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Flavour Physics and CP violation

Flavour Physics and CP violation. Paris, June 3 rd 2003. D 0 mixing and Charm lifetimes An experimental review. Gianluigi Boca Pavia University and INFN Italy. Outline. Experimental review of the D 0 mixing measurements - formalism in short - review of lifetime ratios

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Flavour Physics and CP violation

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  1. Flavour Physics and CP violation Paris, June 3rd 2003 D0 mixing and Charm lifetimes An experimental review Gianluigi Boca Pavia University and INFN Italy Gianluigi Boca, Flavour Physics and CP Violation 2003

  2. Outline Experimental review of the D0 mixing measurements - formalism in short - review of lifetime ratios - review of D0 DCS hadronic decays measurements - review of D0 Wrong Sign semileptonics decays Experimental review of charm particle lifetime measurements - mesons : D+ , D0 , Ds - baryons : Xc+ , Lc+ , Xc0 , Wc0 Gianluigi Boca, Flavour Physics and CP Violation 2003

  3. Experiments mainly considered in this review experiment beam approx. Luminosity Average st type type total charm E791 fixed target 500 GeV p 105 40 fs Focus fixed target up to 300 Gev g 106 30 fs Selex fixed target 600 GeV S, p, p 104 20 fs Cleo collider e+e-at U(4S) 106 9 fb-1 140 fs Babar collider asym.e+e- at U(4S) >106 91 fb-1 160 fs Belle collider asym. e+e- at U(4S) >106 46.2 fb-1 160 fs Fixed target : Greater Lorentz boost, longer decay lengths Use cut on detachment significance Use reduced proper time : t’  ( L – Ns)/gbc and so smaller acceptance/resolution corrections • Event cleanliness • e+e- collider • g on fixed target • Hadrons on fixed target Collider : greater cleanliness of events

  4. Experimental review of the D° mixing measurements Gianluigi Boca, Flavour Physics and CP Violation 2003

  5. Decay rate to a final state | f  from an initially pure |D0state ( | f   CP | f  and |D0  CP |D0) : G(D0phys→ f )(t) = |  f | Hi | D0 |2 e-gt {¼ (1+|l|2)(eDgt/2 + e-Dgt/2 ) + (1-|l|2) cos(Dmt) + + ½ Re l eDgt/2+ e-Dgt/2+2isinDmt } D0 decay formalism in short D0 weak effective hamiltonian eigenstates : |D1 = p |D0+ q |D0with eigenvaluem1 - ½ g1 |D2 = p |D0- q |D0 with eigenvaluem2- ½ g2 ( Convention :Re (q/p) > 0) Decay rate to a final state | f  from an initially pure |D0state : G(D0phys→ f )(t) = |  f | Hi | D0 |2 e-gt {¼ (1+|l|2)(eDgt/2 + e-Dgt/2 ) + (1-|l|2) cos(Dmt) + + ½ Re l eDgt/2+ e-Dgt/2+2isinDmt } with the definitions Gianluigi Boca, Flavour Physics and CP Violation 2003

  6. x Dm / g  f | Hi | D0 p q y Dg/ 2g  (g1 - g2)/(g1 + g2)  f | Hi | D0 q p      f | Hi | D0  f | Hi | D0 D0 decay formalism in short cont.d where g  ½ ( g1 + g2 ) Dg  g1 - g2 Dm  m1 - m2 Gianluigi Boca, Flavour Physics and CP Violation 2003

  7. t (D0→ K+p-) -1  ycp t (D0→ K-p+) t (D0→ K+K-) -1  ycp t (D0→ K+K-) t (D0→ K-p+) -1  ycp t (D0→ p+p-) ycp = ycp = y= g(CPeven) – g(CPodd) g(CPeven) + g(CPodd) Which are today the experimental possibilities to measure x and y ? 1) D0 lifetime ratios CF/CS to measure y If we assume CP conservation in D0 decays then Same measurement is possible in pp channel Gianluigi Boca, Flavour Physics and CP Violation 2003

  8. 1 d WS(t) dt total RS total WS total RS 2) studies of Wrong Sign D0 hadronic decays Existing examples : • D0 → K+p- and c.c. • D0 → K+p+p-p- and c.c. • D0 → K*+(Ksp+) p- and c.c. • D0 → K+p-p0 and c.c All D0 must be tagged with D* Experimentally one measures or Gianluigi Boca, Flavour Physics and CP Violation 2003

  9. = g e-gtRD + (RD)y’gt + ½RMg2t2 = RD + (RD)y’ + RM } K+p- | Hi | D02 x’ = x cosd + y sind y’ = y cosd – x sind 1 d WS(t) RD K-p+ | Hi | D02 = Rotation by the strong phase d K+p-| Hi | D0 ( ) dt total RS K+p- | Hi | D0 K-p+| Hi | D0 K-p+ | Hi | D0 d  arg K+p-| Hi | D0 K-p+| Hi | D0 WS(t) total RS If CP is conserved in these decays then (taking as an example D0→ K+p-) : with the definitions (PDG 2002 = Cleo conventions): ( ) = arg RM ½(x2 + y2) = ½ (x’2 + y’2) Gianluigi Boca, Flavour Physics and CP Violation 2003

  10. If we allow CP violation, RD , x’, y’, RM of D0 → K+p- may differ from those of D0 → K-p+ . There are various parametrizations for CP in literature; I adopt here PDG 2002 (8 parameterstotal ) : • g e-gtRD(1+AD)2+ (RD)(1+AM)(1+AD)y’-gt + ½(1+AM)2RMg2t2 = g e-gt{RD/(1+AD)2+ (RD)/(1+AM)(1+AD)y’+gt + ½RMg2t2 /(1+AM)2} for D0 → K-p+ K+p- | Hi | D0 RD AM  | q/p | - 1 K+p-| Hi | D0 1 1 d WS(t) d WS(t) K-p+ | Hi | D0 ) ( dt dt total RS total RS K+p- | Hi | D0 K-p+| Hi | D0 K-p+ | Hi | D0 ( ) f  ½ arg  K+p- | Hi | D0 K-p+ | Hi | D0 K+p-| Hi | D0 K-p+| Hi | D0 AD - 1 K+p-| Hi | D0 K-p+| Hi | D0 for D0 → K+p- where RM , x, y, x’, y’ are defined as previously; AD, AM, fandRD are real : and y’+  y’ cosf + x’ sinf = x cos(d-f) – xsin(d-f) ADor AMorf 0 is signal of CP violation y’-  y’ cosf- x’ sinf = x cos(d+f) – xsin(d+f)

  11. = RM (1+AM)2 = RM / (1+AM)2 = RM = ge-gt½ RM g2t2 = ge-gt½(1+AM)2 RMg2t2 1 1 1 d WS(t) d WS(t) d WS(t) dt dt dt total RS total RS total RS total WS total WS total WS total RS total RS total RS 3) studies of WS D0 semileptonic decays in order to measure RM : • D0 → K+m-n and c.c. • D0 → K+e-n and c.c. D0 must be tagged with D* If CP is conserved then for D0 → K+l-n If we allow CP violation then and for D0 → K-l+n = ge-gt½ RMg2t2 /(1+AM)2 Gianluigi Boca, Flavour Physics and CP Violation 2003

  12. review of the D0 lifetime ratios H.Nelson, hep-ex/9908021 (1999) Predictions on x and y  10-2 Gianluigi Boca, Flavour Physics and CP Violation 2003

  13. publication : PRL88 (2002) D0 → K-p- 214260  562 evts D0 → K+K- 18306  18 evts from 23.4 fb-1 data set t (D0→ K-p+) -1  ycp = (0.5  1.0 +0.7-0.8 ) % t (D0→ K+K-) review of the D0 lifetime ratios Gianluigi Boca, Flavour Physics and CP Violation 2003

  14. Belle is still running and certainly will improve this result Gianluigi Boca, Flavour Physics and CP Violation 2003

  15. review of the D0 lifetime ratios cont.d Moriond Conference 2003 BaBar Babar parametrizes lifetimes ratios allowing for possible CP violations t+ for D0 → K+K- or D0 → K+K- t0 from D0 → K-p+ t- for D0 → K+K- or D0 → K+K- <> = (+ +  -) / 2 • A = (+ - -) / ( + + -) • Y  0/<> - 1 Y A 0/ <> If CP is conserved Y coincides with ycp and y Gianluigi Boca, Flavour Physics and CP Violation 2003

  16. Moriond Conference 2003 D0 Lifetime Samples BaBar • All BaBar data from 2000-2002 runs - 91 fb-1 were used. • Four independent samples were isolated, three of which were tagged as D0 or D0 Gianluigi Boca, Flavour Physics and CP Violation 2003

  17. A B A B C D C MeV/c2 GeV/c2 Moriond Conference 2003 D0 Lifetime Samples BaBar Unbinned likelihood fit to (m, t, t) ! (<> , 0, A) m(D0) Fits m = mD+- mD Gianluigi Boca, Flavour Physics and CP Violation 2003

  18. Moriond Conference 2003 Fit Results BaBar • The fit uses all the data Events within 15 MeV/c2 of D0 mass shown here. • Background estimated from mass and lifetime fits. • Statistical uncertainty small, e.g. for K-+ it is »0.9 fsec (»0.5% in y). background Gianluigi Boca, Flavour Physics and CP Violation 2003

  19. Moriond Conference 2003 Summary of Lifetime Ratio Results BaBar No CP violation BaBar is still running and certainly will improve this result Gianluigi Boca, Flavour Physics and CP Violation 2003

  20. D0 → K-p- 20272  178 evts D0 → K+K- 2463  65 evts D0 → p+p- 930  37 evts from 9.0 fb-1 data set data tagged with D* review of the D0 lifetime ratios cont.d Publication : PRD 65 (2002) CLEO II.V ycp = (-1.2  2.5 1.4) % Gianluigi Boca, Flavour Physics and CP Violation 2003

  21. review of the D0 lifetime ratios cont.d Focus Publication : PLB 485 (2000) Data tagged or untagged with D* D0 → K-p- 119738 evts D0 → K+K- 10331 evts ycp = (3.42  1.39 0.74) % Gianluigi Boca, Flavour Physics and CP Violation 2003

  22. review of the D0 lifetime ratios cont.d Publication PRL 83 (1998) E791 D0 → K-p- 35000 evts D0 → K+K- 3200 evts tKK = 0.410  0.011  0.006 tKp= 0.413  0.003  0.004 ycp = (0.73  3.30) % Gianluigi Boca, Flavour Physics and CP Violation 2003

  23. summary of D0 lifetime ratios Also from BaBar first estimate of CP violation parameter in lifetime ratio measurements : -2.0% < Dy < 0.4% 95% CL Measurements already at the 1 % level Certainly BaBar and Belle will improve the precision when more data analysed Gianluigi Boca, Flavour Physics and CP Violation 2003

  24. review of the D0 WS hadronic decays (D*→p+) D0→ K+p- Publication: BaBar preprint, submitted to PRL 83 (2003) BaBar 57.1 fb-1 120000 RS evts 430 WS evts WS M(Kp) (GeV/c2) WS dm (GeV/c2) Open histogram : signal from fit Shaded : backgrounds

  25. = g e-gtRD  + (RD )y’ gt + ½RM g2t2 1 1 d WS(t) d WS(t) dt dt total RS total RS (D*→p+) D0→ K+p- BaBar Performed fit to • Four types of fit : • Fit allowing CP violation terms ( D0 and D0 samples separately) • Fit assuming CP conservation (D0 and D0 samples together) • Fit assuming no mixing allowing CP violating terms • Fit assuming CP conservation and no mixing In their fit they defined the CP violating terms differently from PDG 2002 where + is for D0 and – for D0 BaBar definition of CP violating parameters :

  26. (D*→p+) D0→ K+p- BaBar x’ fit value is negative x’ value fixed at 0 All results consistent with no CP violation

  27. (D*→p+) D0→ K+p- BaBar Gianluigi Boca, Flavour Physics and CP Violation 2003

  28. review of the D0 WS hadronic decays cont.d (D*→p+) D0→ K+p- Preliminary result: ICHEP02 46.2 fb-1 120795  371 RS evts 45031 WS evts Wrong sign Analysis of time-integrated WS/RS ratio RWS = (0.372  0.025 +0.009-0.014 ) % Gianluigi Boca, Flavour Physics and CP Violation 2003 Right sign

  29. review of the D0 WS hadronic decays cont.d (D*→p+) D0→ K+p- Focus Publication : PRL 86 (2001) 36760  195 RS evts 14931 WS evts Analysis of time-integrated WS/RS ratio RWS = (0.404  0.0850.025) % Focus is presently working on the time dependent analysis Gianluigi Boca, Flavour Physics and CP Violation 2003

  30. Performed fit of: 1 d WS(t) dt total RS review of the D0 WS hadronic decays cont.d (D*→p+) D0→ K+p- 9 fb-1 dataset 13527  116 RS evts 44.8+9.7-8.7 WS evts CLEO II.V Publication : PRL 84 (2000) • three types of fit : • Fit allowing CP violation terms • Fit assuming CP conservation • Fit assuming no mixing allowing CP violating terms Gianluigi Boca, Flavour Physics and CP Violation 2003

  31. (D*→p+) D0→ K+p- CLEO II.V All results consistent with no CP violation and no mixing Gianluigi Boca, Flavour Physics and CP Violation 2003

  32. summary of WS : D0→ K+p- Summary of RDCS in D0 → K+p- assuming no CP violation, no mixing Gianluigi Boca, Flavour Physics and CP Violation 2003

  33. summary of WS : D0→ K+p- Summary of mixing result of E791, CLEO (2000) and preliminary BaBar (2003) BaBar preliminary % Focus semileptonics expected sensitivity %

  34. review of the D0 WS hadronic decays cont.d (D*→p+) D0→ K+p+p-p- 9 fb-1 dataset 13735 RS evts 44.8  14 WS evts CLEO II.V Publication : PRD 64 (2001) Analysis of time-integrated WS/RS ratio (phase space averages MC uncertainties) RWS = (0.41+0.12-0.11 0.04) % * (1.07 0.10) Gianluigi Boca, Flavour Physics and CP Violation 2003

  35. review of the D0 WS hadronic decays cont.d (D*→p+) D0→ Ksp+p- Dalitz analysis 9 fb-1 dataset Dalitz analysis 5299 evts CLEO II.V Publication : PRL 89 (2002) Gianluigi Boca, Flavour Physics and CP Violation 2003

  36. (D*→p+) D0→ Ksp+p- CLEO II.V Rich resonant substructure shows WSD0→ K*+(890)p- + c.c. contributions. First measure of strong phase d between CF D0→ K*-(890) p+ and DCS D0→ K*+(890)p- . Assuming CP conservation then : ( ) ( ) K*+p- | Hi | D0 K*-p- | Hi | D0 d  arg = 1800 - arg K*+p-| Hi | D0 K*+p-| Hi | D0 Gianluigi Boca, Flavour Physics and CP Violation 2003

  37. B(D0 →K*+p-) = (0.50.2+0.5-0.1+0.4-0.1)% B(D0→K*+p- ) (D*→p+) D0→ Ksp+p- CLEO II.V From table (neglecting error correlations) : d = 1800 – ( 321103+15-3 - 150  22+2-5) = 90  150 Strong phase consistent with zero Also measured Also performed analysis separately D0 and D0 samples. NO statistically significant CP violation effect. Gianluigi Boca, Flavour Physics and CP Violation 2003

  38. review of the D0 WS hadronic decays cont.d (D*→p+) D0→ Ksp+p- Also Babar recently (Moriond Conference 2003) showed the Dalitz plot of this channel BaBar K*(890) ! K0+ K*(890) ! K0- ? Gianluigi Boca, Flavour Physics and CP Violation 2003

  39. review of the D0 WS hadronic decays cont.d (D*→p+) D0→ K+p+p0 9 fb-1 dataset 389 WS evts CLEO II.V Publication : PRL 87 (2001) RWS = (0.43+0.11-0.100.07)% Gianluigi Boca, Flavour Physics and CP Violation 2003

  40. publication : Int. J. Mod., Phys A:17 n.22 (2002) B(D0→ Klp0) = (0.88  0.9  0.9) % B(D0→ Ksp0) A  G(D0 → Ksp0) - G(D0→ Klp0) = (0.06  0.05  0.05) % G(D0 → Ksp0) + G(D0→ Ksp0) a useful measurement from Belle from 23.4 fb-1 data set D* tagged sample A is consistent with 0 If precision will improve in this measure in the future, it will be possible impose constraints on dKp strong phase * * Golowich and Pakvasa, PLB 505 (2001) Gianluigi Boca, Flavour Physics and CP Violation 2003

  41. review of the D0 WS semileptonic decays measure of RM without complications of DCS decays Publication : PRL 77 (1988) Believe it or not, thist is still the only result in literature! E791 (D*→p+)D0 → K+m-n1.8 +12.1–11.0 WS evts 1267  44 RS evts (D*→p+)D0 → K+e-n 4.4 +11.8–10.5 WS evts 1237  45 RS evts

  42. (D*→p+) D0→ K+l-n } RM = (0.16+0.42-0.37)% for D0 → K+e-n RM = (0.11+0.30-0.27)% RM = (0.06+0.44-0.40)% for D0 → K+m-n review of the D0 WS semileptonic decays cont.d E791 Simultaneous fit to the Q plot and the proper time that has a  gt2 e-gt dependence. CP violation NOT allowed in this fit RM < 0.50% at 90 % CL Gianluigi Boca, Flavour Physics and CP Violation 2003

  43. review of the D0 WS semileptonic decays cont.d Future Focus has a large sample of D0 semileptonic decays and they are working to extract RM They expect a sensitivity of  0.1 % at 95% CL BaBar and Belle ? Gianluigi Boca, Flavour Physics and CP Violation 2003

  44. Experimental review of the charm particle lifetime measurements here I will show only plots of results after 2000 Gianluigi Boca, Flavour Physics and CP Violation 2003

  45. u c s d W-annihilation Theory mini-summary D+ D0 Ds destructive interference term B A R Y O N S In the context of OPE and 1/mc expansion different diagrams can contribute to the total decay width constructive interference term spectator term

  46. Charm meson lifetimes D+ Focus Publication : PLB 537 (2002) D+→K-p+p+ t = 1039.4  4.3  7.0 fs Background subtracted acceptance corrected Definition of reduced proper time : t’  ( L – Ns)/gbc L primary-secondary detachment s  event by event error on L N  detachment cut ( L/s > N ) Gianluigi Boca, Flavour Physics and CP Violation 2003

  47. Charm meson lifetimes cont.d D+summary My average : 1042.7  7.0 Gianluigi Boca, Flavour Physics and CP Violation 2003

  48. Charm meson lifetimes cont.d D0 Focus D0→K-p+ Publication : PLB 537 (2002) D0→K-p+p-p+ t = 409.6  1.1  1.5 fs Background subtracted acceptance corrected K-p+ K-p+p+p-

  49. Charm meson lifetimes cont.d Selex D0 } D0→K-p+ Publication : PRL 86 (2001) 10210 evts D0→K-p+p-p+ t = 407.9  6.0  4.3 fs Total sample Total sample Background subtracted acceptance corrected

  50. Charm meson lifetimes cont.d D0 summary Gianluigi Boca, Flavour Physics and CP Violation 2003

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