Updates on e CC Selection Mike Wallbank 20/3/2017 Intro Gave an - - PowerPoint PPT Presentation

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Updates on e CC Selection Mike Wallbank 20/3/2017 Intro Gave an - - PowerPoint PPT Presentation

Nov 03, 2023 190 likes •389 views

Updates on e CC Selection Mike Wallbank 20/3/2017 Intro Gave an update at the CM (link), not much has changed in the selection since. Starting to better characterise the selection; Performance of the reconstruction.

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SLIDE 1

Updates on νeCC Selection

Mike Wallbank 20/3/2017

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SLIDE 2

M Wallbank (Sheffield)

Intro

  • Gave an update at the CM (link), not much has changed in the selection since.
  • Starting to better characterise the selection;
  • Performance of the reconstruction.
  • Performance of the selection.
  • We mentioned last time I should try the reconstruction given the new version of

Pandora — however, this is currently broken (see other talks, I believe!). All Pandora has been taken from MCC7 (now nearly 6 months old).

  • Bumped up to v06_26_00.
  • Includes tracking bug in the BDT fix.

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SLIDE 3

M Wallbank (Sheffield)

Reco Chains

  • Two reconstruction chains I’m considering:
  • Develop: Pandora (track-shower separation) —> EMShower (showers);
  • New: TrackShower (new track-shower separation) —> BlurredCluster (shower clusters)

—> EMShower (showers).

  • The main problem is convincing track/shower separation.
  • I have been working on this since last September and have developed the new separation

algorithm in the second case.

  • Will compare these two chains for the rest of the talk…

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SLIDE 4

M Wallbank (Sheffield)

New: TrackShowerSep

  • Reconstruction:

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SLIDE 5

M Wallbank (Sheffield)

New: TrackShowerSep

  • Reconstruction:
  • Good shower: start point < 10 cm from true start, direction < 45 degs, completeness at least 50%.
  • Basic track shower recon: electron and longest hadron vertex track separated.


Full track shower separation: electron and all hadron vertex tracks separated.

  • Good reconstruction: basic separation and good shower.

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Numbers are on slide 14!

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SLIDE 6

M Wallbank (Sheffield)

New: TrackShowerSep

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  • Selection:
  • Cut at 0.8: efficiency 21359/43627 (49%), purity 21359/27078 (79%).
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SLIDE 7

M Wallbank (Sheffield)

New: TrackShowerSep

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  • Before selection: (sorry about the errors, need to understand what’s going on…)
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SLIDE 8

M Wallbank (Sheffield)

New: TrackShowerSep

  • After selection:

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M Wallbank (Sheffield)

Using Pandora

  • Reconstruction:

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SLIDE 10

M Wallbank (Sheffield)

Using Pandora

  • Reconstruction:
  • (Same definitions of ‘good shower’, ‘separation’ and ‘good reconstruction’ as slide 5.)

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Again, slide 14 for numbers!

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SLIDE 11

M Wallbank (Sheffield)

Using Pandora

  • Selection:

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  • Cut at 0.8: efficiency 18759/36187 (52%), purity 18759/24216 (77%).
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SLIDE 12

M Wallbank (Sheffield)

Using Pandora

  • Before selection:

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SLIDE 13

M Wallbank (Sheffield)

Using Pandora

  • After selection:

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SLIDE 14

M Wallbank (Sheffield)

Comparison

  • Reconstruction:

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  • Selection (untuned):

Efficiency Purity TrackShowerSep 49% 79% Pandora 52% 77%

TrackShowerSep Pandora Number of CC events 43942 36509 ‘Good shower’ 23023 (52%) 19923 (55%) Poor shower — start point 17891 10636 Poor shower — direction 9831 9542 Poor shower — completeness 6367 2477 Basic track shower separation 36200 (82%) 30099 (82%) Full track shower separation 32785 (75%) 29101 (80%) Good reconstruction 20399 (46%) 18391 (50%) Very good reconstruction 18971 (43%) 17921 (49%)

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SLIDE 15

M Wallbank (Sheffield)

Things I Would Like To Do

  • Run the chain which uses Pandora for track/shower separation when all issues are fixed.
  • Try to see what’s going on in the selection!
  • Characterise mva variables for different neutrino energies.
  • There are so many issues apparently present in the selection — it appears so biased!

Don’t really know where to start with all this.

  • Find a better way of tuning the cut… Dom spoke about this last time.
  • Suggestions on next steps will be much appreciated!

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SLIDE 16

M Wallbank (Sheffield)

Simple Selections with Pandora

  • Pandora doesn’t save recob::Showers so we can’t use it directly as input to the MVA.
  • Just to get an idea of how well it’s performing in general, can apply very simple selections

to the PFParticles.

  • Example selections:
  • must be at least one showering particle longer than 10 cm;
  • longest prong in event is an electron.

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SLIDE 17

M Wallbank (Sheffield)

Shower Size

  • Event must have electron shower > 10 cm.

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  • As I expected, the efficiency will tend towards one quite quickly but, since there’s no

difference between electrons and photons in Pandora PFParticles, the purity falls off sharply.

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SLIDE 18

M Wallbank (Sheffield)

Longest Particle

  • Longest particle prong is a shower.

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  • Purity is very low. Again, need more sophisticated selection!
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SLIDE 19

M Wallbank (Sheffield)

Summary

  • νe selection is challenging and lots to be understood!
  • I have a bit more time over the next few months so will look into this — I’m interested in

understanding that all a bit more!

  • I’m sure we’ll have had plenty of discussion, but any more points?
  • Next: tune the cut crudely and look at characterising the mva input variables.

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