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Comparison of the p + p - g signal selection with past results

Comparison of the p + p - g signal selection with past results. C. Di Donato, M. Jacewicz. Signal/Background. X-section  [  b]: 2.04  10 -3 9.87  10 -3 0.30  10 -3 0. 46 0.14  10 -3. Reaction:             0  e  e        0

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Comparison of the p + p - g signal selection with past results

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  1. Comparison of the p+p-g signal selection with past results C. Di Donato, M. Jacewicz

  2. Signal/Background X-section  [b]: 2.04  10-3 9.87  10-3 0.30  10-3 0. 46 0.14  10-3 Reaction:    0  ee 0 ee0 • Most frequent charged  decays: • BR() = (22.73±0.28)  10-2 • BR(0) = (4.60±0.16)  10-2 • BR(ee) = (6.8±0. 8)  10-3

  3. New VS Old RAD Stream 2 pnc 1 charged vertex rxy<4cm & |z|<8cm 2 tracks balanced charge Kinematic fit: quadrimomentum conservation with 2 clusters compatible with photon hypothesys Cut on M(recoil) to reject +-0 RAD + RPI + KPM At least 2pnc one of them with Eg>250MeV Two tracks with balanced charge and closest to IP using info at pca 2 neutral cluster in time, with most energetic assumed to originate from  Eg(recoil) calculated from 2 body kinematics  Using eta decay kinematic we correct Eg(h) Cut on Eg(h) to reject background

  4. Analysis versus EVCL • Stream correlation for MC charged RAD investigated: run RAD, RPI & RAD, KPM & RAD & RPI ALL RAD RPI KPM

  5. Using new approach MC 2005: All Phys, runs 34410-34499 (12.7pb-1) Only RAD stream

  6. Track Selection VS Vertex Selection • Best Results from track selection using PCA at IP parameters Vertex Track

  7. Event Signature in RAD Mh Mppg (MeV) Preselection and Event Signature OLD: 2 PNC + VTX e=46% Lint(2001) =95.7pb-1 NEW: 2 PNC + 2 TRK e=49% Lint(MC2005) =12.7pb-1

  8. Signal/background

  9. Signal/background

  10. Signal/background Opening angle between calculated  and selected neutral cluster from pnc, rejects background

  11. Signal Selection

  12. Two photons invariant mass Measured ALL 0 0  ALL 0 0  Corrected Before cuts ALL 0 0  ALL 0 0  Measured Corrected After cuts

  13. Two photons invariant mass corrected variables ALL 0 0  100 MeV < M< 170 MeV ()=39% Bg=1%

  14. Control Sample 0

  15. Control Sample 0 ALL 0 0 BG 

  16. Outlooks • Analysis in RAD stream: • Ilaria’s cuts to reject BG • Evaluate efficiency • Control sample • Analysis in KPM+RPI stream: • Evaluate efficiency

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