Experimental Study of rho -> pi0 pi0 gamma and omega -> pi0 pi0 gamma Decays

The cross section of the process e+ e- --> omega pi0 --> pi0 pi0 gamma has been measured in the c.m. energy range 920-1380 MeV with the CMD-2 detector. Its energy dependence is well described by the interference of the rho(770) and rho'(1450) mesons decaying to omega pi0. Upper limits for the cross sections of the direct processes e+ e- --> pi0 pi0 gamma, eta pi0 gamma have been set.

The invariant mass spectra of the $\pi^+\pi^-$ and $\pi^\pm\pi^0$ pairs in the process $e^+e^- \to \pi^+\pi^-\pi^0$ were studied in the SND experiment at the VEPP-2M collider in the energy region $\sqrt[]{s} \simeq 1020$ MeV. These studies were based on about $0.5 \times 10^6$ experimental events. The spectra were analyzed in the framework of the vector meson dominance model. It was found that the experimental data can be described with $e^+e^- \to \rho\pi \to \pi^+\pi^-\pi^0...

Using 3.3 pb$^{-1}$ of data collected with the CMD-2 detector in the 720 -- 840 MeV c.m. energy range, the branching fraction of the conversion decay $\omega\to\pi^0e^+e^-$ has been measured: $\mathcal{B}(\omega\to\pi^0e^+e^-)=(8.19\pm0.71\pm0.62)\cdot10^{-4}$. The upper limits for the branching fractions of the following conversion decays have been obtained at the 90% confidence level: $\mathcal{B}(\rho\to\pi^0e^+e^-)<1.6\cdot10^{-5}$, $\mathcal{B}(\rho\to\eta e^+e^-)<0.7\cd...

We present a study of the decays B+ -> rho+ gamma, B0 -> rho0 gamma, and B0 -> omega gamma. The analysis is based on data containing 347 million BBbar events recorded with the BaBar detector at the PEP-II asymmetric B factory. We measure the branching fractions BR(B+ -> rho+ gamma) = (1.10 +0.37/-0.33 +/- 0.09) x 10-6 and BR(B0 -> rho0 gamma) = (0.79 +0.22/-0.20 +/- 0.06) x 10-6, and set a 90% C.L. upper limit BR(B0 -> omega gamma) < 0.78 x 10-6. We also measure the isospin-a...

Upper bound 6*10^{-4} with 90% confidence is reported for the eta -> pi^0 pi^0 decay from the SND experiment at the VEPP-2M collider.

In experiment with the SND detector at VEPP-2M $e^+e^-$ collider the $e^+e^-\to\eta\gamma$ cross section was measured in the energy range $E$=0.60--1.38 GeV with the integrated luminosity of 27.8 pb$^{-1}$. The measured cross section is well described by the vector meson dominance model with contributions from the $\rho(770)$, $\omega(783)$, $\phi(1020)$, $\rho^{\prime}(1465)$ resonances and agrees with results of previous measurements. The decay probabilities $\BR(\phi\to\et...

The reaction e^+e^- ---> OMEGA+PI0 ---> PI+PI- 2PI0 has been studied with SND detector at VEPP-2M e^+e^- collider in the vicinity of the PHI(1020) meson resonance. The observed interference pattern in the energy dependence of the cross section is consistent with existence of the decay PHI ---> OMEGA+PI0 with a branching ratio of B(PHI ---> OMEGA+PI0)=(4.8+1.9-1.7+-0.8)x10^{-5}. The real and imaginary parts of the decay amplitude were measured. The PHI ---> OMEGA+PI0 decay was...

The results of the experimental study of the reactions e+e-->\pi\pi\gamma, \eta\pi\gamma, \eta'\gamma, \omega\pi,... at VEPP-2M collider with CMD-2 and SND detectors are presented. The branching ratios of \phi, \rho, \omega rare decays were measured. The problem of the possible exotic nature of f0(980), a(980) scalar mesons is discussed.

The process $e^+e^-\to\eta\pi^0\gamma$ is studied in the center-of-mass energy range 1.05-2.00 GeV using data with an integrated luminosity of 94.5 pb$^{-1}$ collected by the SND detector at the VEPP-2000 $e^+e^-$ collider. The $e^+e^-\to\eta\pi^0\gamma$ cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the $\omega\eta$ intermediate state. The measured cross section of the subprocess $e^+e^-\to\ome...

A search for the exclusive radiative decays B --> rho(770) gamma and B0 --> omega(782) gamma is performed on a sample of about 84\times 10^{6} B\bar B events collected by the BaBar detector at the PEP-II asymmetric-energy e+e- storage ring. No significant signal is seen in any of the channels. We set upper limits on the branching fractions of BR(B^0 -> rho^0 gamma) < 1.2 \times 10^{-6}, BR(B^+ -> rho^+ gamma) < 2.1 \times 10^{-6}, and BR(B^0 -> omega gamma) < 1.0 \times 10^{-...