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Belle “Engineering Run” on the Υ (3S)

Belle “Engineering Run” on the Υ (3S). S. L. Olsen. The Cosmic Mystery-Pie. o% antimatter. WIMPs (Weakly-Interacting-Massive-Particles) are good dark matter candidates. DAMA NaI 3 s Region. c. c. N’. b. CDMS 04. CDMS 05. Upper Limits from Direct Measurements.

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Belle “Engineering Run” on the Υ (3S)

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  1. Belle “Engineering Run” on the Υ(3S) S. L. Olsen

  2. The Cosmic Mystery-Pie o% antimatter WIMPs (Weakly-Interacting-Massive-Particles) are good dark matter candidates

  3. DAMA NaI 3s Region c c N’ b CDMS 04 CDMS 05 Upper Limits from Direct Measurements 90% CL upper limits assuming standard halo A2 scaling Predictions: Ellis & Olive, Baltz & Gondolo, Mandic & all c N c b Direct measurements have no sensitivity for ~GeV mass region LHC will reach ~TeV mass region Who will search ~GeV mass region ?

  4. Possibility of Dark Matter Search in B-factory PRD 72, 103508 (2005) Br( Υ(1S)cc ) ~ 0.0041 (mc<4.73GeV/c2) Υ(3S)gISR Υ(3S)  p+p-Υ(1S), Υ(1S) invisible However … Two-photon backgrounds are quite high … Hard to reach Br ~ O(0.001)

  5. Idea to improve S/N ratio s(e+e- Υ(3S)gISR ) ~ 0.02 nb s(e+e- Υ(3S)) ~ 3.3 nb S/N ratio x150 Energy scan in CLEO

  6. Expected Sensitivity on Y(3S) run Y(3S) run w/o TRG modification Y(3S) run x 4 trigger efficiency Y(4S) run 460 /fb 90 %C.L Theory prediction *) Syst. error is not considered We took engineering data on the Υ(3S) to check:  sensitivity with different trigger logic  KEKB performance at lower Ecm  sensitivity for other physics topics trigger conditions were too tight for Υ(3S)p+p-nothing looser triggers were needed for the required sensitivity

  7. Belle took data for 4.5 days(end of Feb, 2006) CLEO ~3.3nb---- Energy scan ~ 4hours We set E(4S)-223.6 MeV ~ 3 /fb on Υ(3S) resonance ~0.25 /fb on; 30MeV below 3S

  8. Trigger logic was optimized for DM channel Control sample data Υ(3S)  Υ(1S)p+p- Υ(1S)  m+m- Eff. depends on opening angle 4 times efficiency gain is expected - loose opening angle cut 135 45 degree - loose pt cut pt>350 MeV for both tracks  for one (or both) track opening angle (degree) p+ p- y x

  9. Trigger Rate Trigger rate was rather higher than usual condition (~460Hz) Trigger Rate (Hz)

  10. Last BGM slide by Ito-san w/o Event Builder Upgrade w/ Event Builder Upgrade Belle Dead Time (%) Trigger Rate (Hz) DAQ Dead time was consistent with expectation We confirm great advantage of event builder upgrade (2005 summer) However, there were frequent DAQ errors  remaining subject …

  11. Υ(3S)p+p-Υ(1S); Υ(1S)m+m-with 137 pb-1(~4% of total) 197 evts

  12. applications

  13. Summary • Υ(1S)invisible is sensitive for light dark-matter • Υ(3S)  p+p-Υ(1S)invisible • direct searches have no sensitivity ~GeV mass region • We tookΥ(3S) engineering runs for 4.5 days • ~3 /fb (~10M evts) on Υ(3S); ~0.25 /fb off-resonance) • world’s largest Υ(3S) data sample • Offline analysis of Υ(1S) invisible is in progress • Only a few other analyses are currently planned • interested parties encouraged to apply • Also have ~20 /fb data sample @ theΥ(5S) • also the world’s largest Υ(5S) sample (by far!)

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