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Maximizing Bs Meson Yield: Improving Decay Selections

In this research summary, Donatella Lucchesi discusses strategies to enhance the Bs meson yield through improved decay selections. Using methods like PID inclusion, neural network discrimination, and new decay modes, the goal is to optimize event selection and boost the overall significance. Additionally, suggestions from A. Heijboer, J. Mulmestadt, and Johannes aim to increase Bs meson significance through innovative strategies like LR cuts and Neural Network selections. Collaboration with B. Casal and K. Anikeev to train NNs, separate signals from backgrounds, and employ mass distribution fitting techniques aid in maximizing the yield. Partially reconstructed B analysis by Jeff Miles and Amanda Deisher is also explored, along with insights into new decay modes by Simone Pagan Griso and V. Tiwari, G. Gomez-Ceballos. The summary highlights plans for increasing events through optimized cuts and the incorporation of new decay modes to elevate Dms significance.

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Maximizing Bs Meson Yield: Improving Decay Selections

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  1. Bs signal selection Donatella Lucchesi University and INFN Padova for Bs Mixing group CDF Collaboration Meeting June 7, 2006

  2. The Blessed Selections: hadronic decays Signal BsDs Ds  BsDs Ds  KK Ds K*0K K*0 K Ds 3 BsDs3 Ds  Ds K*0K Partially reconstructed B mesons B0D- Combinatorial background Donatella Lucchesi

  3. Hadronic Bs decays summary B+D0 ~ 26,000 B0D- ~ 22,000 Donatella Lucchesi

  4. Blessed selection Bs semileptonic Decays BsDslX Ds  KK Ds K*0K K*0 K Ds 3 Total yield: Dsl ~37,000 events Donatella Lucchesi

  5. What can we do to improve it? • Include PID in the selection • Use NN to discriminate signal from background • Add new decay modes Donatella Lucchesi

  6. Including PID in the selections BsDs Ds K*0K K*0 K has reflection from B0D D Kpp when you give K mass to p Standard analysis use D+ veto: |MKpp – MD+|>24 MeV A. Heijboer Donatella Lucchesi

  7. Including PID in the selections Aart proposal: |MKpp – MD+|>18 MeV OR CCL0 19.223.0 Give this to NN A. Heijboer J. Mulmestadt Johannes idea: LR cut event by event increases Ds 1640 In progress the Bs significance evaluation Donatella Lucchesi

  8. Neural Network selections B. Casal, K. Anikeev Use ROOTSNNS v3.0 • Train NN to separate signal from bckg (side bands) • Optimize to maximize • Fit mass distribution using the actual mixing fitter Rectangular cuts NN cuts Increase 33% like adding 78% of more data Donatella Lucchesi

  9. Neural Network selections summary B. Casal, K. Anikeev 57.78/43.30=1.3 improvement A Use wrong charge events as background in the future? Donatella Lucchesi

  10. Partially Reconstructed B Jeff Miles BD, D*p ++0 , D*Dg/p0 treated as hadronic? • Large yields (same order of fully reconstructed) • High k-factor, lose soft g/p0 • Lower S/B Depend on mass Different K def. investigated finally use the standard one Donatella Lucchesi

  11. Partially Reconstructed B Amanda Deisher B0D* -[D0 -] + 5.00<mass<5.35 GeV/c2 Low combinatorial background ct2= 464.6 +14.2–13.5 mm Above 5.17 GeV D*p and D*K Donatella Lucchesi

  12. New Decay Modes Simone Pagan Griso BsDs Ds KsK Ks has reflection from B0D D 3p as for Ds K*0K K*0 K Different topology easy to separate ~270 events 1fb-1 Using PID 16% increase Donatella Lucchesi

  13. Semileptonic decay modes V. Tiwari, G. Gomez-Ceballos • Improve event selection including PID BsDslx: • Dsfp combinatorial bck reduce by factor 2 • Ds K*K yield increased by factor ~2.5 and combinatorial bck reduced by factor 2 • Include l+SVT dataset • Remove the ct* cut Noticeable gain Donatella Lucchesi

  14. Summary • The number of events can be increased by including • new decay modes, partially reconstructed events • and by optimizing cuts. • Plan for the summer: • Include partially reconstructed modes and optimize cuts. • The actual gain on Dms significance will be the • combination of all the effect. • Expected improvements on sA: • 1.3 for the hadronic decay modes cuts optimization • “Something” for semileptonic decays • Under evaluation for adding partially reconstructed • hadronic decay Donatella Lucchesi

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