相关论文: Four Pion Final States with Tagged Photons at Elec…
A Monte Carlo generator has been constructed to simulate the reaction e+ e- --> gamma + 2 pions and gamma + 4 pions, where the photon is assumed to be observed in the detector. Predictions are presented for cms energies of 1GeV, 3GeV and…
We present a sample of results for the cross sections of several processes of low energetic $e^+e^-$ annihilation into final states containing pions accompanied by one or two photons, or a light lepton pair. The results, which have been…
An improved description of four-pion production in electron-positron annihilation and in tau lepton decays is presented. The model amplitude is fitted to recent data from BaBar which cover a wide energy range and which were obtained…
We consider the $\pi^+\pi^-\pi_0\gamma$ final state in electron-positron annihilation at cms energies not far from the threshold. Both initial and final state radiations of the hard photon is considered but without interference between…
The Monte Carlo event generator PHOKHARA, which simulates hadron and muon production at electron-positron colliders through radiative return, has been extended to final states with three pions. A model for the form factor based on…
Electron-positron annihilation into hadrons plus an energetic photon from initial state radiation allows the hadronic cross-section to be measured over a wide range of energies. The full next-to-leading order QED corrections for the…
Final state radiation in the process $e^+e^-\to\pi^+\pi^-$ is considered for the cuts used in the analysis of KLOE data at large angles. By means of a Monte Carlo event generator FEVA, effects of non-pointlike behaviour of pions are…
The process of $e^+ e^-$ annihilation into $\pi^+ \pi^-$ pair with radiation of the photon is considered. The amplitude of the reaction $e^+ e^- \to \pi^+ \pi^- \gamma$ consists of the model independent initial-state radiation (ISR) and…
Contributions from the reaction e+e- --> pi+pi- e+e- to the pion form factor measurement via radiative return method are discussed basing on the results of a Monte Carlo generator (EKHARA). The generator contains contributions from the…
The $\gamma\gamma\to\pi\pi$ reactions are discussed. To describe those processes, we include dipion continuum, resonances, high-energy pion-pion rescatterings, $\rho$ meson exchange and pQCD Brodsky-Lepage mechanisms. The cross section for…
A fully massive Monte Carlo program to compute all four-fermion processes in electron positron collisions, including Higgs boson production, is presented. Leading higher order effects are discussed and included.
We consider the process of annihilation of e^+ e^- to three pion final state for the case of moderately high energies. The final state emission of virtual and real photon is considered explicitly. The calculations are performed in frames of…
The processes of muons (tau) and charged pions pairs production at electron-positron annihilation with first order radiative corrections are considered. The calculation results are presented assuming the energies of final particles (cms…
Processes of electron-positron annihilation into charged pions and kaons are considered. Radiative corrections are taken into account exactly in the first order and within the leading logarithmic approximation in higher orders. A combined…
The process of $e^+e^-$ annihilation into a $\pi^+\pi^-$ pair with radiation of a photon is considered. The amplitude of the reaction $e^+e^-\to\pi^+\pi^-\gamma$ consists of the model independent initial-state radiation (ISR) and…
In this paper a Monte Carlo generator, GaGaRes, is presented which can be used to describe two-photon resonance production in e^+e^- collisions. The program can generate the five lowest-lying C=+1 meson states of any q\bar{q} combination…
The production of four fermions plus a visible photon in electron-positron collisions is analyzed, with particular emphasis on the LEP2 energy range. The study is based on the calculation of exact matrix elements, including the effect of…
Recently, various cross sections of e+e- annihilation into hadrons were accurately measured in the energy range from 0.37 to 1.39 GeV with the CMD-2 detector at the VEPP-2M collider. In the pi+pi- channel a systematic uncertainty of 0.6%…
We compute the radiative corrections to the process of two-pion production in association with a hard photon in $e^+ e^-$ annihilation by taking into account the non-perturbative structure of the pion in the one-loop calculation. For this…
Effects due to non-pointlike behaviour of pions in the process $e^+e^-\to\pi^+\pi^-\gamma$ can arise for hard photons in the final state. By means of a Monte Carlo event generator, which also includes the contribution of the direct decay…