1 June 26. Punch-through detection using Muon Spectrometer Showers - - PowerPoint PPT Presentation

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1 June 26. Punch-through detection using Muon Spectrometer Showers - - PowerPoint PPT Presentation

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1 June 26. Punch-through detection using Muon Spectrometer Showers & MET resolution and tails Atlas Hadronic Calibration Workshop 23-27 June 2009 Johan Lundberg, with David Berge CERN, 2009 slide 2-6: Slides for MET session, Friday,

slide-1
SLIDE 1

Johan Lundberg, David Berge, CERN

Punch-through detection using ‘Muon Spectrometer Showers’ & MET resolution and tails

Atlas Hadronic Calibration Workshop 23-27 June 2009 Johan Lundberg, with David Berge CERN, 2009

slide 2-6: Slides for MET session, Friday, 26 2009 slide 8-27: Submitted material June 26.

1

Fri, 26Jun,

slide-2
SLIDE 2

Johan Lundberg, David Berge, CERN

Event 271117

Example of a suspected punch-through event with many muon hits

2

MuonSpShowerContainer contains, for the muon spectrometer,

  • counts of hits
  • counts of muon segments

within a cone around jet axes Developed and used before by Frank Paige, Stephane Willocq, Ketevi Assamagan, ...

Study of relation between very large Fake MET (eg. > 100 GeV) and many muon system hits ETA: 0.0 SUM_ET: 2 TeV |MET|: 172 GeV

Fri, 26Jun,

slide-3
SLIDE 3

Johan Lundberg, David Berge, CERN

3

Energy error: Delta E = True-Reco Jet energy vs the number of Muon shower hits for second jet. There’s a clear correlation, but also a very large spread. For very high numbers of muon hits the mean energy error is ~ 100 GeV For high ET samples muon shower hits are insensitive to pileup (ref to backup slides) di-jet sample, J6

Mean Energy error Mean Energy error Mean number

  • f Muon Hits

Mean number

  • f Muon Hits

Correlation between jet Energy Error (Rec-Truth) and muon shower hits

For all plots (unless stated): dijet samples: user09.KojiTerashi.mc08.105017. J*_pythia_jetjet.recon.DPD_NOSKIM. e344_s479_r635_DPDMaker000164_p1 For pileup comparisons: user09.MichiruKaneda.mc08.105017. J*_pythia_jetjet.recon.DPD_NOSKIM. e344_s479_d150_r642_DPDMaker000164_p1

3

Fri, 26Jun,

slide-4
SLIDE 4

Johan Lundberg, David Berge, CERN

P > 3 sigma = .0027 for a Gaussian

Fraction of di-jet events appearing in MET tails ...compared to all events at the same Sum ET With and without a cut: Muon Shower Hits < 150

fraction > 250 GeV improved about a factor of 2 with no cut with cut Above ~ 1.5 TeV : non-Gaussian contribution enhances the tails by a factor > 15

4

Sum ET (GeV)

Sum ET (GeV) METx resolution, GeV O Combined (J0--J8) Resolution

  • -- CSC fit: 0.55 Sqrt( SumET )

This fit: 0.49 Sqrt( SumET ) Fit @: <2500 GeV FakeMET>250 GeV FakeMET>100 GeV FakeMET> 3 sigma ~7%

Fri, 26Jun,

slide-5
SLIDE 5

Johan Lundberg, David Berge, CERN

5

Number of events for 100/pb

(production cross sections)

No Pileup

1 event/pb

Number of events for different fake MET cuts

~ factor 2 improvement with cut on muon shower hits

low FakeMet events not influenced much

Fri, 26Jun,

slide-6
SLIDE 6

Johan Lundberg, David Berge, CERN

6

Summary

  • Muon shower hits are correlated to fake MET, with large noise and spread.
  • Above ~ 1.5 TeV the fake MET tails are not Gaussian: The amount of events with

fake MET >3 sigma is enhanced by a factor > ~ 15.

  • In very High fake MET events (>250 GeV) about 50% have a very high count (>150)
  • f Muon shower hits.
  • Muon Spectrometer hits and large Fake MET insensitive to Pileup.
  • Rate of these events expected to be low

Questions

  • Could we cut/flag such events in e.g. SuSy analyses?
  • Could we use muon spectrometer showers for

calibration improvements?

Fri, 26Jun,

slide-7
SLIDE 7

Johan Lundberg, David Berge, CERN

Standard cone jet, Cone7 H1 TowerJets phi/eta box : half size = 0.4 dijet samples: user09.KojiTerashi.mc08.105017.J*_pythia_jetjet.recon. DPD_NOSKIM.e344_s479_r635_DPDMaker000164_p1 For pileup comparisons: user09.MichiruKaneda.mc08.105017.J*_pythia_jetjet.recon. DPD_NOSKIM.e344_s479_d150_r642_DPDMaker000164_p1

  • ffline 15.1

7

Fri, 26Jun,

slide-8
SLIDE 8

Johan Lundberg, David Berge, CERN

8

Outer TileCal layer energy deposition, Second Jet, vs number of muon Hits

Fri, 26Jun,

slide-9
SLIDE 9

Johan Lundberg, David Berge, CERN

Cut: FakeMET<10GeV

Cut: FakeMET>100GeV

Angle Angle MS hits (Max)

9

Correlation; MET to Jet angle vs Number of muon shower hits Can we use muon hits to find large fake MET events

It’s clear that FakeMet in dijets points towards one of the leading jets (often 2:nd). The angle between fake MET and the jet (out of the 4 leading) with the highest number of muon shower hits. J6 sample. Could be useful to make cleaning cuts in this space

  • Needs testing with

example analyses MS hits (Max)

Fri, 26Jun,

slide-10
SLIDE 10

Johan Lundberg, David Berge, CERN

Submitted material

Punch-through detection using ‘Muon Spectrometer Showers’ & MET resolution and tails Atlas Hadronic Calibration Workshop 23-27 June 2009 Johan Lundberg, with David Berge CERN, 2009

June 23

10

Fri, 26Jun,

slide-11
SLIDE 11

Johan Lundberg, David Berge, CERN

11

  • Summary/Conclusion
  • MuonSpShowerContainer, what is it? Correlation to Jet Energy Error
  • Fit of Jet Resolution
  • Fraction and Number of events in MET tails, with and without Cut on MuonSpShower hits
  • + Fit resolution, Fraction and number of events with Pileup

Backup

  • Estimation of MET resolution: sigma(Truth -Rec)

With/Without pileup, With/Without cuts on Muon Spectrometer Shower hits

  • Number of dijet events for 100/pb

For normal dijet and pileup samples

  • Number of Muon Spectrometer Shower hits vs eta, and Jet Energy
  • Number of Muon Spectrometer Shower hits vs Jet Energy Error for

different eta-bands

  • Cleaning (e.g. for SuSy context) using MET to Jet Angle vs muon

spectrometer shower hits. (with and without pileup)

  • Muon spectrometer shower hits vs Jet Energy Error for 3 leading jets.
  • Tools etc.

Fri, 26Jun,

slide-12
SLIDE 12

Johan Lundberg, David Berge, CERN

ETA: -0.00 SUM_ET 2 TeV |MET|: 172 GeV METx: -62 GeV METy: 160 GeV Event 271117

Example of a suspected punch-through event with many muon hits Summary/Conclusion

  • Muon spectrometer shower hits are correlated to fake

MET and jet energy error, with large noise and spread.

  • Above ~ 1.5 TeV the fake MET tails are not Gaussian:

The amount of events with fake MET >3 sigma of fitted MET resolution is enhanced by a factor > ~ 15.

  • In very High fake MET events (>250 GeV) about 50%

have a very high count of (>150) of Muon shower hits.

12

Fri, 26Jun,

slide-13
SLIDE 13

Johan Lundberg, David Berge, CERN

MuonSpShowerContainer

contains, for the muon spectrometer,

  • counts of hits
  • counts of muon segments

within a cone around jet axes

13

Energy error: Delta E = True-Reco Jet energy vs the number of Muon spectrometer shower hits for second jet. There’s a clear correlation, but also a very large spread. For very high numbers of muon hits the mean energy error is ~ 100 GeV For high ET samples muon spectrometer shower hits are insensitive to pileup (ref to backup slides) di-jet sample, J6

Mean Energy error

Developed and used before by Frank Paige, Ketevi Assamagan, ...

Mean Energy error Mean number

  • f Muon Hits

Mean number

  • f Muon Hits

Fri, 26Jun,

slide-14
SLIDE 14

Johan Lundberg, David Berge, CERN

14

Estimation of MET resolution: sigma(Truth -Rec)

Dijet sum : J0 to J8

Dijet sample, No PILEUP

Fit @: <2500 GeV Resolution fitted within +/- 2 sigma Resolution fitted within +/- 2 sigma

Fri, 26Jun,

slide-15
SLIDE 15

Johan Lundberg, David Berge, CERN

15

Fraction of events which have large fake MET

P > 3 sigma = .0027 for a Gaussian

Without PILEUP

With Cut : Muon hits<150

compared to all events at the same SumET fraction > 250 improved with no cut with cut Above ~ 1.5 TeV : non-Gaussian contribution enhances the tails by a factor > 15

Fri, 26Jun,

slide-16
SLIDE 16

Johan Lundberg, David Berge, CERN

16

Fraction of event which have large fake MET

P > 3 sigma = .0027 for a Gaussian Above ~ 1.5 TeV : non-Gaussian contribution enhances the tails by a factor > 15

Fraction of events which have large fake MET

compared to all events at the same SumET

WITH PILEUP

low statisics

Fri, 26Jun,

slide-17
SLIDE 17

Johan Lundberg, David Berge, CERN

17

Number of events for 100/pb No Pileup

Number of events for different fake MET cuts

~ factor 2 improvement with cut on muon spectrometer shower hits

low FakeMet events not influenced too much

Fri, 26Jun,

slide-18
SLIDE 18

Johan Lundberg, David Berge, CERN

18

~ factor 2 improvement with cut on muon spectrometer shower hits WITH PILEUP

Number of events for different fake MET cuts

Number of events for 100/pb

Fri, 26Jun,

slide-19
SLIDE 19

Johan Lundberg, David Berge, CERN

19 More detailed slides

  • Estimation of MET resolution: sigma(Truth -Rec)

With/Without pileup, With/Without cuts on Muon Spectrometer Shower hits

  • Number of dijet events for 100/pb

For normal dijet and pileup samples

  • Number of Muon Spectrometer Shower hits vs eta, and Jet Energy
  • Number of Muon Spectrometer Shower hits vs Jet Energy Error for

different eta-bands

  • Cleaning (e.g. for SuSy context) using MET to Jet Angle vs muon

spectrometer shower hits. (with and without pileup)

  • Muon spectrometer shower hits vs Jet Energy Error for 3 leading jets.
  • Tools etc.

Fri, 26Jun,

slide-20
SLIDE 20

Johan Lundberg, David Berge, CERN

20

Estimation of MET resolution: sigma(Truth -Rec)

Dijet sum : J0 to J8

No PILEUP With a Cut : Muon Spectrometer Shower hits < 150

Resolution (fitted within +/- 2 sigma) is not improved much

Fit @: <2500 GeV

Fri, 26Jun,

slide-21
SLIDE 21

Johan Lundberg, David Berge, CERN

21

Estimation of MET resolution: sigma(Truth -Rec)

Dijet sum : J0 to J8

WITH PILEUP Without any cut

(Pileup sample influenced the same way) Lack of statistics for J0 (next slide) Pileup degrades resolution @ <1.5 TeV

This fit can not be trusted, due to the large spread around 1500 Fit @: <2500 GeV

Fri, 26Jun,

slide-22
SLIDE 22

Johan Lundberg, David Berge, CERN

22

Number of dijet events for 100/pb Normal dijet samples Number of dijet events for 100/pb Pileup dijet samples

Lack of statistics for J0

reference slide for previous page

Fri, 26Jun,

slide-23
SLIDE 23

Johan Lundberg, David Berge, CERN

23

Fraction of events which have large fake MET

P > 3 sigma = .0027 for a Gaussian Above ~ 1.5 TeV : non-Gaussian contribution enhances the tails by a factor > 15 compared to all events at the same SumET

Without PILEUP

Fri, 26Jun,

slide-24
SLIDE 24

Johan Lundberg, David Berge, CERN

24 di-jet sample, J6.

reconstructed variables

Muon hits VS eta leading jet Muon hits VS rec E leading jet Muon hits VS eta next to leading jet Muon hits VS rec E next to leading jet

Fri, 26Jun,

slide-25
SLIDE 25

Johan Lundberg, David Berge, CERN

25 di-jet sample, J6. Energy error as function of number of hits for second recojet.

Y-profile X-profile

The correlation is quite similar with respect to eta

Fri, 26Jun,

slide-26
SLIDE 26

Johan Lundberg, David Berge, CERN

26 Can we use muon hits to find large fake MET events for cleaning, e.g. in a susy analysis?

It’s clear that FakeMet in dijets point towards one of the leading jets (often 2:nd). The following slides show the angle between fake MET and the jet (out of the 4 leading) with the highest number of muon spectrometer shower hits.

J6.

FakeMET<10GeV ALL FakeMET>100GeV FakeMET>50GeV

Could be useful to make cleaning cuts in this space

  • Needs testing with example analyses

Angle Angle Angle Angle MS hits (Max) MS hits (Max) MS hits (Max) MS hits (Max)

Fri, 26Jun,

slide-27
SLIDE 27

Johan Lundberg, David Berge, CERN

27 J6.

FakeMET<10GeV ALL FakeMET>100GeV FakeMET>50GeV

Could be useful to make cleaning cuts in this space

  • Needs testing with example analyses

Now, the same as last slide, but with pileup. It’s very similar (colour scale is different) - Again, pileup not exciting for J6, but adds to the low MS-hits regions at lower energies

Angle Angle Angle Angle MS hits (Max) MS hits (Max)

Fri, 26Jun,

slide-28
SLIDE 28

Johan Lundberg, David Berge, CERN

MuonSpShowerContainer

contains, for the muon spectrometer,

  • counts of hits
  • counts of muon segments

within a cone around jet axes

28

Delta E = True-Reco Jet energy vs the number of Muon spectrometer shower hits for the respective jet

di-jet sample, J6

For high ET samples muon spectrometer shower hits are insensitive to pileup (ref to backup slides) Y-profile X-profile

This object has been developed and used in before by Frank Paige, Ketevi Assamagan, ...

Fri, 26Jun,

slide-29
SLIDE 29

Johan Lundberg, David Berge, CERN

29 Samples and tools

Normal dijet sample user09.KojiTerashi.mc08.105017.J8_pythia_jetjet.recon.DPD_NOSKIM. e344_s479_r635_DPDMaker000164_p1 Pileup sample used: user09.MichiruKaneda.mc08.105017.J8_pythia_jetjet.recon.DPD_NOSKIM. e344_s479_d150_r642_DPDMaker000164_p1 Tools: SFrame for histograms and plots (https://twiki.cern.ch/twiki/bin/view/Main/SFramePage) Athena-JiveXML, Atlantis VP1

Fri, 26Jun,