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Julie Malcl ès LPNHE Paris – Universit é Paris 6 For the BaBar Collaboration

 and  measurements from BaBar. Julie Malcl ès LPNHE Paris – Universit é Paris 6 For the BaBar Collaboration. PANIC 2005 Santa Fe, New Mexico, USA October 24 th -28 th 2005. Introduction.  and : challenging measurements.  from , () 0 : “penguin pollution”.

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Julie Malcl ès LPNHE Paris – Universit é Paris 6 For the BaBar Collaboration

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  1.  and  measurements from BaBar Julie Malclès LPNHE Paris – Université Paris 6 For the BaBar Collaboration PANIC 2005 Santa Fe, New Mexico, USA October 24th-28th 2005

  2. Introduction  and : challenging measurements  from , ()0: “penguin pollution”  from B+D(*)0K(*)+: small interferences CKM standard fit without  and  measurements:  precisely measured with golden modes J/ KS, D*D*,… sin(2+) from B0D/

  3. Measuring with B: SU(2) symmetry Time dependent asymmetries in h+h-: “Penguin pollution”: Tree: Penguin: Neglecting P, S measures : In reality it measures eff  additional info. needed for  Gronau-London, PRL, 65, 3381 (1990) Lipkin et al., PRD 44, 1454 (1991) Isospin analysis: Neglecting EWP, h+ h0 (I=2)=pure tree Triangle relations allow determination of penguin induced shift in : | - eff|

  4. Results for B +- HEP-EX 0508046 (2005) PRL, 95, 151803 (2005) C = -0.09  0.15  0.04 S = -0.30  0.17  0.03 sPlot • All measurements with 227106 B pairs • No observation of CP violation • 00 observation (indicates non-negligible contribution of penguin) and measurement of C00 • New meas. BR(+-) with efficiency corrected for the effects of final-state radiation Signal enriched sample Signal enriched sample 00 +0 PRL, 94, 181802 (2005) sPlot: +0, K+0

  5. Results for B Signal enriched sample +- Data: 232 106 B pairs  PRL 95, 041805, (2005) V-V state: need angular analysis: more difficult transverse longitudinal • fL~1 ~100% longitudinally polarized~pure CP even state • interference with a1, ,  neglected (small syst.) • B bkg = main source of syst. Signal enriched sample 00 Data: 227106 B pairs • No significant signal seen • fL=1 assumed for most conservative upper limit • small BR small penguin contribution in  modes •  good sensitivity to  expected PRL, 94, 131801 (2005)

  6. Signal MC +– 00 2.9  –+ Measuring with B()0+-0 : Dalitz analysis Isospin analysis: Not a CP eigenstates  pentagonal relations EWP neglected: 12 unknowns for 13 observables  in principle possible Unfruitful with the present statistics: current data does not constraint  A. Snyder and H. Quinn, PRD, 48, 2139 (1993) Time dependent Dalitz analysis assuming Isospin symmetry: fk relativistic Breit-Wigner form factors Interference between the  resonances at equal masses-squared gives information onstrong phases between resonances can be constrained without ambiguity Direct CP asymmetries:

  7. Constraints on  •  • 8 solutions within [0,] • Need more statistics •  • Golden mode for  (smaller penguin • contribution in  modes wrt ) • Additional assumption: neglect possible • I=1 amplitudes (quasi2body assumption) • : • constrained with no ambiguity at 1 • Combined constraint: • in very good agreement with CKM fit value  = (113 +27−17 ± 6)º , , CKMfitter = (103+10-9)º

  8. Idea: using interference between B-D0K- and B-D0K- decays where the D0 and the D0 decay to a common final state f Ksp+p- K+p- Ksp0 K+K- p+p- Ksf Ksw • from direct CP violation: B-D()K()-  b c color allowed b u color suppressed Relative strong phase B unknown Rel. weak phase  Gronau-London-Wyler: Phys. Lett. B265,172, B253 483 (1991) CP eigenstates Atwood-Dunietz-Soni: Phys. Rev. Lett. 78, 3257 (1997) DCSD D0and CA D0 ex. : B-→ (K+p-)D K- Critical parameter: rB Larger rB, larger interference, better sensitivity to  Giri-Grossman-Soffer-Zupan: Phys. Rev. D68 054018 (2003) D0→ Ksp+ p-Phys. Rev. Lett. 78, 3257 (1997)

  9. Results for GLW (f=CP eigenstates) • 3 independent observables: • A CP+R CP+=-ACP-RCP- • 3 unknowns:, , rB() 214106 B pairs hep-ex/0408082 123106 B pairs PRD 71, 031102 (2005) 214106 B pairs PRD 72, 71103 (2005) • Theoretically very clean • No strong constraints yet on  because rB() small • Need more statistics

  10. 0<dD<2p rD±1s 51°<g<66° g[0,p] Results for ADS (f=K+-) • Small branching fractions • Amplitudes ~ comparable • 2 observables for 3 unknowns Interference • Input: • rD=0.060.002 232106 B pairs hep-ex/0504047 PRD 72, 71104 (2005) No signal seen D(*)K: rB<0.23 and rB2 <0.162 @ 90%CL

  11. PRL 95, 121802 (2005) hep-ex/0507101 Results for GGSZ: (f=KS+-) • Final state accessible through many different decays  need Dalitz analysis • Weak phase , strong phase  and magnitude of suppressed-to-favored amplitudes • rB()extracted from a fit to the interference pattern between D0 and D0 in the Dalitz plot • 12 x ,y measured for three • modes: DK- , DK-,DK- • can be converted into • constraints on , B(), rB()  = (67 ± 28 ± 13 ± 11)° CP fit gives: 1 and 2 level contours in the planes ( , suppressed-to- favored ratio) from the three modes DK- , DK- , DK- taking all 3 modes results simultaneously (GLW+ADS: rs=0.28+0.06-0.10)

  12. Constraints on  • GGSZ method: powerful tool: the golden mode for  • GLW and ADS methods: • limits on suppressed-to-favored ratios rB(*) • more statistics needed to really constraint  • combining different measurements helps: combination of GLW/ADS (WA) and GGSZ(BaBar) with all measured modes: GGSZ = (67 ± 28 ± 13 ± 11)° = (67 ± 33)° GLW,ADS,GGSZ CKMfitter = (51+23-18)º

  13. Conclusions • Best  measurement:  (Lucky2: longitudinal polarization dominates and small penguin pollution) • Best  measurement: Dalitz analysis GGSZ , , WA= (98.6+12.6-8.1)º GLW,ADS,GGSZ WA = (63+15-12)º • All results in good agreement with the global CKM fit • Measure  at B-factories considered ~ impossible few years ago! • SM fit: ,  and  determine (,) nearly as precisely as all data combined • New era: constraints from angles surpass the rest with increasing statistics

  14. Backup slides: • CKM matrix and unitarity triangle • PEP-II performances • The BaBar detector • Analysis techniques: • T measurement • B kinematical variables: mES and E • Event shape variables • Cherenkov angle • General common features • Further details on ,  isospin analysis • +- the golden mode for measuring  • Method for B()0 Dalitz analysis • Extrapolations for B isospin analysis • 0 efficiency measurement • sPlots technique • Combined results for GLW and ADS in B-→D0K*- • GGSZ fit results

  15. CKM matrix and unitarity triangle Quark sector:masses eigenstates  gauge eigenstates Mixing between flavour and weak eigenstates described by 3 3 matrix with 3 real parameters and one single phase CP violation possible in the SM only if CKM matrix is complex i.e. UT area non zero i.e. 0  

  16. e+ e- The BaBar detector Silicon Vertex Tracker (SVT) 1.5T magnet Drift Chamber (DCH) Detector of Internally Reflected Cherenkov Light (DIRC) Electromagnetic Calorimeter (EMC) Instrumented Flux Return (IFR) Pairs of B mesons from (4S) decays: (4S)B0B0, B+B- Boost of (4S) in the lab frame: bg  0.56

  17. PEP-II performances

  18. coherent BB production Analysis techniques: time dependent measurements B-Flavour tagging Exclusive B meson reconstruction bg ~ 0.55 Dt=1.6 ps Dz 200, 250 mm • Time dependent measurements, flavor tagging: • BB are in a coherent state at production • There is a coherent evolution until Btag decays • Breco’s flavour determined from Btag’s flavour and t • Boost: t measured via space length measurement between Btag and Breco z • Flavor of the Btag is determined by its decay product: charge of leptons, kaons, pions

  19. BB events qq events (q=u,d,s,c) Analysis techniques: kinematics and event shape Beam Energy-substituted mass Energy difference Event shape (4S) rest frame s(DE) : mode dependent s(mES)  3 MeV Event shape variables examples:

  20. Analysis techniques: K/ discrimination Cherenkov angle versus momentum: K/ separation versus momentum: K/ >2.5 up to 4 GeV/c

  21. Analysis techniques: common features for , ,  • The 3 analyses (B  ππ, B  , B  π (Dalitz πππ)) sharethe same philosophy and use the same techniques: • Unbinned maximum likelihoodfit using mES, E, NN/F, t, c for ππ/Kπ, Dalitz variables for π, resonance mass and helicity for . • Each component hasits own modelingin the likelihood: • Correctly and misreconstructed signal events. • Continuum, charmed and charmless B backgrounds (up to 20 modes for ). • Simultaneous fitof Signal/background yields, free parameters describing the backgrounds, CP parameters and (polarization). • Determination of t resolution function and mistag rates withfully reconstructed events. • Better statistical sensitivity than traditional “cut and count” approaches. • Better control of the systematics thanks to this global likelihood technique.

  22. Further details on,  isospin analysis • Assumptions: • neglect EW penguins • (shifts  by ~ +2o) penguins • neglect SU(2) breaking • in ρρ: Q2B approx. • (neglect interference)  can be resolved up to an 8-fold ambiguity within [0,] Unknowns Observables Constraints Account , T+–, P+–, T+0, P+0, T00, P00 B+–, S , C B+0, ACP B00, (S00),C00 2 isospin triangles and one common side 13unknowns – 7 observ. – 5 constraints – 1 glob. phase = 0 

  23. +- the golden mode for measuring  Analysis more difficult: • 2 π0 in the final state. • Wide  resonances. • V-V decay: L=0,1,2 partial waves components: • Need angular analysis. But eventually the best mode: • First measurement of α performed by BABAR in :PRL, 93, 231801 (2004). • Branching fraction ~ 6 times larger than for B→ ππ. • Penguin pollution much smaller than in B→ππ • fL ~1.0  are ~100% longitudinally polarized, transverse part suppressed at the tree level: (m/MB)2B0-+ is almost a pure CP-even state! Helicity Frame Longitudinal (CP-even state) Transverse (Mixed CP state)

  24. Method for B()0 Dalitz analysis hep-ex/0408099 • 2 steps analysis: • Fit 16 Breit-Wigner parameters related to the quasi two body parameters S, C,… • Fit results + correlation matrix: 213106 B pairs  simultaneous extraction of weak and strong phases, 

  25. Extrapolations for B isospin analysis Eur. Phys. J. C41, 1-131, CKMfitter group, (2005)

  26. Analysis techniques: 0 efficiency

  27. sPlot technique Reference: François Le Diberder and Muriel Pivk, physics/0402083

  28. g[0,p]&(dD+dB)[0,2p] (semi-log scale) 1-CL 1-CL 1s 1s 2s 2s GLW ADS combination 3s g [75°,105°](excluded @95.4% CL) 3s rsB g(deg) Combined results for GLW and ADS B-→D0K*- Frequentist approach (CKM-Fitter EPJ,C41,1 (2005)) to extract  and rb from ADS/GLW combination for B-→D0K*- modes:  [75º, 105º] @95.4% CL

  29. ~ ~ ~ ~ ~ D0K- D*0[D00]K- D*0[D0]K- 282 ± 20 90 ± 11 44 ± 8 Results for GGSZ: (f=KS+-) NEW 42 ± 8 • x ,y : • ~ gaussian distributions • Small statistical • correlations • Frequentist treatment • to convert them into • constraints on • , B(), rB()

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