1.  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 ANL S. Chekanov, S. Kuhlmann, S. Magill, B. Musgrave Argonne National Laboratory

2. Track-First E-Flow Algorithm 1 st 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 2 nd step - Photon finder (use analytic long./trans. energy profiles, ECAL shower max, etc.) 3 rd step - Jet Algorithm on Tracks and Photons 4 th step – include remaining Cal cells (neutral hadron energy) in jet (cone?) -> Digital HCAL? Needs no cal cell clustering?!

3. Motivation for Track-First EFA Charged particles ~ 62% of jet energy -> Tracker  /p T ~ 5 X 10 -5 p T 190 MeV to 100 GeV Jet energy resolution Photons ~ 25% of jet energy -> ECAL  /E ~ 15-20%/  E : ~900 MeV to energy resolution Neutral Hadrons ~ 13% of jet energy -> HCAL  /E < 80%/  E W, ZW, 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

4. Compare to digital  K L 0 Analysis – SD Detector Analog Readout  /mean ~ 26%

5. Average : ~43 MeV/hitAnalog EM + Digital HAD x calibration Slope = 23 hits/GeV K L 0 Analysis – SD Detector Digital Readout  /mean ~ 24%

6. Neutral Hadron Measurement Summary SD Detector ~1 X 0 sampling SS/Scintillator Sandwich 4 I K L 0 Analog Resolution (  /mean) ~26% K L 0 Digital Resolution (  /mean) ~24% Contribution to resolution of a 100 GeV Jet from : Tracks -> ~0.2 GeV Photons -> ~0.9 GeV (J.-C. Brient -> 1.1 GeV) Digital Neutral Hadrons -> ~3.1 GeV “Confusion” -> 0.0 (perfect E-flow) Total Jet Resolution :  /E ~ 32%/  E

7. Track Extrapolation/Cal Cell Substitution 1 st layer SD EMCAL Charged Pions in SD Cal -  vs  Last layer SD HCAL1 st 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

8. e + e - -> Z (pole at 91 GeV) Durham Jet Algorithm (ycut = 0.5) Correlated 45.5 GeV, back-to-back jets

9. More Dijet Masses MC Particles - neutrinos MC Particles – neutrinos – charged particles < 1 GeV Cal Clusters (cheater)

10. Cut at |costh| 2 GeV for MC and Data tracks MC Track Transverse Momentum (GeV) Track Transverse Momentum (GeV) Track Reconstruction vs MC Truth

11. Comparison of Track Dijet Masses Tracks shifted compared to MC – lost tracks?, just wrong mass? Tightened barrel cut -> |costh| < 0.2! Reconstructed tracks and MC parent energy mcE 5.6 trackE 5.6 ct -0.38 mcE 7.9 trackE 7.9 ct -0.34 mcE 3.6 trackE 3.6 ct -0.47 mcE 5.5 trackE 5.5 ct 0.44 mcE 8.6 trackE 8.57 ct 0.44 mcE 2.9 trackE 2.9 ct -0.34 Full list of MC charged particles mctra E 5.6 ct -0.38 mctra E 7.9 ct -0.34 mctra E 2.9 ct -0.34 mctra E 3.6 ct -0.47 mctra E 3.4 ct 0.39 ***** mctra E 4.8 ct 0.46 ***** mctra E 5.5 ct 0.44 mctra E 8.6 ct 0.44

12. Reconstructed Track + MC Neutrals Sum of Jet Energies (GeV) Energy Fractional Difference Mass Fractional Difference

13. Shower Max Photon Finder 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 X 0 ) 10 GeV  -

14. Passed

15. Conversion, but?

16. A simple variable to separate photons from neutrons etc., energy near shower max in EM 2 GeV e - 2 GeV  - Performance of Shower Max Variable !

17. MC Comparisons

18. Photon Contribution to Resolution Width of a fit around the peak ~ 4 GeV – need 1 GeV

19. Plans for HCAL Optimization Studies Study absorber type/thickness with JAS -> shower containment, hit density, single particle energy resolution Tune transverse granularity and longitudinal segmentation in JAS -> separation of charged/neutral hadron showers Test both analog and digital readout techniques -> comparison of energy/hit density readout methods Develop and optimize E-flow algorithm(s) ->  dijet mass resolution 