Engineering Runs on Y(3S)

The Cosmic Mystery-Pie

o% antimatter

WIMPs (Weakly-Interacting-Massive-Particles) are good dark matter candidates

DAMA NaI 3Region

CDMS 04

CDMS 05

90% CL upper limits assuming standard halo A2 scaling

Upper Limits from Direct Measurements

Predictions: Ellis & Olive, Baltz & Gondolo, Mandic & all

Direct measurements have no sensitivity for ~GeV mass regionLHC will reach ~TeV mass regionWho will search ~GeV mass region ?

Possibility of Dark Matter Search in B-factory

PRD 72, 103508 (2005)

Br( Y(1S) ) ~ 0.0041 (m<4.73GeV/c2)

Y(3S)ISR

Y(3S) +-Y(1S), Y(1S) invisibleHowever …Two-photon backgrounds are quite high …Hard to reach Br ~ O(0.001)

Idea to improve S/N ratio

(e+e- Y(3S)ISR ) ~ 0.02 nb

(e+e- Y(3S)) ~ 3 nb

S/N ratio x150

Energy scan in CLEO

Y(3S) run w/o TRG modification

Expected Sensitivity on Y(3S) run

Current trigger condition is too tight for this channelLoose trigger condition gives large the sensitivity

*) Syst. error is not considered

Y(4S) run460 /fb

Theory prediction

90 %C.L

Y(3S) run w/o TRG modification

Expected Sensitivity on Y(3S) run

Current trigger condition is too tight for this channelLoose trigger condition gives large the sensitivity

*) Syst. error is not considered

Y(4S) run460 /fb

Theory prediction

90 %C.L

Y(3S) run x 4 trigger efficiency

We took engineering data taking on Y(3S) to check the sensitivity with different trigger logic to check the capability of DAQ with such trigger to check the sensitivity for other physics topics

We took data for 4.5 days(end of Feb, 2006)

Energy scan ~ 4hoursWe set E(4S)-223.6 MeV~ 3 /fb on 3S resonance ~0.25 /fb on 30MeV below 3S

CLEO

3 times hadrons~0.47 on Y(4S)~0.33 off-resonance

Trigger logic was optimized for DM channel

Control sample data(3S) (1S)(1S) Eff. depends on opening angle

opening angle (degree) 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

x

y

Trigger RateT

rig

ger

Rat

e (H

z)

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

w/o Event Builder

Upgrade

w/Event BuilderUpgrade

Last BGM slide by Ito-san

DAQB

elle

Dea

d T

ime

(%)

Trigger Rate (Hz)

Dead time was consistent with expectationWe confirm great advantage of event builder upgrade (2005 summer)However, there were frequent DAQ errors remaining subject …

Summary• Invisible decay of Y(1S) is sensitive for light Dark

– Y(3S) p+p-Y(1S)invisible

– Direct search has no sensitivity ~GeV mass region

• We took Y(3S) engineering runs for 4.5 days– (~3 /fb on-reso. , ~0.25 /fb off-reso.)

• Trigger was optimized for DM channel loose opening angle, pt-cutquite high trigger rateDAQ capability was checkedFrequent fatal errors are next subject…

• Offline analysis are on going