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Interference Effects in D Meson Decays

Interference Effects in D Meson Decays. D. Cinabro Wayne State University FPCP 2006, 12 April. Why Interference Effects?. Provide unique information Phases and amplitudes are otherwise inaccessible

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Interference Effects in D Meson Decays

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  1. Interference Effects in D Meson Decays D. Cinabro Wayne State University FPCP 2006, 12 April

  2. Why Interference Effects? • Provide unique information • Phases and amplitudes are otherwise inaccessible • Need these to extract fundamental parameters (CKM elements for example) from other measurements • Challenge and input for QCD

  3. Outline New results (since summer 2005) are thin • DKK0 Dalitz analysis for DKK* strong phase from CLEO-III • D3 Dalitz analysis from CLEO-c • Quantum Correlations in D0D0 decays from the ’’ for phases and mixing parameters from CLEO-c _

  4. CLEO Data Sets • CLEO-III data on (4S), 9/fb with charm produced in continuum or from B decay • CLEO-c data on the ’’, 281/pb, which corresponds to 1.4M D pairs.

  5. CLEOc Detector Venerable CsI Calorimeter 2.2% resolution on 1 GeV photon, 5% on 100 MeV, p/p = 0.6% at 1 GeV, RICH particle ID

  6. CLEO-III: DKK0 • Motivation is to extract strong phase difference in DK*K • See Grossman, Ligeti, and Soffer (PRD 67(2003)07130) and Rosner and Suprun (PRD68(2003)054010) for how this helps measure CKM  (3) in charged B decay

  7. DKK0: Charged D* Tag • 600 Signal S:B=4:1, Soft  tag gives D0 flavor

  8. DKK0 • Both charges of K* and  contributions clearly visible • Interference between K*’s is also clear

  9. DKK0

  10. CLEO-III: DKK0 • Preliminary • DK*K = 332o±8o±11o, large interference • |A(DK*-K+)|/ |A(DK*+K-)|= 0.52±0.05±0.04 • Precision limited by non-K* contributions to the decays • Observed branching fractions consistent with previous measurements

  11. CLEO-c: D3 Dalitz First time doing a Dalitz analysis that has been done by E791 and FOCUS (previously concentrated on modes with 0) 2600 signal on S:B of 2:1 (E791 1200, FOCUS 1500) Mbc = Ebeam2 + p32, E = Ebeam - E3 __________

  12. D3 Dalitz • Symmetry under interchange of like-sign pions • Dalitz analysis on high mass versus low mass unlike-sign pion combinations • Big vertical stripe is Ks

  13. D3 Dalitz • Worry that efficiency will be difficult in corners of the Dalitz plot since D+ starts nearly at rest. • Looks good, changes are smooth. • Model with both MC bin-by-bin and polynomial fit.

  14. D3 Dalitz • Backgrounds from sidebands (offset in E to insure that it remains on the Dalitz plot) • Add in Ks, , f0(1370) to represent possible resonance contributions

  15. D3 Dalitz: Many potential contributions

  16. f2  D3 Dalitz  f0

  17. D3 Dalitz

  18. CLEO-c: D3 Dalitz • Still preliminary • Need to consider other models of  S-wave (for example replace  and f0 contributions by generalized  interaction) to compare with FOCUS which used the K-matrix • Broad agreement with E791 ( contribution, first observation for CLEO)

  19. The Quantum Correlation Analysis ee*D0D0 is C -1 K-+ vs K+- interfere and thus sensitive to DCSD and strong phase Time integrated rate depends on both cosDK and mixing parameter y = /2 K-+ vs K-+ forbidden unless there is mixing. K-+ vs semileptonic measures isolated decay rate and tags flavor of decaying D Different sensitivity to mixing vs DCSD D decays to CP eigenstates also interfere and opposite semileptonics to get isolated rate, flavor tags for yet another dependence on y and strong phase CP eigenstate vs CP eigenstate shows maximal correlations CLEO-c: TQCA -

  20. See PRD 73 034024 (2006) [hep-ph/0507238] by Asner and Sun TQCA RM= (x2+y2)/2 r = Amp DCS/Amp CF - And measure branching fractions simultaneously

  21. TQCA: Single Tags in Data K-+ K+- KK Ks0 Ks00 

  22. TQCA: Double Tags in Simulation M(K-+) M(K-+) M(K+-) M(K-+) M(KK) M(KK) M(K-+) M(KK)

  23. TQCA:Semileptonics Opposite K Flavor Tag Opposite CP- Tag Signal Backgrounds Electron Momentum (GeV) Electron Momentum (GeV)

  24. CP tags vs CP tags clearly shows Quantum Correlation TQCA CP+ CP- C P + CP-

  25. TQCA K-+ vs K-+ K-+ vs K+- Data clearly favors QC interpretation showing constructive and destructive interference and no effect as predicted CP+ vs CP+ CP- vs CP- CP+ vs CP- K vs CP+ K vs CP-

  26. CLEO-c: TQCA • Obviously still preliminary, but very promising • Systematics look tractable (< stats) • Number of CP tags is limit so working on adding more • C+ fraction < 0.06±0.05±? on ’’ • Ultimate sensitivity with projected CLEO-c data set y ±0.012, x2 ±0.0006, cosDK ±0.13, x(sinDK) ±0.024 (needs C+1 initial state from running above the ’’)

  27. Conclusions • Unique information from interference effects in D decays • All since summer 2005 from CLEO • DK*K = 332o±8o±11o and |A(DK*-K+)|/ |A(DK*+K-)|= 0.52±0.05±0.04 in DKK0 Dalitz • D3 Dalitz agrees with E791 on need for low mass  S-Wave contribution • CLEO TQCA sensitive to D mixing parameters and DK

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