Analysis Launch Plugin Requirements

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

Example

• An example plugin that meets all of the requirements: Paul's γp→K⁺Λ Plugin

Requirements

General Requirements:

• Plugins must be checked into your home area in: https://halldsvn.jlab.org/repos/trunk/home/
• 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.
  • Available_EventStore_skims
• 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.

Recommendations

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