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Direct Gamma Study in NCC

Direct Gamma Study in NCC. Strips distribution for single gamma in geant3 (schematic view). Had some initial meetings with Itaru and Edouard Was very constructive, but we’re all very busy so it would be helpful if we could maybe find a student

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Direct Gamma Study in NCC

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  1. Direct Gamma Study in NCC Strips distribution for single gamma in geant3 (schematic view) • Had some initial meetings with Itaru and Edouard • Was very constructive, but we’re all very busy so it would be helpful if we could maybe find a student • Recap: The problem with direct gamma A_LL and gamma-jet (with gamma in the NCC) is that the background was too high • The isolation cut didn’t seem to be as effective as the central arm. • Without a spectrometer in front and with a thin calorimeter, there is a fundamental limit to how well an isolation cut can work since charged hadrons often just punch through • At relatively low pt (5 GeV) the pi0’s merge and look like gammas – In central arm the partner gamma to the pi0 helps to veto pi0’s but not in the NCC • We will continue to explore the space of cuts, which is multi-dimensional. • More IMPORTANTLY, we want to help Edouard with solving the pi0/gamma separation using the strips. • Fluctuations are very large, up to 3-4 times the signal. • Is the simulation correct, or is there some issue in the implementation? • Is the reconstruction properly done? • If both correct, then it might be that there is a simple algorithm to separate pi0/gamma, but most likely we’ll have to go to a principle components analysis or neural network. x1 y1 x2 y2

  2. VTX, FVTX, NCC in PISA SVX • Was drawing pictures to make sure things were working when the disks went to hell last night • Have some vague idea how to do the tracking • Dave W. et al have been doing studies for optimizing the FVTX design, and have tracking with the mutoo Kalman filter going. • Still a bit rough, eg, they use smeared VTX positions from the pisa hits info. • Put in a GEM for a 50 um hit position in inner radius of NCC, want to extend the acceptance = NEW PHYSICS (should separate this out as a different project). Requires NO HAD section. • Want to study region of good sign determination using full simulation (measuring deflection on NCC is better than sagitta) • Actual background rejection using full simulation • Charged Hadrons • Pi0 dalitz, conversions, pi0+overlapping track • Time scale: hoping for 2-4 weeks

  3. Changes to Standard Pisa Here’s what I did to get PISA working with the VTX, FVTX, and NCC • Used the setup from run7, and taking files from simulation/pisa2000/wrk • Modified pisa.kumac • The CUTS line to have lower cutoffs for particles • Does this affect the reconstruction? • Removed the NOSE entry, changed the PIPE to PIPN • Using Sim3D++ • Enabled SVX and NCC only • Might have to smear vertex according to expected resolution? • Modified phnx.par • None so far… maybe need to change some parameters • sili_endcap_strip_on = 1 to make fvtxgeom.root for offline reco • sili_endcap_config =1 (1=new geom, 2 and up = old geom) • Anything else?

  4. Don’t underestimate the W • RIKEN originally joined RHIC to do the W measurement – paid for south muon arm • Recently, $6.6 million was spent to JUST do the W • $2.3 million for RPC in PHENIX • $2.3 million for Mutr FEE upgrade in PHENIX • $2.0 million for Forward Gem Tracker in STAR • NCC can do W plus MUCH MORE

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