Related papers: Rare decay $\pi^0\to e^+e^-$: on corrections beyon…

The problem of $\rho$- and $\omega$- mesons contributions to the background for $\eta \to \pi^0 e^+e^-$ decay and to the asymmetries in the decays $\eta \to \pi^+\pi^-\pi^0$ and $\eta \to \pi^+\pi^-\gamma$ is considered.

The $O(\alpha)$ corrections to $\gamma\gamma --> f \bar f$ in the Standard Model are calculated for arbitrary, light fermions $f$. The relevant analytical results are listed in a form that is appropriate for practical applications, and…

The rare decay K_L -> pi pi e e that has recently been observed by KTeV is analyzed in chiral perturbation theory at the one-loop level.

The rare decays $B_s^0\to D^\pm \pi^\mp$ and $\bar B_s^0\to D^\mp \pi^\pm$ can occur only via annihilation type diagrams in the standard model. In this paper, we calculate branching ratios of these decays in perturbative QCD approach…

We calculate the one-loop $Z^0$-penguin contributions to the rare K-decays, $K^+ \to \pi^+ \nu \bar \nu$, $K_L \to \pi^0 \nu \bar \nu$ and $K_L \to \mu^+ \mu^-$, from the unit-charged technipions $\pi_1$ and $\pi_8$ in the framework of the…

The K_S \to pi+/- e+ e- decay mode has been investigated using the data collected in 2002 by the NA48/1 collaboration. With about 23k signal events and 59k K_L \to pi+ pi- pi0_D normalization decays, the K_S \to pi+ pi- e+ e- branching…

The next-to-leading-order electroweak corrections to $pp\to l^+l^-/\bar\nu\nu+\gamma+X$ production, including all off-shell effects of intermediate Z bosons in the complex-mass scheme, are calculated for LHC energies, revealing the…

We report on recent theoretical progress in radiative B decays. We focus on a calculation of logarithmically enhanced QED corrections to the branching ratio and forward-backward asymmetry in the inclusive rare decay anti-B --> X(s) l+ l-,…

A search for the rare decay $B^{+} \to \bar \Lambda p \mu^{+} \mu^{-}$ is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of $\sqrt{s}= 13$ TeV, corresponding to an integrated…

We search for the rare decay $D^+\to D^0 e^+\nu_{e}$, using a data set with an integrated luminosity of 2.93 $\rm fb^{-1}$ collected at $\sqrt{s}=3.773$ GeV with the BESIII detector operating at the BEPCII storage rings. No signals are…

Born cross section and the radiative corrections to its lowest order are considered in the frame work of QED with structureless nucleons including the emission of virtual and real photons. Result is generalized to take into account…

A measurement of the vector to pseudoscalar conversion decay $\phi \to \pi^0 e^+e^-$ with the KLOE experiment is presented. A sample of $\sim 9500$ signal events was selected from a data set of 1.7 fb$^{-1}$ of $e^+e^-$ collisions at…

We report on a search for the decay Kl -> pi0 e+ e- carried out by the KTeV/E799 experiment at Fermilab. This decay is expected to have a significant CP violating contribution and the measurement of its branching ratio could support the CKM…

We calculate the one-photon loop radiative corrections to the charged pion-pair production process $\pi^-\gamma\to\pi^+\pi^-\pi^-$. In the low-energy region this reaction is governed by the chiral pion-pion interaction. The pertinent set of…

The effects of electromagnetic interactions on pseudoscalar decay constants are investigated. Using a compact QED and QCD action we are able to resolve differences of about 0.1 MeV. We obtain the preliminary results f_pi^0-f_pi^+/- =0.09(3)…

We provide a systematic treatment of the previously discovered power-enhanced QED corrections to the leptonic decay $B_q\to \mu^+\mu^-$ ($q = d, s$) in the framework of soft-collinear effective theory (SCET). Employing two-step matching on…

Rare radiative decay $\phi\to\eta\pi^0\gamma$ was studied with SND detector at {VEPP-2M} electron-positron collider and its branching ratio was measured: $B(\phi\to\eta\pi^0\gamma)=(0.88\pm0.14\pm0.09)\cdot 10^{-4}$. Significant…

We calculate the QCD corrections to the cross section of e^+ e^- -> t anti-b H^- and its charge-conjugate counterpart within the minimal supersymmetric extension of the Standard Model. This process is particularly important if m_t < m_H +…

The rare kaon decays $K\to\pi\ell^+\ell^-$ and $K\to\pi\nu\bar{\nu}$ are flavor changing neutral current (FCNC) processes and hence promising channels with which to probe the limits of the standard model and to look for signs of new…

The amplitude of the Dalitz decay pi0 -> e+ e gamma is studied and its model-independent properties are discussed in detail. A calculation of radiative corrections is performed within the framework of two-flavour chiral perturbation theory,…