Selected topics from Belle Something Unique at Belle and New - EPR entanglement - Y(3S) run: Dark Matter Search - B  D*tn (New @FPCP07) - Crab cavity study / Super-KEKB Y.Sakai KEK SLAC seminar 29-May-2007

KEKB / Belle 8 GeV e- x 3.5 GeV e+ KEKB Belle Lpeak = 1.71x1034 ~1 km in diameter Mt. Tsukuba KEKB Belle e+ source Ares RF cavity Belle detector 8 GeV e- x 3.5 GeV e+ Lpeak = 1.71x1034 Integ. Lum. ~700 fb-1

EPR Entanglement Quantum Mechanics: EPR Paradox: Quantum Mechanics: Entangled state  non-separable wave function even for far apart particles can not be a “complete” theory Local realistic theory with “hidden” parameters

Bell Inequality Any Local realistic theory with “hidden” parameters S = |E(a,b)-E(a’,b)| + |E(a,b’)+E(a’,b’)| < 2 (Belle-CHSH Inequality) [Physics 1, 195(1964); PRL 23, 880(1969)] Violation  Reject LRT, Confirm QM Many experiments performed: violation ~established Entangled photons [e.g. G.Weihs et al., PRL 81, 5039(1998)] Entangled Be ions [e.g. M.A.Rowe et al., Nature 409, 791(2001)] _ [CPLEAR, PLB 422, 339(1998) KLOE, PLB 642, 315 (2006)] Also, attempts with K0K0 system

Why Y(4S)  B0B0 System _ One of few coherent systems in HEP Highest energy scale (~10 GeV) breakdown of QM at high energy ? Bell Inequality Test : intrinsically impossible QM to violate B.I. ; x = Dm/G > 2.6  xd = 0.78 Active measurement needed  Flavor measurement via decay reconstruction = passive [.A.Bertlmann et al., PL A332, 355(2004)] Any way to test QM at Y(4S) ?

Flavor Asymmetry (as Dt) Precisely measure Time-dependent decay rate Compare with Non-QM model QM: Same Flavor (B0B0, B0B0): ∝ 1 + cos(DmDt) Opposite Flavor (B0B0) : ∝ 1 - cos(DmDt) _ _ _ OF-SF OF+SF AQM(Dt) = = cos(DmDt)

Non-QM models Local Realism: Pompili & Selleri (PS) (examples) Local Realism: Pompili & Selleri (PS) [EPJ C14,469(2004)] _ _ “elements of reality” = Flavor & mass (BH,BL, BH,BL) random jump of Flavor within pair Spontaneous & immediate Decoherence (SD) [e.g. PR 49,393(1936)] Note) Local realistic model with same A(Dt) as QM is possible [quant-ph/0703206]

Time-dependent Asymmetry

Analysis Method B0  D*ln + Lepton-tag Fully corrected (= true) A(Dt) ~Same as Dm measurement ( high quality lepton-tag only) [PRL,89,251,803(02),PRD 71,972003(05)] Background subtraction Unfolding [SVD method] Fully corrected (= true) A(Dt)  Direct comparison with (any) theories Quantitative Test for non-QM model

Signal Reconstruction background 152M BB 6718 OF 1847 SF

Results & fit with QM Fully corrected A(Dt): fit with QM [quant-ph/0702267, submitted to PRL] Fully corrected A(Dt): fit with QM 152M BB c2 = 5.2 (11 dof) Good ! [ fit including WA Dm = (0.496  0.014) ps-1 (excl. Belle/BaBar)]

Result: SD & PS SD PS c2 = 174 c2 = 31.3 disfavored 13s 152M BB c2 = 174 disfavored 13s over QM c2 = 31.3 disfavored 5.1s over QM Decoherence fraction: l = 0.029  0.057

Y(3S) Run Dark Matter search: Y(3S)  p+p- Y(1S) [ cc] No sensitivity DAMA NaI 3s Region CDMS 04 CDMS 05 WIMPs: good candidate o% antimatter

B ( Y(1S)cc ) ~ 6x10-3 (mc<4.73GeV/c2 ~ mb) W : relic density h : Hubble constant v : 1/20 ~ 1/25 0.1 pb ・ c Wh2 @ <s(ccSM) v > = 0.113  WMAP c q _ c q _ s(ccSM) ~ 18 pb @ s(SM cc ), G(U(1S)cc) = fU2MUs(bbcc) B ( Y(1S)cc ) ~ 6x10-3 (mc<4.73GeV/c2 ~ mb) PRD 72, 103508 (2005) “Invisible quarkonium decays as a sensitive probe of dark matter” Presented by B. McElrath in BNM-I in KEK Sep, 2006 Previous Upper Limit : < 23x10-3 (90% CL) by ARGUS (1986)

Signal of Y(1S)  invisible fixed energy p+ p- p+p- recoil mass forms a peak Y(3S) No signal left in the detector Y(1S) @ 9.46GeV/c2 == mY(1S) Invisible

Y(3S) : best for Y(1S)invisible No signal in detector Y(3S) runs : 2.9 fb-1 (Feb, 2006 : 4days) s~7nb No trigger issue s~4nb S/N~1/8 sISR~0.02nb S/N <1/1000 Energy scan by CLEO

Special: Loose 2-track Trigger Trigger eff. 89.8% (f135) Trig. effic.: monitored by prescaled 1-track Trrig.

Control sample: Y(3S)p+p-Y(1S)[mm] p+ Y(3S) p- 2.9 fb-1 4901.9±71 signals 498K Y(3S)  p+p- Y(1S) 11M Y(3S) p+ p- Y(3S) ~ Signal peak U(1S) m+ m-

Background Suppression + p - ~ Dominant : Two-photon process ~ Pion opening angle in the CMS Vector-sum of transverse momenta of 2 pions in the CMS signal BG Maximum energy deposit in the calorimeter cluster Fisher signal F < -0.7 reject

Backgrounds Y(1S) m+m-, e+e- … (outside of acceptance) p m Two-photon BG recoil mass of p+p- Y(1S) m+m-, e+e- … (outside of acceptance) p m 244 events predictedBr(Y(1S)invisible)=6x10-3

B (Y(1S)invisible) < 2.5x10-3 (90%C.L.) Results Nsignal = 38 ± 39  0 consistent B (Y(1S)invisible) < 2.5x10-3 (90%C.L.) data Fit BG Prediction Br(Y(1S)invisble)=0.6% 2.9 f b-1 at Y(3S) Prediction is disfavored [PRL 98,132001(07)]

Prospect l+l- Disfavored by this result at 90% C.L. Theoretical prediction continue with current condition With super-forward calorimeter & m-detector to reduce peaking BG _ Y(1S)  nn [Veto Y(1S)  ] l+l-

DM search in B  K(*)nn _ SM Signature: K(*) + invisible Another SM: BF(BK ) ~4 x 10-6 (Buchalla, Hiller, Isidori) S h [PRD 63, 014015] Sensitive to New Physics and also Light Dark Matter (mS < 2 GeV/c2) (in loop) [e.g. C.Bird, PRL 93,201803(2004)] Signature: K(*) + invisible

Experimental Method Tag-side: Full reconstruction B- B+ n Signature : Y(4S) B- B+ n K+ Signature : 1 particle + invisible Residual ECL energy EECL ~ 0 535M BB Tag-side: Full reconstruction 641K B  Charged B

Result New ! B(B+  K+nn) < 1.4x10-5 @90% CL 535M BB FPCP07 1.6 < p* < 2.5 GeV/c Nb = 20.0  4.0 Nobs = 10 Preliminary B(B+  K+nn) < 1.4x10-5 @90% CL

Constraint on DM Preliminary

Other B  h(*)nn modes _ New ! FPCP07 Preliminary

Other B  h(*)nn modes _ New ! UL (@90%CL) < 3.4x10-4 < 1.4x10-4 FPCP07 < 1.4x10-4 Preliminary < 1.4x10-5 < 1.6x10-4 < 1.7x10-4 < 2.2x10-4 < 4.4x10-4 < 1.5x10-4 < 5.8x10-5

B  D*tn New ! B decays including t  sensitive to Charged Higgs FPCP07 B decays including t  sensitive to Charged Higgs Always involve > 2 n (Missing E): experimental challenge B  tn : First Evidence ! [Belle, PRL 97, 251802(2006)] B  D* tn : Lepton (t) polarization info. Expected B ~ 1.4% in SM (large) But, large background (D*(**)ln, D*X) [e.g. D.S.Hwang EPJ C14,271(2000)]

B0  D*-t+n :Reconstruction Use detector Hermiticity Full Recon. tag : excellent S/N, but very low efficiency Signal side Tag side Clean signature: D*+lepton “Inclusive B” reconstruction Sub-decay modes: D*-  D0p- t  enn, D0  K+p-/K+p-p0 t  pn, D0  K+p- Sum all the residuals SQ=0, no lepton, SNbaryon=0 _ _ _ -0.25 < DEtag < 0.05 GeV Mtag = [Eb2 – ptag2]1/2 (leptons are too soft : t  mnn not used) MC

Validity Check Tag side “Inclusive” reconstruction Control sample : B0  D*- p+ All tag-side cuts applied

Signal side: Bkg suppression t  enn mode _ D*e n Main background: B  D*e n D**e n other B continuum signal most powerful

Signal side: Bkg suppression t  pn mode Main background: Hadronic B, Continuum M0 > 1.5 M2W – M2M – M2t + M2p > 0 Visible energy: Evis < 8.3 GeV Pion energy: Ep > 0.6 GeV No KL’s in the event : N(KL) = 0 Number of rejected tracks: Nbad < 4 (bad inpact parameters) only two n’s  more kinematic constraint equivalent to |cosqn1n2 | < 1

Signal side: Bkg suppression Before After Bkg. suppression MC MC signal other D*tn modes tenn _ (B =1.4% assumed) D*e/m n D**e/m n other B MC MC c-continuum uds-continuum t  pn peaking part treated as signal

Results B (B0  D*-t+n ) = (2.02  0.36) % First Observation ! Extended ML fit: Signal = Crystal-Ball, Bkg = Argus + peaking Shape params fixed to MC, peaking fixed to expectation t(enn), D(K+p-) t(enn), D(K+p-p0) t(pn), D(K+p-) _ _ Ns=12 +6 -5 Ns=30 +10 -9 Ns=20 +6 -5 Simultaneous fit: Ns=60 +12 -11 6.7s(> 5 w/ sys) First Observation ! B (B0  D*-t+n ) = (2.02  0.36) % +0.40 -0.37 Preliminary

Systematic Error Total 18% for combined BF (*) Preliminary (*) Peaking background 1.2 +1.6 -1.5 5.0 +2.6 -2.2 -1.0 +3.6 -3.2

Cross Checks tenn tpn Fit to signal side variable Preliminary Mtag >5.27 signal background Preliminary cosqn1n2 tpn Mtag >5.275 Mtag <5.26 signal other D*tn background Fit to signal side variable

Checks: Look-back plots Distribution of a variable in signal-box (“N-1” cuts) data signal other D*tn modes background

B (B0  D*-t+n ) = (2.02  0.36) % First Step ! B  D*t+n B  Dt+n +0.40 -0.37 Preliminary Consistent with SM estimations Need more precise measurements & updated SM predictions to obtain useful NP constraint First Step ! B  D*t+n B  Dt+n B+  t+n 95%CL interval (assume fL same) Super B Factory [M.Tanaka Z.Phys. C67,321(1995)]

Prospects: H± sensitivity Super B Factory B g D- t +n B g t +n 50ab-1 50ab-1 5ab-1 Preliminary

Crab Cavity Study Crab Crossing  Head on collision increase Luminosity by ~2 with Crab w/o Crab simulation by K.Ohmi (strong-strong)

Crab cavity Installed Superconducting Crab Cavity Jan-2007: Crab cavity installed (1/ring at Nikko area) 13-Feb-2007: Beam study started Superconducting Crab Cavity HER LER

How works w/ 1 cavity/ring ? IP crab cavity 2 cavities per ring orbits of bunch head and tail

How works w/ 1 cavity/ring ? bunch head bunch tail IP crab cavity crab cavity 1 cavity per ring beam beam orbits of bunch head and tail

Observation of Crabbing ! Crab OFF Crab ON ＋180° 0° Crab ON 0° ＋180° Horizontal HER(1.43MV) LER(0.9MV) Streak camera schematics Hamamatsu C5680

Specific Luminosity

Plan / Goal May-2007 (Golden week): wormed-up once and cooled-down 14-May: Beam operation resumed Study : performance at higher bunch current & at higher total current Beam-bean tune xy > 0.1 Important Step toward Super-KEKB

A few words on Super-KEKB

Consensus in J-HEP community News Consensus in J-HEP community Japanese HEP community reached the following agreement in October 2006 after a long discussion. First priority is to realize ILC, and its R&D should be boosted. On the other hand, flavour physics programs (SuperKEKB, and K and n program at J-PARC) should be carried out as physics programs before ILC (i.e., 2010’s). [M.Yamauchi’s recent talk]

Recommendation by Belle-PAC The committee provided strong endorsement to SuperKEKB in the meeting in April 2007. This is also an important support from the int’l community.

J-PARC n, n construction 2006 2008 2010 2012 2014 2016 2018 2020 J-PARC n, n construction J-PARC R&D J-PARC n, K experiment J-PARC n, m experiment upgrade Budget transfer PF upgrade PF Budget transfer ERL prototype ERL construction experiment KEKB ILC R&D ILC construction experiment Budget transfer Option 1 KEKB ILC R&D ILC construction experiment KEKB upgrade Budget transfer Option 1’ 51

Remarks Letter of Intent for Super-KEKB (Jan-2004) 2008 will be a critical timing for KEKB/SuperKEKB. J-PARC construction will be completed. Belle accumulates 1000/fb. PEP-II/BaBar will be shutdown. It is likely that KEK takes some decision soon. Machine: KEK + contributions from the world Detector: perfectly open to the new collaboration Hope to strengthen collaboration with Western SuperB. Letter of Intent for Super-KEKB (Jan-2004) Progress on Physics cases / Detector / Accelerator Update of LOI in progress welcome to join !

Proposed schedule SuperKEKB ~8×1035 Lpeak~1.5×1034 1.5 - 3×1034 6 ~10B BB and t+t- every year Integrated luminosity (ab-1) 2 yr shutdown for upgrade 4 Crab cavity installation Belle is here. 0.7ab-1 2 2000 2002 2004 2006 2008 2010 2012 2014 Calendar year

Summary Diversity of Analyses & Data [Y(3S/5S)] EPR entanglement Confirmed QM, disfavor PS, DS with >5s Light Dark Matter Search at Y(3S) B (Y(1S)invisible) < 2.5x10-3 (90%C.L.) < Theory Also, searched by B g K(*) n n B g D*- t +n : First Observation ! (5.2s) Crab Cavity installed : study in progress step toward SuperKEKB _ welcome to join !