Related papers: Improved Standard-Model prediction for $\pi^0\to e…
We suggest to update the expansion coefficients of 2$\pi$DAs with the distribution amplitudes of light mesons evaluated from lattice QCD, with which we revisit $\overline{B}^0 \to \pi^+\pi^0$ transition form factors from light-cone sum…
Based on 7.33 fb$^{-1}$ of $e^+e^-$ collision data taken at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we measure the branching fraction of $D^{*+}_s\to D^+_s\pi^0$ relative to that of $D^{*+}_s\to…
We present a preliminary measurement of the branching fraction for the decay of the neutral $B$ meson into the final state J/$\psi\pi^+\pi^-$. The data set contains approximately 56 million $B\bar{B}$ pairs produced at the $\Upsilon(4S)$…
Employing the standard hard-scattering approach and the running coupling method we calculate a class of power-suppressed corrections $\sim 1/Q^{2n},n=1,2,3,...$ to the electromagnetic $\pi^0\gamma$ transition form factor (FF)…
Using the full data set of the NA48/2 experiment, the decay K+- -> pi+- e+ e- gamma is observed for the first time, selecting 120 candidates with 7.3 +- 1.7 estimated background events. With K+- -> pi+- pi0D as normalisation channel, the…
This letter is the first report of the KL -> pi+- e-+ nu e+ e- decay. Based on 19208+-144 events, we determine the branching fraction, B(KL -> pi+- e-+ nu e+ e-; Mee > 5 MeV/c^2, E*ee > 30 MeV) = (1.285+-0.041)x10^-5, and Gamma(Ke3ee; Mee…
We provide a theoretical update of the calculations of the pi0-gamma*-gamma form factor in the LCSR framework, including up to six polynomials in the conformal expansion of the pion distribution amplitude and taking into account twist-six…
The e+e- -> pi0 pi0 gamma process was studied in the SND experiment at VEPP-2M e+e- collider in the energy region 0.60-0.97 GeV. From the analysis of the energy dependence of measured cross section the branching ratios B(omega -> pi0 pi0…
We demonstrate how a chiral soft pion theorem (SPT) shields the scalar meson ground state isoscalar $\sigma(600-700)$ and isospinor $\kappa(800-900)$ from detection in $a_{1}\to\pi(\pi\pi)_{\mathrm{swave}}$, $\gamma\gamma\to2\pi^{\circ}$,…
Within the hidden local symmetry framework, the Dalitz decay ${\eta}^{\prime}$ ${\to}$ $Ve^{+}e^{-}$ is studied with the vector meson dominance model. It is found that the partial width ${\Gamma}({\eta}^{\prime}{\to}{\omega}e^{+}e^{-})$…
We update our analysis of rho-omega mixing effects in the pion form factor to incorporate the recently published BaBar e^+e^- --> pi^+\pi^- cross-sections. The implications for tau-decay-based Standard Model estimates of the leading order…
The behaviour of the pion transition form factor for the process $\gamma^\star\gamma \to \pi^0$ and $\gamma^\star\gamma^\star\to \pi^0$ at space-like values of photon momenta is estimated within the nonlocal covariant quark-meson model. The…
We present a first study of the scattering process $e^+ e^-\to\pi^+\pi^-\gamma$ beyond next-to-leading order, aimed at providing preliminary insights required for future NNLO predictions for radiative return processes. A complete…
Two aspects of isospin breaking in the decay $K^\pm \to \pi^0 \pi^0 e^\pm \stackrel{_{(-)}}{\nu_e}$ are studied and discussed. The first addresses the possible influence of the phenomenological description of the unitarity cusp on the…
We report an improved measurement of the decay $B^0 \to \pi^0 \pi^0$, using a data sample of 535 $\times 10^6 B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+ e^-$…
After a decade of no measurements of pion and muon rare decays, PIBETA, a new experimental program is producing its first results. We report on a new experimental study of the pion beta decay, Pi(+) -> Pi(0) e(+) Nu, the Pi(e2 gamma)…
We revisit the recently proposed method for the determination of the pi-pi scattering length combination a_{0}-a_{2}, based on the study of the pi0 pi0 spectrum in K+ -> pi+ pi0 pi0. In view of a precision measurement, we discuss here the…
Two pion effective mass and helicity angle distributions in the charged B-meson decays into three charged pions are studied. The weak decay amplitudes are calculated in the framework of the QCD factorization approximation. The strong…
Recent measurement of the $\gamma\gamma^\ast$ form factor of the neutral pion in the high $Q^2$ region disagrees with {\em a priori} predictions of QCD-based calculations. We comment on existing explanations, and analyze a possibility that…
We report the first observation of a number of decay modes of the B meson, namely $B^0 \to D^{*-} (5\pi)^+$, $B^+ \to D^{*-} (4\pi)^{++}$ and $B^+ \to \bar{D}^{*0} (5\pi)^+$, where $(n\pi)$ implies the combination of n charged pions. The…