The process e+e−→ωπ0→π0π0γ up to 1.4 GeV

Physical Review D, 2013

Study of e + e − → ωπ 0 → π 0 π 0 γ in the energy range 1.05-2.00 GeV with SND The cross section for the process e + e − → ωπ 0 → π 0 π 0 γ has been measured in the center-of-mass energy range 1.05-2.00 GeV. The experiment has been performed at the e + e − collider VEPP-2000 with the SND detector. The measured e + e − → ωπ 0 cross section above 1.4 GeV is the most accurate to date. Below 1.4 GeV our data are in good agreement with the previous SND and CMD-2 measurements. Data on the e + e − → ωπ 0 cross section are well described by the Vector Meson Dominance (VMD) model with two excited ρ-like states. From the measured cross section we have extracted the γ * → ωπ 0 transition form factor. It has been found that the VMD model cannot describe simultaneously our data and data obtained from the ω → π 0 µ + µ − decay. We have also tested Conserved Vector Current (CVC) hypothesis comparing our results on the e + e − → ωπ 0 cross section with data on the τ − → ωπ − ντ decay and have found that the CVC hypothesis works well within reached experimental accuracy of about 5%.

Physics Letters B, 1999

The process e + e − → π + π − π 0 in the energy range 2E 0 = 1.04-1.38 GeV

EPJ Web of Conferences

Existing Monte-Carlo generators with radiative corrections to the e+e-→π+π- process are usually developed under the assumption that pions can be treated as pointlike particles. We study the e+e-→π+π-γ process with final-state radiation and test this assumption using simulated events from the MCGPJ generator based on the scalar QED hypothesis. In order to increase a fraction of events with FSR, the analysis was performed in the energy region to the left from the ρ-meson peak (660÷785 MeV) that is based on the integrated luminosity of about 8.4 pb-1. The experimental data for the photon energy spectrum agree with the simulation results at 1% level.

Physical Review D, 2015

In the experiment with the SND detector at the VEPP-2000 e + e − collider the cross section for the process e + e − → ηπ + π − has been measured in the center-of-mass energy range from 1.22 to 2.00 GeV. Obtained results are in agreement with previous measurements and have better accuracy. The energy dependence of the e + e − → ηπ + π − cross section has been fitted with the vector-meson dominance model. From this fit the product of the branching fractions B(ρ(1450) → ηπ + π − )B(ρ(1450) → e + e − ) has been extracted and compared with the same products for ρ(1450) → ωπ 0 and ρ(1450) → π + π − decays. The obtained cross section data have been also used to test the CVC hypothesis.

Physical Review D

We analyze a 37 pb −1 data sample collected with the SND detector at the VEPP-2000 e + e − collider in the center-of-mass energy range 1.05-2.00 GeV and present an updated measurement of the e + e − → ωπ 0 → π 0 π 0 γ cross section. In particular, we correct the mistake in radiative correction calculation made in our previous measurement based on a part of the data. The measured cross section is fitted with the vector meson dominance model with three ρ-like states and used to test the conserved vector current hypothesis in the τ − → ωπ − ντ decay.

Physics Letters B, 2004

The e + e − → π + π − π + π − cross section has been measured using 5.8 pb −1 of integrated luminosity collected with the CMD-2 detector at the VEPP-2M collider. Analysis of the data with a refined efficiency determination and use of both threeand four-track events allowed doubling of a data sample and reduction of systematic errors to 5-7%.

Physics Letters B, 1986

The reaction e+e -~ cmr ° ~ 7r0~r°y has been studied with the Neutral Detector at the VEPP-2M coUider. The cross section values differ from the predictions of the vector dominance model with one p(770) meson, and are consistent with the contributions of p(770) and p(1600). O(1250) has not been observed.

International Journal of Modern Physics: Conference Series, 2014

We report preliminary results on the measurement of the cross section of the process e+e- → K+K-π+π- in the c.m. energy range from 1.5 GeV to 2 GeV. It is shown that the cross section is dominated by the contributions of several intermediate states K+K-ρ, K*Kπ, ϕπ+π- and K*K*.

2010

In an experiment with the Spherical Neutral Detector at VEPP-2M collider the cross section of the process e+e- → π+π-π0π0 was measured. At energies √s < 920 MeV this cross section was measured for the first time. The energy dependence of the cross section is well discribed by the vector dominance model with contributions from ρ, ρ', ρ'' mesons. The decay probability ρ → π +π-π0π0 was found to be Bρ = (1.60±0.74±0.18) × 10-5. The upper limit for the decay ω → π+π-π0π0 was improved by two orders of magnitude compared to the previous measurements and is Bω < 2 × 10-4 at 90% confidence level.

Physical Review D, 2014

The e + e − → ηγ cross section has been measured in the center-of-mass energy range 1.07-2.00 GeV using the decay mode η → 3π 0 , π 0 → γγ. The analysis is based on 36 pb −1 of integrated luminosity collected with the SND detector at the VEPP-2000 e + e − collider. The measured cross section of about 35 pb at 1.5 GeV is explained by decays of the ρ(1450) and φ(1680) resonances.