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New Physics in Rare Decays at Belle

New Physics in Rare Decays at Belle. Toru Iijima Nagoya University. March 4, 2006 KEK Theory Meeting 2006 “Particle Physics Phenomenology”. Conclusion. No New Physics Indication Yet in Rare Decays ! (except for some puzzles). How significant is this fact ? Many peoples expect NP at TeV.

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New Physics in Rare Decays at Belle

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  1. New Physics in Rare Decays at Belle Toru Iijima Nagoya University March 4, 2006 KEK Theory Meeting 2006 “Particle Physics Phenomenology”

  2. Conclusion • No New Physics Indication Yet in Rare Decays ! (except for some puzzles) How significant is this fact ? Many peoples expect NP at TeV.

  3. Talk Outline Search for New Physics in 3rd Gen. Quark (B) and Lepton (t) Decays • Hadronic Penguin decays some puzzles ? • Radiative decays • Electroweak decays • Tauonic decays • Tau decays Lepton flavor violation Figure by Dr.Hayasaka (Nagoya Univ.) At present and future (Super-B)

  4. g Pattern of B Decays • B meson is the heaviest meson in the 3rd generation and its decay has several patterns. • Large b quark mass • Huge top mass • Small Vcb • Non-zero Vub • B meson is an unique lab. To explore flavor mixing and CP violation. • f1, f2, f3 • Vcb, Vub, Vtd • Many loops - box and penguin • W exchange coupled to t

  5. Belle Detector • 7 sub-detectors for precise • Vertexing, • Tracking, • Particle ID, • Calorimetry

  6. 13 countries, 57 institutes, ~400 collaborators Belle Collaboration Seoul National U. Shinshu U. Sungkyunkwan U. U. of Sydney Tata Institute Toho U. Tohoku U. Tohuku Gakuin U. U. of Tokyo Tokyo Inst. of Tech. Tokyo Metropolitan U. Tokyo U. of Agri. and Tech. Toyama Nat’l College U. of Tsukuba Utkal U. VPI Yonsei U. Nagoya U. Nara Women’s U. National Central U. Nat’l Kaoshiung Normal U. National Taiwan U. National United U. Nihon Dental College Niigata U. Osaka U. Osaka City U. Panjab U. Peking U. U. of Pittsburgh Princeton U. Riken Saga U. USTC Aomori U. BINP Chiba U. Chonnam Nat’l U. U. of Cincinnati Ewha Womans U. Frankfurt U. Gyeongsang Nat’l U. U. of Hawaii Hiroshima Tech. IHEP, Beijing IHEP, Moscow IHEP, Vienna ITEP Kanagawa U. KEK Korea U. Krakow Inst. of Nucl. Phys. Kyoto U. Kyungpook Nat’l U. EPF Lausanne Jozef Stefan Inst. / U. of Ljubljana / U. of Maribor U. of Melbourne

  7. The KEKB Collider Belle detector Ares RF cavity e+ source • e- (8.0GeV) × e+ (3.5GeV) • ⇒U(4S) →BB • ⇒Lorentz boost: bg = 0.425 • Finite crossing angle - 11mrad ×2 • Operation since 1999. SCC RF(HER) ARES(LER) Peak luminosity 1.63 x 1034 cm-2s-1 ! Integrated luminosity >560fb-1 The World Highest Luminosity

  8. CESR KEKB Performance Records as of Mar.1,’06 • L peak = 1.63x1034cm-2s-1 • L day = 1182.5pb-1/day • L int = 563.3 (Mar 1,’06) KEKB Lint/month Record = 27.9fb-1

  9. KEKB Upgrade Scenario Lpeak = 1.41034cm-2s-1 Ltot = 330fb-1 (Nov.30, 2004) ~1010 BB/year !! & similar number oft+t- world records ! Major upgrade of KEKB & Belle detector (>1yr shutdown) SuperKEKB Crab cavities Lpeak (cm-2s-1) Lint 5x1034 ~1 ab-1 1.4x1034 330 fb-1 5x1035 ~10 ab-1

  10. Observation of bdg Direct CPV in B0K+p- Observation of Large CPV and evidence of direct CPV in Bp+p- Observation of BK l+ l- Rare Decay Milestone FB asymmetry in BK* l+l- • Successful operation of B factories has enabled us to • Measure the B decays in different patterns. • Measure not only branching fraction, but also more details • CP asymmetry • B+/B0 difference • Distribution (Mx in bsg, AFB in BK*ll) Beginning of B->fK0 saga Large CP Violation in B

  11. 386 x 106 BB hep-ex/0507045 • PID for high momentum K/p. Direct CPV in BKp • Remarkable progress in the B-factory era. CLEO w/ 2.6M BB: [PRD53,1039(1996)]

  12. Possible reasons; • Large EW-penguin (with large phase) • Large color suppressed diagram ? • Or both NP (ex. Z’) ?? No conclusion yet. Kp puzzle ? • Different sign of Acp(K+p-) and Acp(K+p0). • Ratio of branching fraction

  13. bsg/sl+l- • Possible to search for NP in theoretically clean way. • Many observables; • Branching fractions • Mixing induced CPV • Direct CPV • Forward-backward asym. • Ratio of exclusive modes Effective Hamiltonian for bs |C7| by BXsg, Sign of C7, C9, C10 by BXsll M(H+) > 350 GeV already in TYPE II 2HDM

  14. 140fb-1 Eg > 1.8 GeV (M.Nakao @ CKM2005) bsg • BK*g, PRD69,112001 (2004) • 85.0MBB • bsg (inclusive) PRD93,061803 (2004) • 152MBB

  15. w/ constraint from isospin relation bdg • 386M BB • qq background suppression; • Event shape • Decay vertex • Flavor tagging quality Hep-ex/0506079v2 BELLE preprint 2006-5 Submitted to PRL w/ Br(BK*g)

  16. Measurement of B(BXsl+l-) M. Iwasaki et al. submitted to PRD, hep-ex/0503044 • Semi-inclusive technique • Xs is reconstructed from K+ or Ks + 0-4p (at most one p0 is allowed) • MXs < 2.0 GeV • Electron or muon pair • Mll>0.2GeV • Charmonium veto 140/fb data Wrong flavor MXs q2 Theoretical prediction by Ali et al.

  17. C7 = -C7SM C7SM Constraints on Ci from B(BXsl+l-) P.Gambino, U.Haisch and M.Misiak PRL 94 061803 (2005) • Clean prediction for B(BXsll) with 1<q2<6GeV2is available. • Combine Belle and Babar results • Sign of C7 flipped case with SM C9 and C10 value is unlikely. C10NP C10NP Donut : 90% CL allowed region SM C9NP

  18. AFB w/ KK gravition exchange T. Rizzo M=1.5TeV M=1 TeV l- l+ B B q q K* K* l- l+ BK*ll FB Asymmetry • Good electroweak probe for bs loop. • q2 distribution has different pattern depending on sign(C7). Forward Backward q0(the point w/ AFB=0) is sensitive for New Physics SM; q02=(4.2±0.6)GeV2

  19. A10/A7 A9/A7 A10/A7 ＳＭ A9/A7 AFB: Belle Summer ‘05 • 357fb-1 (386M BB) • N(K*ll)=114+-14 (purity 44%) • Unbinned M.L. fit to dG2/dsd(cosq) • 8 event categories • Signal + 3 cross-feed + 4 bkg. • Ali et al’s form factor • Fix |A7| to SM • Float A9/A7 and A10/A7 • Results; w/negative A7 (SM like) w/positive A7 Sign of A9A10 is negative ! See Hep-ex/0508009 & A.Ishikawa’s talk at EPS05

  20. Prospect at Super-B 1000 pseudo experiments w/ SM input values Expected precision @ 5ab-1 dC9 ~ 11% dC10 ~14% d q02/q02 ~11% 5% at 50ab-1

  21. Bl n ; leptonic decays • Proceed via W annihilation in the SM. • Branching fraction is given by • Provide information of fB|Vub| • |Vub| from BXu l n fB cf) Lattice (d~16%) • Br(Bln)/Dmd |Vub| / |Vtd| • Expected branching fraction

  22. Status of Leptonic Decay Search • Results @ Summer’05

  23. Full Reconstruction Method • Fully reconstruct one of the B’s to tag • B production • B flavor/charge • B momentum Decays of interests BXu l n, BK n n BDtn, tn B e- (8GeV) e+(3.5GeV) Υ(4S) p full (0.1~0.3%) reconstruction BDp etc. B Single B meson beam in offline ! Powerful tools for B decays w/ neutrinos

  24. Fully Reconstructed Sample • Belle (253fb-1): 275M BB  2.5x105 B0B0 + 4.2x105 B+B-

  25. Bt n Status (Belle LP05/EPS05) K.Ikado’s talk at EPS05 hep-ex/0507034 • NBB (produced) = 275M • NB+B- (full recon.) = 4.0 x 105 (purity 0.55) • Searched t decay modes • Cover 81% of the t decay • Event selection • Residual ECL energy • Total net charge etc. Obtained Eresidual

  26. Prospect • Will soon reach the SM. • 3s at ~700 fb-1 • 5s at ~2 ab-1 • Expected precision at Super-B • 13% at 5 ab-1 • 7% at 50 ab-1 B t n will be the next major milestone of the Belle mission for rare decay search !

  27. rH H+/W+ t+ tanb/mH Impact to Charged Higgs • Br. with exchange 90%CL excluded region at present 95% CL excluded region at 5ab-1 (if Bobs = BSM)

  28. + exchange c c b b H+ W+ t+ t+ nt nt Charged Higgs in BDtn • Charged Higgs modifies semileptonic decay rates. exchange (SM) Tanaka/ Miura • (the heaviest lepton) is the most sensitive.

  29. BD t n (MC studies) • Use fully reconstructed samples. • T decay modes • Analysis cuts; • Reject events w/ p, KL • Reject D(*)t n contamination • No remaining charged or p0 tracks • ECL residual energy • Angle between two n’s • Missing mass Signal BG

  30. Cont’d • Signal selection efficiency 10.2% 2.6% 26.1% 13.3% • Expectation at 5 / 50 ab-1 for B+ decay 5s observation possible at 1ab-1 • Major background source • Missing charged and g tracks from BD(*) l n X (incl. slow p)

  31. Cont’d Constraint From bsg D(Form-factor) ~5% D(Form-factor) ~15% Present limit From Bt n

  32. Lepton Flavor Violation Quarks have flavor mixing. Neutrino mixing has been found. What about charged leptons ? ? ? (Original figure by Dr. Kuno / Osaka Univ.) B factory is also a tau factory

  33. t3l,lh • Neutral Higgs mediated decay. • Important when MSUSY >> EW scale. tlg/3l,lh tlg • SUSY + Seasaw • Large LFV Br(tmg)=O(10-7~9)

  34. Analysis Method • Signal extraction • Calc. Minv and DE • DE=Erec-Ebeam • Blinded signal region •  Event selection study • Estimate background using sideband data • Open blind and estimate signal yield • Estimate upper limits Signal MC of tmg Signal region Background

  35. tmg tmg/eg at Belle teg 86.3fb-1 data Br<3.9x10-7 at 90%C.L. PLB 613, 20 (2005). Br<3.1x10-7 at 90%C.L. PRL 92, 171892 (2004). • Background: tmnn/enn + ISR (or beam background) • Small amount of mm events in DE>0

  36. t3l • Belle: 87.1fb-1, PLB 598, 103 (2004) • Br<(1.1~3.5)x10-7 at 90%C.L. • Background: low level • qq for DE<0, QED(mm or Bhabha) for DE>0 Signal region

  37. B.R. Summary • Br < O(10-6) in PDG (by CLEO) •  Br < O(10-7) by Belle and BaBar

  38. Future prospect • Super B-factory : >10 times more data • B.R. sensitivity: ~1/n for negligible BG case ~1/n for BG dominating modes

  39. Future prospect (2) • Possible sensitivity with Super B-factory • Red band for 5~10ab-1 Super B-factory

  40. Super-B Present Belle Gaugino mass = 200GeV Constraint to NP tlg • SUSY + Seasaw • Large LFV Br(tmg)=O(10-7~9) • t3l,lh • Neutral Higgs mediated decay. • Important when MSUSY >> EW scale.

  41. Interplay between B and t J.Hisano @ Tau04 Workshop, Nara, Nov, 2004. J.Hisano, Y.Shimizu PLB565(2003)183.

  42. Concluding Remarks • No New Physics Indication Yet ! • Need more luminosity. This year: Crab cavity installation Stay tuned ! Future: Super-KEKB

  43. Future • Let’s discuss together • Role of flavor physics • Synergy with LHC NP evidence Flavor Phys (ex. Super-B) LHC 1. We will be busy! Scenario of studies ? 2. Scenario of studies ? 3. How significant is the null result at F.P. to constrain NP model. 4. Where do we go ?

  44. CERN Flavor WS • Discuss synergy between Flavor Physics (B/C/K/t/m etc.) and LHC. • Bench mark model & parameters for studies. • Nov. 7-10, 2005 • Feb. 6-8, 2006 • May.15-17, 2006 • Final report at 2006/end or 2007/beg. Let’s discuss together !

  45. Backup

  46. Radiative Decays • Inclusive Br(bsg) |C7|, SF for |Vub| • BK*g isospin asymmetry (D+-) sign of C7 • Mixing induced CPV • Direct CPV in BXsg • BXdg Summary by M.Nakao 1st Super-B workshop at Hawaii

  47. B0KSp0g tCPV: Belle Summer ‘05 • 386MBB • M(Ksp0) < 1.8GeV/c2 • NP effect is independent of the resonance structure. • Two M(Ksp0) regions(MR1:0.8-1.0GeV/c2 / MR2: <1.8GeV/c2) • 70+-11 (45+-11) events in MR1(2). • Atwood, Gershon, Hazumi, Soni, • PRD71, 076003 (2005) Result S= +0.08 ±0.41 ±0.10 A= +0.12±0.27±0.10 Good tag (0.5<r<1.0) Present Belle (stat./syst.) 5ab-1 50ab-1 Acpmix(BK*g, K*Ksp0) 0.41 / 0.10 0.14 0.04 Acpdir(BXsg) 0.051 / 0.038 0.011 0.005

  48. Acp(BXsg) vs SUSY models 5ab-1 50ab-1 Mixing CPV Direct CPV U(2) tanb=30 mSUGURA tanb=30 U(2) tanb=30 mSUGURA tanb=30 Acpdir Acpmix SU(5)+nR tanb=30 non-degenerate SU(5)+nR tanb=30 degenerate SU(5)+nR tanb=30 non-degenerate SU(5)+nR tanb=30 degenerate T. Goto, Y.Okada, Y.Shimizu,T.Shindou, M.Tanaka hep-ph/0306093, also in SuperKEKB LoI

  49. Form factor error Constraint to Charged Higgs • Once branching fraction is measured, we can constrain R. M.Tanaka, Z.Phys. C67 (1995) 321 r can be determined experimentally by B semiletonic decays at 5ab-1

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