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Results from B- factories

Results from B- factories. ByungGu Cheon Sungkyunkwan University. Presented at ACFA LC workshop (15-17 Dec 2003, TIFR, Mumbai, India). outline. Belle and BaBar CP violation in B meson decays New Physics search in B factory Toward >10 35 lumonosity era.

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Results from B- factories

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  1. Results from B-factories ByungGu Cheon Sungkyunkwan University Presented at ACFA LC workshop (15-17 Dec 2003, TIFR, Mumbai, India)

  2. outline • Belle and BaBar • CP violation in B meson decays • New Physicssearch in B factory • Toward >1035 lumonosity era Most of physics results shown today are based on LP03 presentations !

  3. Luminosity frontier colliders Records by summer 2003, now data taking again!

  4. Detectors Belle BaBar • Typical design : • SVD+CDC+PID+ECL+KLM • PID : TOF+ACC vs DIRC

  5. If either S or A is non-zero, B fCP has CP asymmetry. Time-dependent CP violation Mixing-induced CPV param. Direct CPV param.

  6. CP eigenstates (xf CP eigenvalue)

  7. How to measure CP violation? BCP e-: 8.0 GeV e+: 3.5 GeV fCP e- e+ ¡(4S) bg ~ 0.425 DzcbgtB ~ 200 mm Btag Flavor tag Dz • 4 steps toward theCPviolation measurement • ReconstructBfCPdecays • Determine the flavor ofBtag • Measure proper-time interval :Dt • Evaluate asymmetry from the obtainedDtdistributions

  8. B0 (cc)KS vs. (ss)KS 2716 signals 68signals

  9. sin2f1 : bccs

  10. sin2f1 : bsss Theoretically cleanest example : First Indication of New Physics in quark sector

  11. Summary of sin2f1 Sbs: 3.1s away from Sbc 2.1s difference in Sbs(fKs) NP? Stat. Fluctuation? more data: interesting Sbc 2.1s Sbs 2003 2006

  12. New Physics search in B decays squark d b d b b s squark Tree diagrams: New Physics(SUSY) effect ~negligible Loop diagrams: W, heavy quark loop in the SM Effect of NP particles in loop can be visible Processes with loop diagrams only  sensitive to NP Aobs = ASM + ANP Penguin deviation from ASM only |Aobs|  Branching fraction phase(ASM/ANP)  CP asymm. Box Many modes/ways in B-factory !

  13. B/t decays for NP search • New CPV phase in Penguin : Time-dependent CPV • Radiative & EW Penguin : b sg, b sl+l- • LFV t decays : tmg, tmh • DCPV in ffK-hc(ff)K interference(b s Penguin) • b snn, B  ln, l+l- , B  D(*)tn • NP in B0-mixing by detailed (r,h) consistency study • and so on…

  14. NP particles?! B  K*(892)g 78fb-1 decay through Penguin only B(B0K*0g) = (4.09 0.21 0.19) B(B+K*+g) = (4.40 0.33 0.24) x10-5 Isospin asymmetry: D0+ = [G(B0)-G(B+)]/[G(B0)+G(B+)] = +0.003 0.045 0.018 [SM: D0+ >0  sign of Re(C6/C7)] ACP = -0.0010.044 0.008 (SM: |ACP| < 1%) sensitive to NP !

  15. BXsg,K*g Inclusive No deviation from the SM Need reducing errors: theory : NLO to NNLO exp. : lower Eg (more data) Exclusive All measurements agree. Need better theor. precision: debate on BK* form facor

  16. b  s g

  17. b  s l+l- Penguin + Box diagram contribution Additional dimension: Mass(l+l-) [l+l- angle g helicity] More opportunity to distinguish New Physics effect/models (exclusive) BKl+l- : first observed by Belle @29fb-1(LP 2001) BK*l+l- : first evidence by BaBar@81fb-1(EPS03) Now Belle/BaBar updated with 140fb-1/113fb-1 data !

  18. B  Xsl+l- Inclusive bsl+l- : better theoretical prediction 60 fb-1 [PRL 90, 021801 (2003)] Semi-inclusive analysis (pseudo-reconstruction) Xs=(K+ or Ks)+0~4p(0,1 p0) (covers 81%) MXs<2.1 GeV/c2 60.1 13.9 ev. 5.4s hep-ex/0306018(BaBar) w/ 81fb-1

  19. Mll and MXs distributions Mass distribution SM prediction Model by A.Ali et al. [PRD 66, 034002(2002)] observed Mllspectrum observed M(Xs) spectrum SM acceptance corrected ~ consistent with SM prediction M l l (GeV/c2) M(Xs) (GeV/c2)

  20. b s l+l- [A.Ali, et al. PRD 64, 074024(2000)] BF Started to see signals (consistent with SM) K*mm More data towards SUSY Mmm Afb K*mm Mmm

  21. Rare B decays

  22. If we’ve more data…

  23. t decays B-factory : also excellent t-factory (~1M t-pairs/fb-1) Promising mode to see New Physics effect t  mg decay forbidden in the SM (very small even with n mixing) SUSY, L-R symmetry model … allow LFV decays SUSY particles Br(tmg) ~ 10-9~-7 [~ 105-6xBr(m eg)]

  24. Search fort  mg Reconstruction DE = Em+Eg -Ebeam Minv = Mass(mg) (78.5M t-pairs) Signal MC CM CM CM 2D unbin’d extended Max. Likelihood fit Result：s<5.1 @90%CL sideband 5s region (esel= 0.11) Br(t  mg )< 3.1x10-7 @90%CL hep-ex/0310029

  25. t  mg (New)

  26. The mystery meson

  27. ILER=20A Constraint: 48GeV x 3.5GeV 4wall plug pwr.<100MW 4crossing angle<30mrad L~1036 ILER=9.4A Increase RF L=2x1035 One year shutdown to: 4install ante chamber 4increase RF 4modify IR ILER=1.5A L=2x1034 Present KEKB L=1034 Crab crossing ILER=1.5A ∫Ldt =350fb-1 2002 03 04 05 06 07 08 09 10 11 KEK B-factory upgrade strategy L=5 1035 (New) 1999-2003 data set (158fb-1) in 1 week

  28. Some words on Super-B project HL05 workshop @Izu • Optimal scenario: NP found at Tevatron/LHC/LC • Super-B to measure its parameters(flavor mixing, CPV,…) precisely. If NP is SUSY, the interest is in its breaking mechanism. Even if no deviation from SM is found, that is very interesting. (No effect of existing particles?) • Intriguing scenario: deviation from SM found in flavor physics (has already started?) • Super-B to measure it more precisely. • Frustrating scenario: SM looks fine even after LHC/LC • Super-B to search for NP, competing with LHC/LC.

  29. Super B Factory Workshop in Hawaii January 19-22, 2004 East-west Center, Honolulu To discuss physics, accelerator and detector assuming NBB, Nt>1billion, L>1035.

  30. Comparsion with the previous results Belle ? BaBar

  31. K p1 g p2 Kpp c.m.s B  Kppg New possibility to measure g helicity or CPV (more sensitive to NP than Br) SM: g ~left-handed ~ no Time-dependent CPV Sizable CPV SUSY,LR-symm.: right-handed g Helicity : B  Xs g, Xs  3-body [K1(1400)  Kpp] [M.Gronau et al., PRL, 88, 5(2002)] CPV: B0 K1(1270)g Ksr0 Ksp+p- [D.Atwood et al., PRL, 79, 185(1997)]

  32. B(B+K+p+p-g) = (24 5 )x10-6 +4 -2 B  Kppg ∫L dt = 29 fb-1 [PRL 89, 231801(2002)] First Observation ! Bump : MKpp=1.3~1.4 GeV K*(892), r peaks seen Need more data to extract K1(1270),K1(1400) A big step towards g-helicity meas., Time-dep CPV !

  33. m g tag t m t (g) n Search for t  mg Signature(topology): m + g [signal side] + opposite sign track (not m: ) (+ g’s) [tag side] pmiss > 0.4GeV(n) Mmiss ~ 0

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