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CP Violation in Charm and Beauty Michael D. Sokoloff University of Cincinnati & Laboratori Nazionali di Frascati de

f CP. f CP. CP Violation in Charm and Beauty Michael D. Sokoloff University of Cincinnati & Laboratori Nazionali di Frascati dell’INFN. The story of CP Violation has changed qualitatively in the past two years.

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CP Violation in Charm and Beauty Michael D. Sokoloff University of Cincinnati & Laboratori Nazionali di Frascati de

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  1. fCP fCP CP Violation in Charm and BeautyMichael D. SokoloffUniversity of Cincinnati & Laboratori Nazionali di Frascati dell’INFN The story of CP Violation has changed qualitatively in the past two years. Babar and BELLE have observed time-dependent CP violation in neutral B-mesons, in accord with the Standard Model. The ensemble of these and other results appear to validate the Kobayashi-Maskawa mechanism as the source of CP violation in the electroweak sector. New Physics may yet be manifest in CP violation measurements to come. Michael D. Sokoloff

  2. fCP Elements of Macroscopic CP Violation Michael D. Sokoloff

  3. b = f1; a = f2; g = f3 Weak Phases in the Standard Model Michael D. Sokoloff

  4. Some Relevant Feynman Diagrams Michael D. Sokoloff

  5. Belle Detector Aerogel Cherenkov cnt. n=1.015~1.030 SC solenoid 1.5T 3.5GeV e+ CsI(Tl) 16X0 TOF counter 8GeV e- Tracking + dE/dx small cell + He/C2H5 m / KL detection 14/15 lyr. RPC+Fe Si vtx. det. 3 lyr. DSSD

  6. BaBar Detector All subsystems crucial for CP analysis SVT:97% efficiency, 15 mm z hit resolution (inner layers, transverse tracks) SVT+DCH: (pT)/pT = 0.13 %  pT+ 0.45 % DIRC: K- separation 4.2  @ 3.0 GeV/c  2.5  @ 4.0 GeV/c EMC:E/E = 2.3 %E-1/4  1.9 %

  7. e+e-  (4S)  BB m- Tag flavor and reconstruct vertex K- Btag m- Brec m+ B0 KS B0 p+ Coherent L=1 state p- Start the Clock Stop the Clock Experimental technique at the (4S) resonance Boost: bg= 0.55 (4S) Exclusive B meson and vertex reconstruction Michael D. Sokoloff

  8. ( ) Identifying Fully Reconstructed B’s For fits, both Belle and Babar characterize signals and backgrounds with PDF’s which utilize Mbc, DE, tagging category, etc. Michael D. Sokoloff

  9. typical mistagging & finite time resolution Tagging errors and finite Dt resolution perfect tagging & time resolution (f-) (f+) B0D(*)-p+/ r+/ a1+ Ntagged=23618 Purity=84% Michael D. Sokoloff

  10. r = estimated tagging dilution 6 hep-ex/020825 v1 Effective tagging efficiency QQ=e(1-2w)2 Michael D. Sokoloff

  11. sin2b golden sample: (cc)KS and (cc)KL 85 x 106 BB evts 2938 events used tomeasure sin2f1 Michael D. Sokoloff

  12. CP odd: sin 2f1 = 0.716  0.083 CP even: sin 2f1 = 0.78  0.17 sin(2b) fit results |lf| = 0.948  0.051 (stat)  0.017 (sys) Scss = sin(2f1 ) = 0.759  0.074 (stat)  0.032 (sys) sin(2f1 ) = 0.719  0.074 (stat)  0.035 (sys)asumming |lf| = 1 (hep-ex/020825, v1) Michael D. Sokoloff

  13. |lf| = 0.948  0.051 (stat)  0.017 (syst) Sf = 0.759  0.074 (stat)  0.032 (syst) } hf =-1 sin(2b) fit results hf =+1 hf =-1 sin2b = 0.755  0.074 sin2b = 0.723  0.158 sin2b = 0.741  0.067 (stat)  0.034 (sys) with |lf| = 1 (preliminary) Michael D. Sokoloff

  14. Golden modes with a lepton tag The best of the best! Ntagged = 220 Purity = 98% Mistag fraction 3.3% sDt 20% better than other tag categories background Consistent results across mode, data sample, tagging category sin2b = 0.79  0.11 Michael D. Sokoloff

  15. r = r (1-l2/2) h = h (1-l2/2) sin2b = 0.741  0.067 (stat)  0.034 (sys) sin2f1= 0.719  0.074 (stat)  0.035 (sys) Standard Model comparison One solution for b is in excellent agreement with measurements of unitarity triangle apex Method as in Höcker et al, Eur. Phys.J.C21:225-259,2001 Nir@ICHEP2002: Im(lyK) = 0.734  0.054 Michael D. Sokoloff

  16. D ~ 2.7 sstimulate theoretical interest; (b ccd) mode B0D*+D*- -sin2b Small ( < 0.1 T) penguin expected • Using angular analysis (126  12) events, measure CP odd fraction: R=0.07  0.06 (stat)  0.03 (syst) B0D*+D*- Im(l+) =+0.31  0.43  0.1 -sin2b = -0.741  0.067 |l+| = 0.98  0.25  0.09 102 tagged events NB: with low statistics, errors are not Gaussian Michael D. Sokoloff

  17. Tree: ~VcbVcd* ~ O(l3) same weak phase as bccs Penguin:~VcbVcd* + VubVud* ~ O(l3) adds additional weak phase (bccd) mode B0J/yp0 Nfit= 40±7 hf = + 1 ~49 eventsA = -0.25  0.35  0.06-S = 0.93  0.49 0.08 Michael D. Sokoloff

  18. N(h’KS)≈147.9±17.3 N(fKS) ≈35.4±7.3 N(K+K-KS) ≈94.3±13.8 sin2b from the penguin decay bsss B fKS B h’KS B fKS B K+K-KS 97% hf= +1 Michael D. Sokoloff

  19. ICHEP2002 CP asymmetry fits for bsss Low statistics. So: Fix |lfK| = 1 If no new physics, SfK = sin2b +0.52 - 0.50 SfK = -0.19 (stat)  0.09 (sys) Preliminary Hiller, hep-ph/020735: “First hint of non-standard CP …” sin(2b(fKS))ave= -0.390.41; ≠ +0.734±0.054 naively, 2.7 s ;  possible new physics & constraints on NP. NB: with low statistics, errors are not Gaussian Michael D. Sokoloff

  20. With Penguins (P): Bpp to measure sin2aeff No Penguins (Tree only): mixing decay Michael D. Sokoloff

  21. BppCP Asymmetry Results PRL 89, 071801 (2002)∫L dt = 78 fb-1 Michael D. Sokoloff

  22. BppCP Asymmetry Results Fit projection in sample of pp-selected events Kp ∫L dt = 88 fb-1 Submitted to Phys Rev (hep-ex/0207055) Preliminary Michael D. Sokoloff

  23. Some Direct CP results Michael D. Sokoloff

  24. CP Violation in Charm Standard model predictions for direct CP violation are zero for Cabibbo-favored and doubly Cabibbo-suppressed decays, and O(10-3) [at most] for singly Cabibbo-suppressed decays. Mixing is predicted to be small. At current levels of sensitivity, look for new physics in doubly Cabibbo-suppressed decays and in mixing. Michael D. Sokoloff

  25. CP Violation in Charm and BeautyA Summary Babar and BELLE have observed time-dependent CP violation in neutral B-mesons, in accord with the Standard Model. Nir@ICHEP2002: Im(lyK) = 0.734  0.054 The ensemble of these and other results appear to validate the Kobayashi-Maskawa mechanism as the source of CP violation in the electroweak sector. New Physics may yet be manifest in CP violation measurements to come. Lots of experimental work is being done. Several “> 2.5s””” effects are stimulating theoretical work. Michael D. Sokoloff

  26. Special Thanks • Yannis Karyotakis • David Lange • Pat Burchat • Andrei Gritsan • Masa Yamauchi • Kay Kinoshita • The Conference Organizersand Staff Michael D. Sokoloff

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