72 research outputs found

    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

    An electromagnetic shashlik calorimeter with longitudinal segmentation

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    A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and e/πe/\pi separation are reported.A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower very fine samplings e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and electron/pion separation are reported

    A shashlik calorimeter with longitudinal segmentation for a linear collider

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    Two techniques for longitudinal segmentation of shashlik calorimeters are proposed. Beam tests have demonstrated the technical feasibility of longitudinally segmented shashlik calorimeters in which longitudinal sampling is performed by lateral vacuum photodiodes or by using two scintillator types with different decay times. Results concerning energy resolution and e/π separation are presente

    Study of the decay K+π+ππ+γK^{+}\to\pi^{+}\pi^{-}\pi^{+}\gamma in the OKA experiment

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    A high statistics data sample of the decays of K+K^+ mesons to three charged particles was accumulated by the OKA experiment in 2012 and 2013. This allowed to select a clean sample of about 450 events with K+π+ππ+γK^{+}\to\pi^{+}\pi^{-}\pi^{+}\gamma decays with the energy of the photon in the kaon rest frame greater than 30 MeV. The measured branching fraction of the K+π+ππ+γK^{+}\to\pi^{+}\pi^{-}\pi^{+}\gamma, with EγE_{\gamma}^{*} > 30 MeV is (0.71±0.05)×105(0.71 \pm 0.05) \times 10^{-5}. The measured energy spectrum of the decay photon is compared with the prediction of the chiral perturbation theory to O(p4)(p^{4}). A search for an up-down asymmetry of the photon with respect to the hadronic system decay plane is also performed.Comment: 9 pages, 7 figures, 1 tabl
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