2,877 research outputs found

    Resonance structure in the {\gamma}{\gamma} and π0π0\pi^0\pi^0 systems in dC interactions

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    Along with π0\pi^0 and {\eta} mesons, a resonance structure in the invariant mass spectrum of two photons at M{\gamma}{\gamma} = 360 \pm 7 \pm 9 MeV is observed in the reaction d + C \rightarrow {\gamma} + {\gamma} + X at momentum 2.75 GeV/c per nucleon. Estimates of its width and production cross section are {\Gamma} = 64 \pm 18 MeV and σγγ\sigma_{\gamma\gamma} = 98 \pm 24 {\mu}b, respectively. The collected statistics amount to 2339 \pm 340 events of 1.5 \cdot 10^6 triggered interactions of a total number ~ 10^12 of dC-interactions. The results on observation of the resonance in the invariant mass spectra of two π0\pi^0 mesons are presented: the data obtained in the d + C \rightarrow {\gamma} + {\gamma} reaction is confirmed by the d + C \rightarrow π0\pi^0 + π0\pi^0 reaction: Mπ0π0M_{\pi^0\pi^0} = 359.2 \pm 1.9 MeV, {\Gamma} = 48.9 \pm 4.9 MeV; the ratio of Br(R\rightarrow{\gamma}{\gamma}) / Br(R\rightarrowπ0π0\pi^0\pi^0) = (1.8 {\div} 3.7)\cdot10^-3.Comment: 10 pages, 11 figure

    Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

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    This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.Comment: 24 pages, 15 figure
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