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, (2001)]

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5 First evidence of ADS B → DK

6 ɸ 3 / ɣ is the least well measured of the unitarity angles. One of methods uses D→K + π -, ADS( ) mode [PRL 78, 3257 (1997), PRD 63, (2001)], One of methods uses D→K + π -, ADS( David Atwood, Isard Dunietz, and Amarjit Soni ) mode [PRL 78, 3257 (1997), PRD 63, (2001)],PRL 78, 3257 (1997)PRD 63, (2001)PRL 78, 3257 (1997)PRD 63, (2001) for which the effect of CP violation can be enhanced by the comparable magnitudes of interfering amplitudes. CKM and color suppressed

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9 R DK measurement is an important Input value for the ɸ 3 angle determination

10 B s →J/Ψ(η, η', f 0 ), D s ( * )+ D s ( * )- (CP-eigenstates)

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17 Difference in widths between two B s -B s mass eigenstates (time-independent)

18 PRL105,201802(2010) 23.6fb -1

19 PRL105,201802(2010) 23.6fb -1

20 PRL105,201802(2010) 23.6fb -1

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

22 X(3915)&& X(4350) in    J/  and  J/  (first observed at Belle) X X: J PC =0 ++,0 -+,2 ++,2 -+,…

23 New peak in    J/  X M: 3914  3  2 MeV,  : 23  MeV, N res = 55  MeV Signif. = 7.7 , Background only fit  e + e - undetected  p t balance required X(3915)→J/ψω in γγ fusion? PRL 104, (2010)

24 Could it be the Z(3930) ( ) ? M: 3914  3  2 MeV,  : 23  MeV, N res = 55  evts M = 3929±5±2 MeV  tot = 29±10±2 MeV Nsig = 64 ± 18 evts   DD    J/  PRL 96, (2006)  c2 ’

25 X(3915)   partial width   B(  J/  ) = 69  eV (J P =0 + )   B(  J/  ) = 21  4 +2 eV (J P =2 + ) For comparison:  :   B( DD ) = 180  50 ± 30 eV If X(3915) = Z(3930) =  c2 ’   0.08 B(  c2 ’   J/  ) B(  c2 ’  DD) Huge for above-open-charm-threshold charmonium

26 Could it be the Y(3930)? B  K  J/  PRL94, M≈3943 ± 17 MeV  ≈ 87 ± 34 MeV B+B+ B0B0 M≈3915 ± 5 MeV  ≈ 33 ± 13 MeV Good overlap with BaBar Y(3930) values X(3915): M: 3914  3  2 MeV,  : MeV, PRL101, PRD82, B+B+ B0B0 M≈3919 ± 5 MeV  ≈ 31 ± 12 MeV

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

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

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

30 e + e – to charm cross sections via ISR

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

32 DDDD * D*D*D*D* DDπ DD * π Λ + c Λ  c Sum of all exclusive contributions Here D=D 0 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

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

34 Exclusive e + e – →D s (*)+ D s (*)- cross-sections A clear peak is seen at threshold near ψ(4040) mass in D s + D s - Two clear peaks are seen at the ψ(4160) and the ψ(4415) masses in D s + D s * - With limited statistics no structure are evident in D s * + D s * - Both the e + e - → D s + D s * - 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. arXiv: (accepted by PRD)

35 Status of SuperKEKB/Belle II

36 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. Further Continuation of Flavour Physics possible at a Super B Factory

37 How to do it? => Upgrade KEKB & Belle

38 e - 7GeV 2.6 A e + 4GeV 3.6 A Target: L = 8x10 35 /cm 2 /s SuperKEK B Colliding bunches Damping ring Low emittance gun Positron source New beam pipe & bellows Belle II New IR TiN-coated beam pipe with antechambers Redesign the lattices of HER & LER to squeeze the emittance Add / modify RF systems for higher beam current New positron target / capture section New superconducting /permanent final focusing quads near the IP Low emittance electrons to inject Low emittance positrons to inject Replace short dipoles with longer ones (LER) SuperKEKB collider The improvement in luminosity is due to the dramatic reduction of beam size (σy ~1 micron -->50 nanometer)

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

40 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 L peak = 2.1x10 34 /cm 2 /s L > 1ab -1

oku yen (M$) for Damping Ring (FY2010) 100 oku yen (M$) for machine: Very Advanced Research Support Program approved for FY : construction, installation 2014(later half): commissioning Funding and Construction

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

43 Summary

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52 All possible two-body decays of ψ(3770), ψ(4040), ψ(4160), ψ(4415) are included Significant effect of interference : model dependent! To reduce model dependence we need to measure exclusive cross sections to open charm final states Resonance shapes Interference term R res =R BW +R int Phys.Lett.B660,315(2008) BES fit to the inclusive R spectrum Parameters of the J PC = 1 – – conventional charmonia ψ(3770), ψ(4040), ψ(4160), ψ(4415) M, Γ tot, Γ ee remain quite uncertain and model dependent

53 How to improve luminosity?

54 Zhen-An Liu Oct 2010 Charm Belle II: Belle Upgrade for the Super KEKB SC solenoid 1.5T New readout and computing systems CsI(Tl) 16X 0 pure CsI (endcap)‏ new electronics (waveform sampling) Aerogel Cherenkov counter + TOF counter → “TOP” + Aerogel RICH Si vtx. det. 4 lyr. DSSD → 2 DEPFET pixel lyrs. + 4 lyr. DSSD  / K L detection 14/15 lyr. RPC+Fe → tile scint. TDR: KEK Report CDC: Tracking + dE/dx small cell + He/C 2 H 6 remove inner lyrs large outer radius faster timing smaller cell →