Related papers: Processes $e^+e^-\to\pi^0({\pi^0}')\gamma$ in 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…
The $e^+e^-\to\eta\gamma$ cross section has been measured in the center-of-mass energy range 1.07--2.00 GeV using the decay mode $\eta\to 3\pi^0$, $\pi^0\to \gamma\gamma$. The analysis is based on 36 pb$^{-1}$ of integrated luminosity…
The electron positron annihilation reaction into four pion production has been studied, through the channel $e^++e^-\to \bar \rho+\rho $. The differential (and total) cross sections and various polarization observables for this reaction…
We study the processes $e^+ e^- \to \ \gamma_{\rm ISR} J/\psi$ where $J/\psi \to \pi^+ \pi^- \pi^0$, $J/\psi \to K^+ K^- \pi^0$, and $J/\psi \to K^0_S K^{\pm} \pi^{\mp}$ using a data sample of 519 $fb^{-1}$ recorded with the BaBar detector…
We consider the electron-positron annihilation process into hadrons $R_{e^+e^-}$ up to $\mathcal{O}(\alpha_{s}^{3})$ and we adopt the smearing method suggest by Poggio, Quinn and Weinberg to confront the experimental data with theory. As a…
The $\gamma n \to \pi^- p$ and $\gamma p \to \pi^+ n$ reactions are essential probes of the transition from meson-nucleon degrees of freedom to quark-gluon degrees of freedom in exclusive processes. The cross sections of these processes are…
In this paper initial state radiation corrections to double production of charmonium mesons on one-photon electron-positron annihilation at center of mass energy $\sqrt{s}=10.6\GeV$ are studied. It is shown, that these corrections have…
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…
Exclusive electroproduction of pi0 mesons on protons in the backward hemisphere has been studied at Q**2 = 1.0 GeV**2 by detecting protons in the forward direction in coincidence with scattered electrons from the 4 GeV electron beam in…
It is shown that an account for the final-state interaction of real or virtual nucleon and antinucleon produced in the processes $J/\psi\to p\bar{p}\gamma$, $\psi(2S)\to p\bar{p}\gamma$, $J/\psi\to p\bar{p}\omega$, and…
Observations of annihilation radiation in the Galaxy are briefly reviewed. We summarize astrophysical mechanisms leading to positron production, and recent estimates for production rates from nova and supernova nucleosynthesis in the…
We study the processes $e^+e^-\to 2(\pi^+\pi^-)\pi^0\pi^0\pi^0\gamma$ and $2(\pi^+\pi^-)\pi^0\pi^0\eta\gamma$ in which an energetic photon is radiated from the initial state. The data were collected with the \babar~ detector at SLAC. About…
We present a theoretical study of the $\gamma\gamma \to \pi\eta$ process from the threshold up to 1.4 GeV in the $\pi\eta$ invariant mass. For the s-wave $a_0(980)$ resonance state we adopt a dispersive formalism using a coupled-channel…
The process $e^+e^- \to K^0_L K^0_S$ has been studied with the CMD-2 detector using about 950 events detected in the center-of-mass energy range from 1.05 to 1.38 GeV. The cross section exceeds the expectation based on the contributions of…
Based on 22.7 fb$^{-1}$ of $e^+e^-$ annihilation data collected at 33 different center-of-mass energies between 3.7730 GeV and 4.7008 GeV with the BESIII detector at the BEPCII collider, Born cross sections of the two processes $e^+e^-\to…
Radiative corrections due to pair production in process of electron-positron annihilation are considered. The main attention is paid to the corrections of the third order. Simultaneous emission of photons and pairs is taken into account.…
We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) >~ sigma(e+e- --> pbar p). We discuss an interpretation in terms of…
The process of electron--positron annihilation into proton--antiproton pair is considered within the vicinity of $\psi(3770)$ resonance. The interference between the pure electromagnetic intermediate state and the $\psi(3770)$ state is…
We use a boost-invariant one-dimensional (cylindrically symmetric) fluid dynamics code to calculate $e^+e^-$ production from $\rho^0$ and $\omega$ decay in the central rapidity region of a central S+Au collision at $\sqrt{s}=20$…
Born differential cross sections and the lowest-order radiative correction to them are obtained in the kinematics of large-angle final photons emission in high-energy electron-positron annihilation processes. Taking into account possible…