User name A. Deur
Log entry time 10:29:04 on August10,2003
Entry number 110016
keyword=Cerenkov additional peak & pions
We have a sharp peak at low adc values (~1000), see fig. 1 bottom plot. The shower vs preshower plot shows a large amount of pion background (fig 1, top plot).
After tight shower vs preshower good electron cuts (fig. 2, top plot), the additional cerenkov peak disapears. So this peak is simply due to pion, although I would have expected the peak to be at lower ADC values.
Events replayed: 300000
Events passing rather tight good reconstructed quantities cuts: 165715
Events remaining after previously mentionned cut + tight shower & preshower cut (as in fig 2): 98527
Events after these 2 cuts + cerenkov cut 10
So the pion contamination is about 60% and the pid detectors look fine in term of efficiency.