• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    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.
    Some numbers:
    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.

    FIGURE 1

    FIGURE 2