418 research outputs found

    Air ions induced aerosol sensing by eye-safe LIDAR

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    Low concentrations aerosols quantification is rather challenging for LIDAR instruments due to eye-safety restrictions so high energy pulses cannot be utilized to improve the sensitivity. Highly sensitive but eye-save LIDAR has been developed for the quantification of the water droplet aerosol which was induced by air ions. Few days sensing of aerosols in closed tunnel revealed a strong correlation between air optical transparency (LIDAR measurements) and concentrations of positive/negative ions (ion counter Sapphir 3-M). The correlation coefficient was observed to be almost unity for the air transparency signal and air ions unipolarity coefficient. High sensitivity of the water droplet aerosol quantification makes the developed eye-safe LIDAR a perspective instrument for space resolved measurements of the air ions distribution. Space and time resolved measurements of air ions exhalation can be a new instrument for tectonic activity study including new earthquake forecasting indicators search

    Study of the ηπo\eta\pi^o system in the mass range up to 1200 MeV

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    The reaction πpηπon\pi^-p \to \eta\pi^o n has been studied with GAMS-2000 spectrometer in the secondary 38 GeV/c π\pi^--beam of the IHEP U-70 accelerator. Partial wave analysis of the reaction has been performed in the ηπo\eta\pi^o mass range up to 1200 MeV. The a0(980)a_0(980)-meson is seen as a sharp peak in S-wave. The tt-dependence of a0(980)a_0(980) production cross section has been studied. Dominant production of the a0(980)a_0(980) at a small transfer momentum tt confirms the hypothesis of Achasov and Shestakov about significant contribution of the ρ2\rho_2 exchange (IGJPC=1+2I^GJ^{PC}=1^+2^{--}) in the mechanism of a0(980)a_0(980) meson production in tt-channel of the reaction.Comment: 4 pages, 3 figures, talk given at HADRON'9

    Search for the decay KL03γK_L^0 \rightarrow 3\gamma

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    We performed a search for the decay KL03γK_L^0 \rightarrow 3\gamma with the E391a detector at KEK. In the data accumulated in 2005, no event was observed in the signal region. Based on the assumption of KL03γK_L^0 \rightarrow 3\gamma proceeding via parity-violation, we obtained the single event sensitivity to be (3.23±0.14)×108(3.23\pm0.14)\times10^{-8}, and set an upper limit on the branching ratio to be 7.4×1087.4\times10^{-8} at the 90% confidence level. This is a factor of 3.2 improvement compared to the previous results. The results of KL03γK_L^0 \rightarrow 3\gamma proceeding via parity-conservation were also presented in this paper

    A study of the etapipi channel produced in central pp interactions at 450 GeV/c

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    The reaction pp -> pf (eta pi pi) ps has been studied at 450 GeV/c. There is clear evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870). In addition, there is evidence for an a0(980)pi$ decay mode of both resonances and an f2(1270)eta decay mode of the eta2(1870). No evidence is found for a JPC = 2++ a2(1320)pi wave.Comment: 15 pages, Latex, 4 Figures Branching ratio a2pi /f2 eta correcte
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