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Cal Cluster ID (a.k.a. Eflow)

Cal Cluster ID (a.k.a. Eflow). Gary R. Bower, SLAC Santa Cruz LCD Workshop June 28, 2002. Acknowledgement. Ron Cassell has made many essential contributions to this project. Outline. This is a work in progress. (Very preliminary) results first! Describe test data sets and testing methods.

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Cal Cluster ID (a.k.a. Eflow)

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  1. Cal Cluster ID(a.k.a. Eflow) Gary R. Bower, SLAC Santa Cruz LCD Workshop June 28, 2002

  2. Acknowledgement • Ron Cassell has made many essential contributions to this project. G.R.Bower - Santa Cruz LCD Workshop

  3. Outline • This is a work in progress. • (Very preliminary) results first! • Describe test data sets and testing methods. • Efficiencies and fake rates. • Details (as time permits) • Approach to problem • Discriminator tools • Discriminator capabilities • Summary • Next Steps G.R.Bower - Santa Cruz LCD Workshop

  4. Test procedure • Three datasets of 1000 single particle events. • piminus, gamma, and K0L • 1-50 Gev momentum • In barrel, within 45o of perpendicular to beam • Make contiguous hit clusters • Ignore clusters with energy < 0.5 GeV • Treat most energetic cluster as primary deposition • Treat second most energetic cluster as fragment. • Test both primary and secondary cluster • Is it a gamma, piminus, K0L, and/or fragment? G.R.Bower - Santa Cruz LCD Workshop

  5. ID result:gamma piminus K0L fragment Input: gamma piminus KOL fragment G.R.Bower - Santa Cruz LCD Workshop

  6. Multiple ID rates G.R.Bower - Santa Cruz LCD Workshop

  7. Philosophy of Technique • The Eflow problem: a common approach: • solve it with a clever cluster builder but still need to identify shower origin. • Assumes showers fragment badly. • Assumes showers overlap each other. • We take a different approach: • work with (simple) clusters of contiguous hits. • distinguish origins based on cluster properties G.R.Bower - Santa Cruz LCD Workshop

  8. Fragmentation problem?input piminus G.R.Bower - Santa Cruz LCD Workshop

  9. “Secret” to solving fragmentation problem • Combine EM and Had clusters using contiguous hits cluster builder by Ron Cassell. • Caveat: For the occasional neutral hadron there will be significant fragments but we have a promising technique to find and associate them. G.R.Bower - Santa Cruz LCD Workshop

  10. Isolation of gammas G.R.Bower - Santa Cruz LCD Workshop

  11. Gamma shower characteristics • Compact • Standard cigar shape • Shower initiates in first few EM layers • Shower contained in EM (if deep enough) • Many hits/much energy in first few layers • Accurately point back to IP G.R.Bower - Santa Cruz LCD Workshop

  12. Piminus shower characteristics • Diffuse in shape and energy spread. • Some fragmentation. • Min-I track begins in first layer. • Few hits/little energy until first interaction. G.R.Bower - Santa Cruz LCD Workshop

  13. KOL shower characteristics • Diffuse in shape and energy • Some fragmentation • First hit layer may be very deep • Generally points back at IP G.R.Bower - Santa Cruz LCD Workshop

  14. Fragment shower characteristics • Diffuse in shape and energy • First hit layer may be very deep • Generally do not point back at IP G.R.Bower - Santa Cruz LCD Workshop

  15. Measure cluster properties • Form energy tensor • Energy (shape) eigenvalues • Energy axes • Center of Energy • First and last layers with hits • Energy/# of hits in first N layers G.R.Bower - Santa Cruz LCD Workshop

  16. Superb gamma location resolution Resolve gamma direction to ~1/6 cell size using center of energy of hits G.R.Bower - Santa Cruz LCD Workshop

  17. Separating gammas G.R.Bower - Santa Cruz LCD Workshop

  18. Separating piminuses G.R.Bower - Santa Cruz LCD Workshop

  19. Separating K0Ls G.R.Bower - Santa Cruz LCD Workshop

  20. Summary • Can find gammas with ~100% efficiency and ~few percent fakes. • Can identify most pions without tracking • Can identify majority of K0Ls. • Have only sketched the power of the method. G.R.Bower - Santa Cruz LCD Workshop

  21. Next steps (arbitrary order) • Many details to cross-check. • Reconstruct π0s (dE/E~5%, loc res ~same as π±.) • Associate neutral hadron fragments (improve dE/E). • Work out special cases, eg, charge exchange. • Combine clusters between barrel and endcap. • Use neural net to improve results. • Test on signal events. • Test on physics measurement. • Release tools. G.R.Bower - Santa Cruz LCD Workshop

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