M. Acciarri et al., SEARCH FOR NEW PHYSICS IN ENERGETIC SINGLE-PHOTON PRODUCTION IN E(-) ANNIHILATION AT THE Z-RESONANCE()E(), Physics letters. Section B, 412(1-2), 1997, pp. 201-209
Using a sample of e(+)e(-) annihilation events collected with the L3 d
etector at the Z resonance corresponding to an integrated luminosity o
f 137 pb(-1), we have searched for anomalous production of gamma X fin
al states where X represents stable, weakly interacting particles and
the photon energy is greater than 15 GeV. The sample of events found i
s consistent with Standard Model expectations. Upper limits are set on
Z gamma couplings, the tau neutrino magnetic moment, and the branchin
g ratio for Z --> gamma X. (C) 1997 Elsevier Science B.V.