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Prospect for studies of CP violation in D V 1 V 2 at BESIII

Prospect for studies of CP violation in D V 1 V 2 at BESIII. Hai-Bo Li Institute of High Energy Physics Beijing, China A.P.C.T.P. Feb.24-27, 2010 YongPyong, Korea. Outline. Brief status of BESIII Motivation on study of D  VV T violation in T odd triple-products in D decays

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Prospect for studies of CP violation in D V 1 V 2 at BESIII

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  1. Prospect for studies of CP violation in DV1V2 at BESIII Hai-Bo Li Institute of High Energy Physics Beijing, China A.P.C.T.P. Feb.24-27, 2010 YongPyong, Korea

  2. Outline • Brief status of BESIII • Motivation on study of D VV • T violation in T odd triple-products in D decays • CP violation in coherent process at BESIII • Summary X.W.Kang and Hai-Bo Li, Phys. Lett.B684, 137(2010) J. Charles, S. Descotes-Genon, X.W.Kang, Hai-Bo Li and G.R.Lu appear in Phys. Rev.D[arXiv:0912.0899 (hep-ph)] Hai-Bo Li (IHEP)

  3. Beam energy: 1.0 - 2.3 GeV Luminosity: 1×1033 cm-2s-1 Optimum energy: 1.89 GeV Energy spread: 5.16 ×10-4 No. of bunches: 93 Bunch length: 1.5 cm Total current: 0.91 A SR mode: 0.25A @ 2.5 GeV IHEP and BEPC-II Collider Linac Storage Ring BESIII 0.1cm 8ns 2.5m 22 mrad 1.5cm Hai-Bo Li (IHEP)

  4. MDC： XY = 130 (m) P/P (0/0) = 0.5 %(1 GeV） dE/dx (0/0) = 6-7 % Solenoid ： 1.0 tesla μcounter： 9 layers TOF： T (ps) = 90 ps Barrel 110 ps endcap EMC：E/√E(0/0) = 2.5 %(1 GeV) 　　　　　　z,(cm) = 0.6cm Hai-Bo Li (IHEP)

  5. BESIII milestones July 18, 2008: First e+e- collision event in BESIII Nov. 2008: ~ 14M (2S) events collected April 14, 2009 ~100M (2S) events collected May 30, 2009 42 pb-1 at continuum collected July 28, 2009 ~230M J/ events collected Jan. 18, 2010-June 1 2010: 1400 pb-1 luminosity on psi(3770) peak for D physics. (200 pb-1 data have been collected last month) Hai-Bo Li (IHEP)

  6. BEPC II Peak Lumi History 3.011032cm-2s-1 Status BEPCII and Data taking 8.4 (1.4 fb1) Hai-Bo Li (IHEP)

  7. Motivation (1) T odd observable in KLe+e:  is the angle between  and e+e plane, and T-odd term 3sincos contains the interference between M1 and bremsstrahlung amplitudes. Large asymmetry observed in KLe+e: A = (13.61.41.5)% [KTeV: arXiv:hep-ex/050801] and agrees well with theoretical prediction: A = (14.31.3)% [L.M.Sehgal and M.Wanninger PRD46, 1035(1992)] with BR(KLe+e) = (3.320.140.28)107 . Hai-Bo Li (IHEP)

  8. Motivation (2) Hai-Bo Li (IHEP)

  9. Motivation (3) D0 decay Poor data in PDG ! D+ decay Hai-Bo Li (IHEP)

  10. Partial waves in D  VV decays Hai-Bo Li (IHEP)

  11. Angular dependence partial waves in DVV Rich final state interaction may induce relatively large CP violation in D  V1V2 (M1M2)(M3M4) ---- provide T-odd observables: The triple-product is connected with angular dependence. Note that non-zero T-odd correlation doesn’t necessarily imply CP violation since the strong phase may fake it. Hai-Bo Li (IHEP)

  12. T violating triple-product Comparing a triple correlation for CP conjugate transitions allows to distinguish CP violation from final state interaction effects, For longitudinal component: For parallel component: Hai-Bo Li (IHEP)

  13. Sensitivity of T violating triple product at BESIII The expected errors on T-odd asymmetry at BESIII with 20 fb1 luminosity on (3770) peak (72106 DDbar pairs). X.W.Kang and Hai-Bo Li, Phys. Lett.B684, 137(2010) Hai-Bo Li (IHEP)

  14. Appear in PRD, 2010 [arXiv:0912.0899 (hep-ph)] Hai-Bo Li (IHEP)

  15. Hai-Bo Li (IHEP)

  16. Quantum correlation Hai-Bo Li (IHEP)

  17. Large branching fraction and reconstruction efficiency Longitudinal CP+ Parallel CP+ Perpendicular CP Hai-Bo Li (IHEP)

  18. CP observables in the correlation Hai-Bo Li (IHEP)

  19. CP observables in combined rates For example, both D VV in the longitudinal polarizations, we construct the angular dependence CP observable: Hai-Bo Li (IHEP)

  20. Sensitivity at BESIII with 20fb1 luminosity Hai-Bo Li (IHEP)

  21. CP violating rate and phase difference From the following combined CP violating decay rate with the parameterization: As an example for , the above formula can be written as: Combining the CP violating rate and polarization fractions, one can extract the phase difference (a-b). Hai-Bo Li (IHEP)

  22. Extracting phase difference From the following formula, if the CP violating rate on the left and polarization fractions on the right side are measured, the strong phase difference can be determined: Hai-Bo Li (IHEP)

  23. Summary • CP violation in D decay is sensitive to New Physics • Rich final state interaction in DVV decays • Interference between different transversity amplitudes can be used to probe CP violation • T-odd triple-product in D VV • Quantum correlation and different polarization amplitudes are combined to probe CP violation • Sensitivities are estimated at BESIII Hai-Bo Li (IHEP)

  24. Thank you! Hai-Bo Li (IHEP)

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