We present a measurement of the cross section for hadron production by e+e− annihilation in the vicinity of the previously observed resonance near 3.77 GeV. The data are used to determine the parameters of the ψ(3770) resonance. The values found are: mass, 3764±5 MeV/c2, total width, 23.5±5 MeV, and partial width to electron pairs, 276±50 eV.
THESE RESULTS ARE ALSO IN THE THESIS OF R. H. SCHINDLER, SLAC-219 (1979), THE RECORD OF WHICH CONTAINS THE TABULATED CROSS SECTIONS.
BREIT-WIGNER RESONANCE PLUS BACKGROUND FIT TO RADIATIVELY CORRECTED DATA YIELDS RESONANCE MASS OF 3764 +- 5 MEV, TOTAL WIDTH OF 23.5 +- 5 MEV AND PARTIAL WIDTH TO ELECTRON PAIRS OF 276 +- 50 EV.
PEAK CROSS SECTION FOR D MESON PAIR PRODUCTION AT PSI(3770) RESONANCE. J/PSI, PSI(3684) AND CONTINUUM BACKGROUND (R=2.5) SUBTRACTED.
The production of multipion events by e + e − annihilation has been measured at centre of mass energies 915,990 and 1076 MeV. Both channels e + e − → π + π − π o and e + e − → π + π − π + π − have been analysed. An energy threshold effect analysed. An energy threshold effect around 919 MeV ( m ω + m π o ) has been evidenced for the π + π − π o π o channel and the cross section is consistent with the quasi two-body process e + e − → ωπ o . The cross section for π + π − π + π − is lower by an order of magnitude and increases with the energy.
SYSTEMATIC ERROR INCLUDED. RADIATIVE EFFECT (<15 PCT) INCLUDED.
MULTIHADRON PRODUCTION CROSS SECTION DEDUCED AS SUM OF FOUR PION CHANNELS.
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