected by the LHCb experiment from proton-proton collisions at $\sqrt{s} = 7,\,8$ and $13$ TeV, corresponding to an integrated…
Long-distance effects in exclusive rare semileptonic transitions B -> (K, K*) are analysed within a relativistic quark model. The meson transition form factors, describing the meson amplitudes of the effective weak Hamiltonian, are…
Rare $K \to \pi \nu \bar \nu$ decays, being dominated by short distance contributions within the Standard Model (SM), open a window for New Physics (NP) searches at low energies. The $ K \to \pi \nu \bar\nu $ branching ratios are expected…
We review recent results of Lattice QCD calculations relevant for flavour physics. We discuss in particular the hadronic parameters entering the amplitudes of K0-K0bar, D0-D0bar and B0-B0bar mixing, the B- and D-meson decay constants and…
Leptonic and semileptonic kaon decays represent till now the golden modes for the extraction of the Cabibbo angle from experiments, provided the relevant hadronic quantities, namely the ratio of the kaon and pion leptonic decay constants,…
We have identified a missing long-distance (one-photon exchange) contribution to the $B^\pm\to K^\pm/\pi^\pm\ell^+\ell^-$ decays. Although it does not help to explain the anomaly measured by the LHCb Coll. in the ratio $R_K =…
Hadronic contributions dominate the uncertainty of the standard model prediction for the anomalous magnetic moment of the muon. In this work, we describe an ongoing lattice calculation of the hadronic light-by-light contribution, performed…
The impact of rare lepton decays ($\mu \to e \gamma$, $\tau \to \mu \gamma$, >...) and rare $B$ and $K$ decays ($B\to \ell^+\ell^-$, $B\to \ell\nu$, $K\to \pi \nu\nu$, $K\to\ell\nu$, ...) in probing the existence of an underlying flavour…
We review some recent theoretical results on rare kaon decays. Particular attention is devoted to establish the short distance (direct CP violating) contribution to K_L => \pi^0 e \bar{e}. This is achieved by a careful study of the long…