A measurement of the parity-violating parameter A(B) with electrons at the SLD using a neural network

The parity violating parameter Ab of the Z0 → bb¯ coupling has been measured directly using the angular dependence of the Z 0-pole polarized cross section. Bottom hadrons are tagged via semileptonic decays. The semileptonic channel used in this analysis is the electron channel. The analysis takes advantage of a new Neural Network algorithm to classify electrons according to the sources: b → e, b → c → e, c → e and background events. Based on the 1996–1998 SLD sample of 350,000 Z0 decays produced with highly polarized electron beams, this technique yields: Ab = 0.877 ± 0.050(stat) ± 0.028(syst).