2001/06/12 by M. N. Achasov, М. Н. Ачасов, V. M. Aulchenko +42 · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex
paper · pdf · doi:10.1103/physrevd.65.032002
published as Phys.Rev.D65:032002,2002 · 22 pages REVTEX and 19 figures
arxiv created 2001/06/12 · openalex publication_date 2002/01/07 · arxiv updated 2010/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The invariant mass spectra of the \ensuremathπ+\ensuremathπ^\ensuremath- and \ensuremathπ^\ifmmode±\else\textpm\fi\ensuremathπ0 pairs in the process e+e^\ensuremath-\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathπ0 were studied in the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy region √(s)\ensuremath≃1020 MeV. These studies were based on about 0.5\ifmmode×\else\texttimes\fi106 events. The spectra were analyzed in the framework of the vector meson dominance model. It was found that the experimental data can be described assuming the e+e^\ensuremath-\ensuremath→\ensuremathρ\stackrel\ensuremath→\ensuremathπ\ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathπ0 transition only. An upper limit on the branching ratio of the \ensuremathφ(1020)\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathπ0 decay through intermediate states different from \ensuremathρ\ensuremathπ was obtained at the 90% confidence level: B(\stackrel\ensuremath→\ensuremathφ\ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathπ0)<6\ifmmode×\else\texttimes\fi10^\ensuremath-4. The \ensuremathρ-meson mass and width which follow from the spectra analysis are m_\ensuremathρ=775.0\ifmmode±\else\textpm\fi1.3 MeV, \ensuremathΓ_\ensuremathρ=150.4\ifmmode±\else\textpm\fi3.0 MeV. The mass difference of the neutral and charged \ensuremathρ mesons was found to equal m_\ensuremathρ^\ifmmode±\else\textpm\fi\ensuremath-m_\ensuremathρ0=\ensuremath-1.3\ifmmode±\else\textpm\fi2.3 MeV. In the \ensuremathπ+\ensuremathπ^\ensuremath- mass spectrum the \ensuremathρ\ensuremath-\ensuremathω interference was seen at a two standard deviation level.