Low-Mass Electron-Pair Anomaly in 17-GeV/cπ−pCollisions

Abstract

Inclusive $e^{+}{e}^{-}$ production in 17-GeV/c ${\pi }^{-}p$ collisions has been measured. An excess of $e^{+}{e}^{-}$ pairs over those from known sources for $0.1<~m_{\mathrm{ee}}<~0.6$ GeV and $x<\mathrm{}0.5\mathrm{}$ was found. No evidence is found for enhancements in specific final states involving electrons and photons or charged particles. The photon multiplicity associated with these pairs is measured.