A search for direct electron production inpp interactions at 70GeV/c

A search for directly produced electrons in 70 GeV/cpp interactions has been performed using BEBC equipped with a hydrogen filled track sensitive target surrounded by a hydrogen/neon blanket. No candidates for single electron production with momentump e >500 MeV/c were found in a sample of 66,000 primary interactions. This result places an upper limit of 2.5 μb on the cross section for singlee ± production at the 90% confidence level. The corresponding upper limit on the charmed particle production cross section in 14 μb. From the observation of 7 events producing ane +e− pair with mass, $$m_{e^ + e^ - } > m_{\pi ^0 } $$ thee ±/π± ratio from this source is estimated to be (0.7±0.2)×10−4.