Search for prompt neutrinos and penetrating neutral particles in a beam-dump experiment at Brookhaven National Laboratory

Abstract

Results are presented from a beam-dump experiment at Brookhaven National Laboratory using the 7-ft bubble chamber to search for prompt sources of neutrinos and the interactions or decays into $\ensuremath{\gamma}\ensuremath{\gamma}$ or ${e}^{+}{e}^{\ensuremath{-}}$ of light, penetrating neutral particles (such as the axion). The observed events are all consistent with representing neutrinos from ordinary sources. We place upper limits on axion production that are below theoretical estimates. We also set upper limits on associated production of the charmed $D$ meson.