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Photon run analysis. e-. g conversion. Trigger 0.8cmx0.8cm. 180GeV e-. B Y. B Z. g. Photon emitter. Veto counter. 37 m m Cu Foil. Incoming beam is 180GeV electron. Set photon emitter (300 m m Pb) and extra magnet system.
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Photon run analysis e- g conversion Trigger 0.8cmx0.8cm 180GeV e- BY BZ g Photon emitter Veto counter 37mm Cu Foil • Incoming beam is 180GeV electron. • Set photon emitter (300mm Pb) and extra magnet system. • Primary electron bent away from beam line in both directions • Conversion foil (37 mm Cu) in front of Pixel box. LAr front view
MC production Generate a photon with energy according to a function following the photon energy spectrum derived from the data; Generate an electron with energy 180GeV-Eg; Propagate the two particles down the beam line; Photon energy distribution Normalized to unit area data MC Only 1000 event was produced There are some differences … Now trying to fix … GeV
Primary e- e- from cov. e+ from cov. Event display for converted photon case by Atlantis • Cut • Find LArEM calo clusters (n=2,3) • For the trigger electron: • 100 GeV < P (e-) < 160 GeV • 0.45 < h < 0.48 • 0.05 < f < 0.1 • 160 GeV < SE < 190GeV • There is one TRT track associated with e- cluster • Find one TRT track pointing back to 4ly SCT modules. • two • more than 3
Cluster Energy distribution Trigger Electron Energy distribution -- applied cuts 1 and 2 as the previous page All Cluster Energy distribution w/o conv. data Trig. e- g(s) w/ conv. GeV GeV MC
Trigger Electron --- after # of Cluster cut (n=2,3) f h LArEM Cluster position Front View data MC
TRT track Cluster matching xKalman track using only TRT Cluster position – TRTtrack extrapolate pos Not pointing back to SCT ? 1track 2track [rad]
Material data MC
Photon run study for ROME… T.Koffas Conclusions • First look at the CTB photon data quite promising; • Basic tools not all there yet; • + Simulation package modified for photons and validated; + Clustering tools optimized to find nearby EM showers; + TRT track segments successfully matched to e+ e- clusters from conversions. • No software available to track TRT segments back through B-field to Si tracker. This is critical for further progress; without it no possibility to reconstruct e+ e- vertex. • This is an excellent example where the ID and the LAr communities work together in a real combined data analysis environment. There is no additional result after ROME WS
T.Koffas Data looks too large conversion ratio Track finding efficiency is too small We’d like to require SCT information ! Unconverted Converted
2 cl 3 cl
Energy Sum and Photon Energy All Clusters Energy Sum 180GeV - Energy Sum Primary electron momentum 180GeV Photon Energy Spectrum ! GeV GeV Generate a photon with energy according to a function this photon energy spectrum derived from the data --- Now available !