Difference between revisions of "Kinematic fitting charged particles 11/16/11"
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==Proton reconstruction== | ==Proton reconstruction== | ||
| + | * svn rev. 8574 | ||
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Distribution of thrown protons in events: | Distribution of thrown protons in events: | ||
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[[File:Proton only.png]] | [[File:Proton only.png]] | ||
| − | Protons with p<300 MeV/c are not detected, those with p>450 MeV/c | + | Protons with p<300 MeV/c are not detected, those with p>450 MeV/c almost always have sufficient hits. |
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| − | Full event sample: | + | Full event (5 particle final state) sample: |
| − | * | + | * Examine only events with proton p>450 MeV (57% of total events) |
| − | * Of these events, only | + | * 66% of events have good proton hit selection (all hits associated with proton hypothesis from proton track) |
| + | * Of these events, only 54% have good fit (confidence level from tracking chi^2 > 1%) | ||
Latest revision as of 12:29, 29 November 2011
Reaction
Looking at an all charged particle final state to study the state of the tracking code: \gamma p -> pi+ pi+ pi- pi- p.
- 50,000 events
- svn revision 8540
Kinematic fit
All combinations of track hypotheses that produce the correct final state are kinematically fit. Constraint is overall conservation of 4-momentum.
- 41% of events have sufficient particles (>=3 positive tracks, >=2 negative tracks)
- Of these, 9% have kinematic fit confidence level>1% (4% of total events)
3-momentum
Kinematic fit is dependent on errors, PID. Try to simplify things...
Look at events with exactly 5 tracks (3 positive, 2 negative) and look at sum of reconstructed 3-momentum from all tracks.
28% of events have exactly 5 tracks
2400 events in region outlined in red.
Proton reconstruction
- svn rev. 8574
Distribution of thrown protons in events:
Look at sample of proton-only events with same momentum distribution.
Protons with p<300 MeV/c are not detected, those with p>450 MeV/c almost always have sufficient hits.
Full event (5 particle final state) sample:
- Examine only events with proton p>450 MeV (57% of total events)
- 66% of events have good proton hit selection (all hits associated with proton hypothesis from proton track)
- Of these events, only 54% have good fit (confidence level from tracking chi^2 > 1%)
