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Recent results from Belle and Status of SuperKEKB/Belle II

Recent results from Belle and Status of SuperKEKB/Belle II. Chengping Shen Univ. of Hawaii, Belle collaboration. Outline. David A twood, Isard D unietz, and Amarjit S oni [ PRL 78, 3257 (1997), PRD 63, 036005 (2001)]. First evidence of ADS B → DK. CKM and color suppressed.

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Recent results from Belle and Status of SuperKEKB/Belle II

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  1. Recent results from Belle and Status of SuperKEKB/Belle II Chengping Shen Univ. of Hawaii, Belle collaboration

  2. Outline David Atwood, Isard Dunietz, and Amarjit Soni [PRL 78, 3257 (1997), PRD 63, 036005 (2001)]

  3. First evidence of ADS B → DK

  4. CKM and color suppressed ɸ3/ɣ is the least well measured of the unitarity angles. One of methods uses D→K+π-, ADS(David Atwood, Isard Dunietz, and Amarjit Soni ) mode [PRL 78, 3257 (1997), PRD 63, 036005 (2001)], for which the effect of CP violation can be enhanced by the comparable magnitudes of interfering amplitudes.

  5. RDK measurement is an important Input value for the ɸ3 angle determination

  6. Bs →J/Ψ(η, η', f0), Ds(*)+Ds(*)- (CP-eigenstates)

  7. Difference in widths between two Bs-Bs mass eigenstates (time-independent)

  8. PRL105,201802(2010) 23.6fb-1

  9. PRL105,201802(2010) 23.6fb-1

  10. PRL105,201802(2010) 23.6fb-1

  11. (indirect measurement) CDF and D0 measured Delta Gamma using the time distributions of Bs decays. This has no model dependence. direct measurements

  12. X(3915)&& X(4350)in ggwJ/y and J/(first observed at Belle) X X: JPC=0++,0-+,2++,2-+,…

  13. New peak inggwJ/y X X(3915)→J/ψω in γγ fusion? M: 3914  3  2 MeV, G: 23  10 +2 MeV, Nres = 55  14 +2 MeV Signif. = 7.7s, • e+e- undetected • pt balance required -8 -14 Background only fit PRL 104, 092001 (2010)

  14. Could it be the Z(3930) ( ) ? cc2’ M = 3929±5±2 MeV Gtot = 29±10±2 MeV Nsig = 64 ± 18 evts gg DD PRL 96, 082003 (2006) M: 3914  3  2 MeV, G: 23  10 +2 MeV, Nres = 55  14 +2evts gg J/ -8 -14

  15. X(3915) Gggpartial width GggB(wJ/y) = 69  16 +7eV (JP=0+) -18 GggB(wJ/y) = 21  4 +2 eV (JP=2+) -5 For comparison: Z(3930): GggB(DD) = 180  50±30 eV B(cc2’wJ/y) B(cc2’DD) If X(3915) = Z(3930) = cc2’  0.08 Huge for above-open-charm-threshold charmonium

  16. Could it be the Y(3930)? PRD82, 011101 PRL101, 082001 BKwJ/y B+ B+ PRL94, 182002 B0 B0 M≈3943± 17 MeV G≈ 87± 34 MeV M≈3915± 5 MeV G≈ 33± 13 MeV M≈3919± 5 MeV G≈ 31± 12 MeV X(3915): M: 3914  3  2 MeV, G: MeV, Good overlap with BaBar Y(3930) values

  17. The CDF Y(4140)J/ K. Yi ICHEP 2010 B+ K+f J/y D*sD*s molecule? [cscs] tetraquark? a 2nd one at m=4275 MeV? If B(B+K+ Y4140) B(B+K+J/y) m = MeV/c2 B(Y4140fJ/y) 10% G(Y4140fJ/y) 1.2 MeV

  18. Searched for Y(4140) in J/ • No Y(4140) (efficiency is very low ~0.3%) • White histograms are data, the shaded are normalized  and J/ sidebands events • A few events accumulate at 4.35 GeV in both J/ee &  modes • Our upper limits disfavor the scenario Y(4140) being a Ds*+ Ds*-molecule with JPC=0++ or 2++ [PRD80, 054019,2009] 825 fb-1 JP=0+: ΓγγBr(Y(4140)) →J/) < 39 eV @ 90% C.L. JP=2+: ΓγγBr(Y(4140)) →J/) < 5.7 eV @ 90% C.L.

  19. Fit to J/ invariant mass • M= MeV/c2 • Γ= MeV/c2 • N (X(4350))= S.S.=3.9, const. bkg S.S.=3.2, linear bkg 825 fb-1 PRL 104, 112004 (2010) • Excited P-wave charmonium? • Tetraquark? Fl. Stancu, arXiv: 0906.2485 • D*sD*s0 molecule at 4.34±0.09 GeV? • J.R.Zhang et al., arXiv:0905.4672 JP=0+: ΓγγBr(X(4350)) →J/) = eV JP=2+: ΓγγBr(X(4350)) →J/) = eV

  20. e+e– to charm cross sections via ISR

  21. e+ c c e+ e+ e- e-  Use ISR to measure open charm exclusive final states s=(Ecm-E)2-p2 ISR at B factories • Quantum numbers of final states are fixed JPC = 1– – • Continuous ISR spectrum: • access to the whole √s interval • emsuppression compensated by huge luminosity • comparable sensitivity to energy scan (CLEOc, BES)

  22. DD DD* D*D* DDπ DD*π Λ+c Λc Sum of all exclusive contributions • Here D=D0 or D+ . The same for D* • Only small room for unaccounted contributions • Charm strange final states • Limited inclusive data above 4.5 GeV • Charm baryons final states

  23. not reconstructed if undetectable e+ reconstructed e+ Ds(*)- e– s=E2cm-2EγEcm Ds(*)+ e+e–→Ds(*)+Ds(*)- via ISR with full reconstruction γ • Full reconstruction of hadronic part • ISR photon detection is not required • but used if it is in the detector acceptance • Translate measured Ds(*)+Ds(*)- mass spectrum to cross section • Ds+ are reconstructed using six decay modes: KsK+,K-K+π+, KsK- π+π+, η π+ and η’ π+

  24. A clear peak is seen at threshold near ψ(4040) mass in Ds+Ds- Two clear peaks are seen at the ψ(4160) and the ψ(4415) masses in Ds+Ds*- With limited statistics no structure are evident in Ds*+Ds*- Both the e+e-→ Ds+Ds*- cross section and R ratio exhibit an obvious dip near the Y(4260) mass, similar to what is seen in e+e-→D*D* and in the total cross section for charm production. Exclusive e+e–→Ds(*)+Ds(*)-cross-sections arXiv:1011.4397 (accepted by PRD)

  25. Status of SuperKEKB/Belle II

  26. Further Continuation of Flavour Physics possible at a Super B Factory • What is the next experimental step? Precision measurements • Much larger sample needed for this purposeSuper B factory • Hopefully new phenomena might be seen: • CPV in B and D decays from the physics outside the CKM scheme. • Lepton flavour violations in  decays. • Physics models can be identified (if new effects are observed) or new ones can be constrained (if nothing is seen). • Physics motivation is independent of LHC. • If LHC finds NP, precision flavour physics is compulsory. • If LHC finds no NP, high statistics B/ decays would be a unique way to search for the physics far beyond the TeV scale.

  27. How to do it? => Upgrade KEKB & Belle

  28. SuperKEKB collider e+ 4GeV 3.6 A Colliding bunches Belle II New IR e- 7GeV 2.6 A New superconducting /permanent final focusing quads near the IP SuperKEKB New beam pipe & bellows Replace short dipoles with longer ones (LER) Add / modify RF systems for higher beam current Low emittance positrons to inject Positron source Damping ring Redesign the lattices of HER & LER to squeeze the emittance New positron target / capture section Low emittance gun TiN-coated beam pipe with antechambers Low emittance electrons to inject The improvement in luminosity is due to the dramatic reduction of beam size (σy ~1 micron -->50 nanometer) Target: L = 8x1035/cm2/s

  29. Plan and Expectation with SuperKEKB Milestone of SuperKEKB We will reach 50 ab-1 in 2020~2021. 9 month/year 20 days/month Integrated Luminosity (ab-1) Commissioning starts In later half of 2014 Peak Luminosity (cm-2s-1) Shutdown for upgrade 21-24 Oct 2010 Charm2010

  30. Status: Termination of KEKB on June 30, 2010 marked the start of SuperKEKB/BelleII First physics run on June 2, 1999 Last physics run on June 30, 2010 Lpeak = 2.1x1034/cm2/s L > 1ab-1

  31. Funding and Construction 5.8 oku yen (M$) for Damping Ring (FY2010) 100 oku yen (M$) for machine:Very Advanced Research Support Program approved for FY2010-2012 2010-2013: construction, installation 2014(later half): commissioning 41

  32. New Collaboration (Belle II) • Belle II is a new international collaboration • 360 members - 57 institutions • Regular collaboration meetings • TDR (Technical Design Report) has been published (arXiv:1011.0352)

  33. Summary

  34. backup

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