energy flow studies
DESCRIPTION
Energy Flow Studies. Steve Kuhlmann Argonne National Laboratory for Steve Magill, U.S. LC Calorimeter Group. Introduction/Outline. - PowerPoint PPT PresentationTRANSCRIPT
Energy Flow Studies
Steve Kuhlmann
Argonne National Laboratory
for Steve Magill, U.S. LC Calorimeter Group
Introduction/Outline
Detector is the “Small” Detector (Si-W EM Cal, 5 mm X 5mm, R=127 cm, 17%/E) (Fe-Scint HAD Cal, 1 cm X 1cm, R=144cm, 60%/E)
Software is JAS2 and GIZMO simulation
Conversion to Geant4 “soon”
Real Track Pattern Recognition Included
Will Discuss:
Brief Photon Review and Plans
Initial work on the Real Challenge: Neutrons/KLongs
Resolution components of Hadronic Z Decays at s = 91 GeV
Assuming Perfect Identification in this Detector Configuration
•Neutrons+KLong 2.9 GeV
•Photons 1.4 GeV
•Tracks 0.25 GeV
Put together in Tesla TDR in Energy Flow algorithm
Hadronic Z Decay
Simple 3 cut analysis
1. Reject EM Clusters if within Delta-R<0.03 from Track (0.2% loss of real photons)
2. Shower Max Energy > 30 MeV (MIP=8 MeV)
3. Reject EM Cluster if Delta-R< 0.1 AND E/P<0.1
Java code is available at:
www.hep.anl.gov/stk/lc/uta/
Will be put in CVS Server “soon”
Hadronic Z Decays at s = 91 GeV
Total Hadron Level Photon Energy (GeV)
Tot
al P
hoto
n C
andi
date
Ene
rgy
Mean=0.25 GeV, Width=2.8 GeV, Perfect EFLOW Goal is 1.4 GeV.
Hadronic Z Decays at s = 91 GeV
Total Photon Energy - Total Monte Carlo Photons (GeV)
Energy Fragments from a Single 10 GeV -
Current Photon Work
1. Reject EM Clusters if within Delta-R<0.03 from Track (0.2% loss of real photons)
2. Shower Max Energy > 30 MeV (MIPS=8 MeV)
3. Reject EM Cluster if Delta-R< 0.1 AND E/P<0.1
Replace these two cuts with SLAC NNet-based ClusterID package.
(Worked on technical difficulties with Bower after UTA,
not solved)
Neutron/K0L Content of Hadronic Z Decays at s = 91 GeV
Neutron/K0L Energies in Hadronic Z Decays at s = 91 GeV
Neutrons/K0L, Mean E=4.4 GeV
Neutrons/K0L, Mean E=4.35
Study of >2 GeV Neutron/K0L overlapping >2 GeV Tracks
Study of >2 GeV Neutron/K0L overlapping >2 GeV Tracks
Study of >2 GeV Neutron/K0L overlapping >2 GeV Tracks
Angular Separation (radians) Angular Separation (radians)
Separation between Track and Closest N/K0L
Separation between N/K0L and Closest Track
Overflow bin
10% overlap within Sep<0.2
23% overlap within Sep<0.4
48% overlap within Sep<0.2
77% overlap within Sep<0.4
Overflow bin
Overlapping Showers from Other Tracks
41% overlap within Sep<0.2 72% overlap within Sep<0.4
Separation between random >2 GeV Track and Closest >2 GeV Track
Angular Separation (radians)16% overlap within Sep<0.1 59% overlap within Sep<0.3
Single 10 GeV Charged Pions: Basic Shower Widths
Angular Separation (radians)
Single 10 GeV Charged Pions: Means and Widths
Mean Width Width
All Hits 8.3 GeV 19% 60%/sqr(E)
Cone<0.4 8.1 GeV 21% 67%/sqr(E)
Cone<0.3 7.9 GeV 22% 68%/sqr(E)
Cone<0.2 7.5 GeV 22% 70%/sqr(E)
Cone<0.1 6.4 GeV 25% 80%/sqr(E)
Cone<0.075 5.8 GeV 28% 88%/sqr(E)
Single 10 GeV Charged Pions:
EM+HAD Energy (GeV) EM+HAD Energy (GeV)
All Hits Cone<0.2
These plots are with analog hadron cal, very similar with digital
Select Charged Pions isolated from other tracks in Z Decays, look
for Neutron Overlap
Cal Energy/Track P
No overlap from particle list
Overlapping Neutron/K0L
Two approaches being investigated:
1) Put calorimeter and track properties into neural
net.
List of calorimeter variables put into
ClusterID Net:
Tesla TDR approach
2) Careful removal of track depositions from Calorimeter. Used in
European package called “Snark”. Results similar to Tesla TDR, but larger
resolution tails.
Reminder, the Questions we eventually need to Answer
Detector Size and Hadron Calorimeter Resolution?
Digital or Analog Hadron Calorimeter?
Optimized segmentation for physics/costs?
Backup Slides
Question from Jeju and Calor2000: Will Hadronization or Jet Clustering Ruin Resolutions?
No, at least if backgrounds are small
Particle Energies in Hadronic Z Decays at s = 91 GeV
Charged, Mean E=2.85
Photons, Mean E=1.0
Neutrons/K0L, Mean E=4.35
Tracking cannot be assumed to be perfect, forward tracking and “curlers” are issues
Effect of ignoring charged particles below certain thresholds
Tesla TDR, is fine if achieved
Track Reconstruction Efficient Down to Pt=0.5 GeV in Barrel Region
Single 10 GeV -
Delta-R from EM Cluster to Track
EM
Clu
ster
Ene
rgy
(GeV
)
EM Clustering -- Cone 0.04
Reduce charged particle fragments with 3-layer shower max energy > 30 MeV
2 GeV Electron
2 GeV -
ddd
ddd
MeV
Also reduces neutron/K0L
clusters
Single 10 GeV -
Delta-R from EM Cluster to Track
EM
Clu
ster
Ene
rgy
(GeV
) Now With Shower Max Cut, will be improved with more detailed information on lateral/longitudinal profile
Effect of possible Photon threshold on Hadronic Z Decays at s = 91 GeV
Sum of all Hadron Level energy except photons < 0.2 GeV. Won’t apply such a cut (yet).
Photons are soft, Mean E=1.0
Hadronic Z Decays at s = 91 GeV
Simple photon finder: Remove EM Clusters within 0.03 of Track, unless track was MIP in all 30 layers. Then remove if within 0.01.
Hadronic Z Decays at s = 91 GeV
Probability of Overlapping Photon Close to a Track, 0.1% within DR<0.02, 3.3% within DR<0.1, 11% within DR<0.2
Determining Charged Particle Determining Charged Particle DepositionsDepositions
Energy deposited in last EM layer Energy deposited in last EM layer (within 0.6(within 0.600 of track) of track)
• Easy to recognize Easy to recognize MIPMIP
• Easy to determine Easy to determine 11stst layer of pion layer of pion showershower
Interactions
Single 2 GeV - Single 2 GeV Muon
Tail
OverflowsZeros
Determining Charged Particle Determining Charged Particle DepositionsDepositions
Single 2 GeV -
Energy weighted
Effect of Neutrinos in Hadronic Z Decays
One more cut motivated by Single 10 GeV -, now
either an Energy Ratio
Delta-R from EM Cluster to Track
EM
Clu
ster
Ene
rgy/
Tra
ck E