Analysis Launch Plugin Requirements

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To make sure everything works, and to save memory and speed up the analyses, the following restrictions are placed:



General Requirements:

  • Plugins must be checked into your home area in:
  • Plugins and DReactions must have unique names: No one else can use the same names
    • E.g.: We can't run 4 plugins / reactions named "omega," so try to do something unique (e.g. "omega_pmatt").

Memory / CPU / Disk Space / Locking Requirements

  • Do locking correctly:
    • In custom actions: Use action-locks in Perform_Action(), rather than japp.
    • In plugin processor: Use plugin-locks in evnt(), rather than japp.
  • Don’t use a ton of memory (e.g. many DHistogramActions).
  • Try not to abuse memory / cpu / disk space. If too much is being used, we'll cull things as necessary to run smoothly.

Cut Requirements

  • All analyses (i.e. DReactions) must use an EventStore skim.
  • All channels must have at least the following cuts (or a very good reason not to):
    • Beam-RF Δt cut at +/- 0.5*dBeamBunchPeriod (or wider for sideband subtraction)
    • Pre-combo loose mass cuts around peaks (use same cuts (or tighter) as those in skim (if any))
    • Loose PID cuts (each particle & detector)
    • Kinematic fit converges (if any): FOM cut at -1.0.
  • These cuts must be placed before the kinematic fit is performed (except kinfit confidence level, of course).
    • The kinematic fit is performed as soon as the fit results (e.g. 4-vectors, confidence level, etc.) are requested.


Kinematic Fit

  • We've seen that the tracking errors are a problem in the FDC.
  • You can go ahead and kinematic fit, but just be careful:
    • Cut lower on the confidence level than you usually would, and study the signal loss when doing so.
    • The measured-p4 may be more accurate than the kinematic-fit p4: Histogram mass peaks with both and see which looks better for your channel
  • Be cautious about constraining masses: Once you do, you no longer have an unbiased handle on the background under the peak.
    • Mass constraints are on when P4 is fit, unless explicitly disabled

Loose CDC dE/dx Cut

  • See the example plugin above.

Loose Timing cuts

  • These still let in a lot of background, but cut ~no signal
    • It's recommended to apply these loose cuts, and to do your own momentum-dependent Δt cuts later
  • γ:
    • BCAL: +/- 1.5 ns
    • FCAL: +/- 2.5 ns
  • e+, e-:
    • TOF: +/- 1 ns
    • BCAL: +/- 2.5 ns
    • FCAL: +/- 2.5 ns
  • π+, π-:
    • TOF: +/- 2 ns (Wide to accept muons from pion decays)
    • BCAL: +/- 2.5 ns
    • FCAL: +/- 2.5 ns
  • K+, K-:
    • TOF: +/- 0.75 ns
    • BCAL: +/- 2.5 ns
    • FCAL: +/- 2 ns
  • p, pbar:
    • TOF: +/- 2.5 ns
    • BCAL: +/- 2.5 ns
    • FCAL: +/- 2.5 ns