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.
Measurement of the Born cross section and the 'Bare' cross section of the process E+ E- --> OMEGA < PI0 GAMMA > PI0.
We measured the inclusive electron-proton cross section in the nucleon resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2 with the CLAS detector. The large acceptance of CLAS allowed for the first time the measurement of the cross section in a large, contiguous two-dimensional range of Q**2 and x, making it possible to perform an integration of the data at fixed Q**2 over the whole significant x-interval. From these data we extracted the structure function F2 and, by including other world data, we studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate higher twist contributions. The small statistical and systematic uncertainties of the CLAS data allow a precise extraction of the higher twists and demand significant improvements in theoretical predictions for a meaningful comparison with new experimental results.
No description provided.
No description provided.
No description provided.
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 the rho(770), omega(782) and phi(1020) mesons only.
Measured cross section and 'bare' cross section for the process E+ E- --> KL KS.
First results of the study of the process e+e- \to 4\pi by the CMD-2 collaboration at VEPP-2M are presented for the energy range 1.05--1.38 GeV. Using an integrated luminosity of 5.8 pb^{-1}, energy dependence of the processes e+e- \to \pi^+\pi^- 2\pi^0 and e+e- \to 2\pi^+ 2\pi^- has been measured. Analysis of the differential distributions demonstrates the dominance of the a_1\pi and \omega\pi intermediate states. Upper limits for the contributions of other alternative mechanisms are also placed.
Energy dependence of the cross section for the 2PI+ 2PI- final state. Statistical errors only.
Energy dependence of the cross section for the PI+ PI- 2PI0 final state. Statistical errors only.
Energy dependence of the cross section for the OMEGA PI0 final state. Statistical errors only.
We report measurements of the asymmetry A_parallel for inclusive hadron production on longitudinally polarized proton and deuteron targets by circularly polarized photons. The photons were produced via internal and external bremsstrahlung from an electron beam of 48.35 GeV. Asymmetries for both positive and negative signed hadrons, and a subset of identified pions, were measured in the momentum range 10<P<30 GeV at 2.75 and 5.5 degrees. Small non-zero asymmetries are observed for the proton, while the deuteron results are consistent with zero. Recent calculations do not describe the data well.
The asymmetry for polarized photoproduction of inclusive hadrons from a polarized proton target. The errors are statistical only.
The asymmetry for polarized photoproduction of inclusive identified pions from a polarized proton target. The errors are statistical only.
Axis error includes +- 0.0/0.0 contribution (?////NOT GIVEN).
The cross section of the reaction e + e − → K + K − has been measured at the electron-positron storage ring VEPP-2M in the c.m. energy range 1.0–1.4 GeV. At energies above 1.15 GeV the experimental values of the charged kaon form factor considerably exceed the predictions of the simplest vector dominance model with ϱ, ω, ψ mesons.
No description provided.
Using the electron-position storage ring VEPP-2 an experiment has been performed in which the cross-sections of the reactions e + e − → π + π − and e + e − →K + K − were measured in the energy regi on 1.18–1.34 GeV. The experimental values of the formfactors lie higher than curves extrapolated from the ϱ- and ϕ-meson region.
No description provided.
No description provided.
Using the electron-positron storage ring VEPP-2 multipionic events have been observed at a total energy of 1.18–1.34 GeV. The experimental cross-section appears to be considerably larger than calculated within the framework of the vector dominance model for the processes e + e − → ϱπ , ϱϵ , ωπ , A 1 π . The data on the total cross-section obtained in the framework of the statistical model with 4 pions are presented.
DATA VALUES MEASURED OFF GRAPH IN JOURNAL. VALUES OF R CALCULATED FROM TOTAL MULTIHADRONIC CROSS SECTION.
The cross section of the process e+ e- ---> eta gamma has been measured in the 600-1380 MeV c.m. energy range with the CMD-2 detector. The following branching ratios have been determined: B(rho ---> eta gamma) = (3.28 +- 0.37 +- 0.23) 10^{-4}, B(omega ---> eta gamma) = (5.10 +- 0.72 +- 0.34) 10^{-4}, B(phi --> eta gamma) = (1.287 +- 0.013 +- 0.063) 10^{-2}. Evidence for the rho'(1450) ---> eta gamma decay has been obtained for the first time.
The measured Born cross section for the ETA GAMMA final state.
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