Track-First E-flow Algorithm

Analog vs. Digital Energy Resolution for Neutral Hadrons

Towards Track/Cal hit matching

Photon Finding

Plans

E-flow Algorithm Development Status at E-flow Algorithm Development Status at ANLANL

S. Chekanov, S. Kuhlmann, S. Magill,B. Musgrave

Argonne National Laboratory

Track-First E-Flow AlgorithmTrack-First E-Flow Algorithm

1st step - Track extrapolation thru Cal

– substitute for Cal cells in road (core + tuned outlyers)

- analog or digital techniques in HCAL

– Cal granularity/segmentation optimized for separation of charged/neutral clusters

2nd step - Photon finder (use analytic long./trans. energy profiles, ECAL shower max, etc.)

3rd step - Jet Algorithm on Tracks and Photons

4th step – include remaining Cal cells (neutral hadron energy) in jet (cone?) -> Digital HCAL?

Needs no cal cell clustering?!

Motivation for Track-First Motivation for Track-First EFAEFA

Charged particles~ 62% of jet energy

-> Tracker /pT ~ 5 X 10-5 pT

190 MeV to 100 GeV Jetenergy resolution

Photons ~ 25% of jet energy

-> ECAL /E ~ 15-20%/E : ~900 MeV to energy resolution

Neutral Hadrons ~ 13% of jet energy

-> HCAL <3 GeV to resolution -> /E < 80%/E

W, Z

30%/M

75%/M

Can explore EWSB thru the interactions :e+e- -> WW and e+e- -> ZZ

-> Requires Z,W ID from dijets-> Can’t use (traditional) constrained fits

Compare to digital

KKLL00 Analysis – SD Analysis – SD

DetectorDetectorAnalog ReadoutAnalog Readout

/mean ~ 26%

Average : ~43 MeV/hit Analog EM + Digital HAD x calibration

Slope = 23 hits/GeV

KKLL00 Analysis – SD Analysis – SD

DetectorDetectorDigital ReadoutDigital Readout

/mean ~ 24%

Neutral Hadron Measurement Neutral Hadron Measurement SummarySummary SD DetectorSD Detector

~1 X0 sampling SS/Scintillator Sandwich 4I

KL0 Analog Resolution (/mean) ~26%

KL0 Digital Resolution (/mean) ~24%

Contribution to resolution of a 100 GeV Jet from :Tracks -> ~0.2 GeVPhotons -> ~0.9 GeV (J.-C. Brient -> 1.1 GeV)

Digital Neutral Hadrons -> ~3.1 GeVDigital Neutral Hadrons -> ~3.1 GeV

“Confusion” -> 0.0 (perfect E-flow)

Total Jet Resolution : Total Jet Resolution : /E ~ 32%//E ~ 32%/EE

-0.05 0.00 0.05

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

Track Extrapolation/Cal Cell Track Extrapolation/Cal Cell SubstitutionSubstitution

1st layer SD EMCAL

Charged Pions in SD Cal - Charged Pions in SD Cal - vs vs

Last layer SD HCAL1st layer SD HCAL

Mid layer SD EMCAL

Shower “core” is really MIP signal of pion before showering

Can tune “outlying” shower area separately for ECAL and HCAL

“Core” absent after shower starts

ee++ee-- -> Z (pole at 91 -> Z (pole at 91 GeV)GeV)

Durham Jet Algorithm (ycut = 0.5)

Correlated 45.5 GeV, back-to-back jets

More Dijet More Dijet MassesMasses

MC Particles - neutrinos

MC Particles – neutrinos– charged particles < 1 GeVCal Clusters (cheater)

Cut at |costh| < 0.5 and pT > 2

GeV for MC and Data tracks

MC Track Transverse Momentum (GeV)Track Transverse Momentum (GeV)

Track Track ReconstructionReconstructionvs MC Truthvs MC Truth

Comparison of Track Dijet Comparison of Track Dijet MassesMasses

Tracks shifted compared to MC – lost tracks?,just wrong mass?

Tightened barrel cut -> |costh| < 0.2!

Reconstructed tracks and MCparent energymcE 5.6 trackE 5.6 ct -0.38mcE 7.9 trackE 7.9 ct -0.34mcE 3.6 trackE 3.6 ct -0.47mcE 5.5 trackE 5.5 ct 0.44mcE 8.6 trackE 8.57 ct 0.44mcE 2.9 trackE 2.9 ct -0.34

Full list of MC charged particlesmctra E 5.6 ct -0.38mctra E 7.9 ct -0.34mctra E 2.9 ct -0.34mctra E 3.6 ct -0.47mctra E 3.4 ct 0.39 *****mctra E 4.8 ct 0.46 *****mctra E 5.5 ct 0.44mctra E 8.6 ct 0.44

Reconstructed Track + MC NeutralsReconstructed Track + MC Neutrals

Sum of Jet Energies (GeV)

Energy Fractional

Difference

MassFractional

Difference

Shower Max Photon Shower Max Photon FinderFinder

Based on additional clustering of “Simple Clusters” :

1) Cluster all simple clusters in ECAL using a cone of radius 0.04 (contains 99% of photon energy)

2) Loop over all reconstructed tracks, removing matching “photon” candidates within a 0.04 cone

3) Calculate shower max energy -> add energy in layers 3,4,5 (2.8 -> 4.2 X0)

10 GeV -

PassedPassed

Conversion, Conversion, but?but?

A simple variable to separate photons from neutrons etc., energy near shower max in EM

2 GeV e-

2 GeV -

Performance of Shower Max VariablePerformance of Shower Max Variable

!

MC MC ComparisonsComparisons

Photon Contribution to Photon Contribution to ResolutionResolution

Width of a fit around the peak ~ 4 GeV – need 1 GeV

Plans for HCAL Optimization StudiesPlans for HCAL Optimization Studies

• Study absorber type/thickness with JAS-> shower containment, hit density, single particle -> shower containment, hit density, single particle

energy resolutionenergy resolution

• Tune transverse granularity and longitudinal segmentation in JAS-> separation of charged/neutral hadron showers-> separation of charged/neutral hadron showers

• Test both analog and digital readout techniques-> comparison of energy/hit density readout methods-> comparison of energy/hit density readout methods

• Develop and optimize E-flow algorithm(s)-> -> dijet mass resolution dijet mass resolution