1. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20021 New results from B A B AR Marie-Hélène Schune Laboratoire de l’Accélérateur Linéaire Orsay, France All numbers are preliminary Brookhaven National Laboratory Particle Physics Seminar May 20, 2002

2. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20022 New results from B A B AR I will not talk about –sin2  in charmonium modes : 1.B A B AR and PEPII 2.Charmless B decays : –B 0 , K  or KK –B 0  0  0 3.The “B recoil” physics : –semileptonic branching fractions of B + and B 0 –D meson production in B decays sin2  0.75  0.09  0.04 56 fb -1 Winter 2002 conferences

3. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20023 –CKM matrix has 4 real parameters (one phase included) –2 are well known : =|V us |=sin(  Cabbibo )=0.2205  0.0018 A =|V cb |/ 2 =0.83  0.06 –unitarity of the CKM matrix leads to constraints that can be tested: CKM matrix for 3 generations B d    ,    , … B d  J/  K s, D* + D* -,… B  D* , DK, K  B , ,  l,  l,… B d  B d, B d  B  D ( * ) l,D ( * ) ,… Unitarity Triangle  

4. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20024 ) DIRC (PID) 1.5T solenoid CsI(Tl) EMC Instrumented Flux Return Silicon Vertex Tracker Drift Chamber e + (3.1GeV) e - (9GeV) SVT: 97% efficiency, 15  m z resol. (inner layers, perpendicular tracks) Tracking :  p T )/p T = 0.13% P T  0.45% DIRC : K-  separation >3  for P<3.5GeV/c EMC:  E /E = 1.33% E -1/4  2.1% The B A B AR detector

5. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20025

6. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20026 PEP-II asymmetric B Factory 9GeV e - on 3.1GeV e + :  s~10.58 GeV for B 0 : coherent neutral B pair production and decay (p-wave) boost of  (4S) in lab frame :  =0.55

7. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20027 Running at the  (4S) Off On PEP-II B A B AR

8. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20028 May 2 nd : –PEPII delivered : 87 fb -1 –BABAR recorded : 83 fb -1 (including 9 fb -1 off peak ) results for 55 fb -1 B factory performances daily integrated luminosity

9. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 20029 2 - Charmless B decays Study of penguins diagrams Possible direct CP violation   B 0 , K  or KK –Branching fractions (  eff ,  ) –CP violations measurements (  eff,  ) B 0  0  0 (  eff  ) (,)(,)    

10. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200210 B 0  and CP violation (1) BF(B 0  ) << BF(B 0  K  ) penguins contributions may be large Hadronic Penguin Amplitude (P) Tree amplitude (T) Tree only : =  f e 2i   C  =0 S  =sin(2  ) Tree+Peng. C   0 S  =sin(2  eff ) mixing e -2i 

11. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200211 B 0  and CP violation (2) perfect flavour tagging & time resolution realistic mis-tagging & finite time resolution S  =0.7  and C  =0. f + : B 0 tag

12. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200212 Main variables : –|cos  S | : angle between the B 0 sphericity axis and the sphericity axis of the rest of the event – F : Fisher discriminant based on “energy flow cones” (CLEO) B 0 , K  or KK kinematics “Jets” Candidate Axis of “Rest Event” Candidate |cos  S | Candidate

13. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200213 Signal MC  ~2.6 MeV background B 0 , K  or KK : m ES and  E Energy substituted mass : –dominated by the beam energy knowledge  E : assume  mass –dominated by the tracking resolution  (  E)~26 MeV  KK KK ~325 MeV background m ES 45 MeV

14. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200214 B 0 , K  or KK : the PID (1) The DIRC Measure Angle of Cherenkov Cone in quartz –Transmitted by internal reflection –Detected by PMTs Particle Quartz bar Cherenkov light Active Detector Surface

15. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200215 DIRC PMT +light catchers DIRC stand-off box, magnetic shielding and electronic crates

16. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200216 B 0 , K  or KK : the PID (2) DIRC performances measured on data using D*  D 0  and D 0  K   (  c )  2.2 mrad K/  separation 2.5  p range of 2-body B decays at B A B AR

17. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200217 B 0 , K  or KK : analysis strategy Start with a B 0  h + h - (no PID) 5.2 5.24 5.28 m ES ~17600 events for ~56 fb -1 unbinned max L with  E, m ES, F,  1c,  2c measure N  N K  N KK and add  t and tagging information (as for sin2  ), fix the yields extract S  and C 

18. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200218 B 0  B0KB0K B 0 , K  or KK :branching fractions results ModeYield Branching Fraction (10 -6 ) K  Asymmetry (A K   B 0  +  - B0K-+B0K-+ B 0  K + K - Likelihood projections : remove one 1 variable from fit ; cut on L proba m ES  E small cross-feed ~83 B 0  ~356 B 0  K 

19. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200219 B 0 , K  or KK : BF comparison CLEO 9 fb -1 B A B AR 56 fb -1 BELLE 31fb -1 BF( B 0  +  - )(10 -6 ) 4.3  1.6  0.55.4  0.7  0.45.1  1.1  0.4 BF( B 0  K -  + )(10 -6 ) 17.2  2.5  1.217.8  1.1  0.821.8  1.8  1.5 BF( B 0  K - K + )(10 -6 ) <1.9 at 90%CL<1.1 at 90%CL<0.5 at 90%CL AKAK -0.04  0.16-0.06  0.05  0.01-0.06  0.08  0.01 BF(B 0  ) << BF(B 0  K  )

20. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200220 B 0 , K  or KK : CP analyses  t Time information  t : –resolution dominated by B tag vtx (  (  z) ~ 180  m) –extracted from data B reco sample (D (*) ,D (*) ,D (*) a 1 …) –Background shape : side bands Similar to sin(2  ) analyses

21. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200221 NN output Not Used Prob(B 0 ) B Flavour tagging methods For electrons, muons and kaons use the charge correlation b c dd l-l- B0B0 D, D* W- Lepton Tag b d B0B0 W- W+ cs K *0 d Kaon Tag Each category is characterized by the probability of giving the wrong answer (mistag fraction w ) Multivariate analysis exploiting the other kinematic information of the event, e.g.,  Momentum spectrum of the charged particles  Information from non-identified leptons and kaons  Soft  from D* decay Neural Network Hierarchical, mutually exclusive, tagging categories

22. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200222 B 0 , K  or KK : CP analyses tagging Split the events into 4 tagging categories : –leptons –kaons –NT1 –NT2 Performances obtained on data (B reco sample) Similar to sin(2  ) analyses NN type tagging leptons kaons NT1 NT2 m ES

23. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200223 B 0 , K  or KK : CP analyses validation Validation : measure  B on  /K  sample : Validation : measure  m d  B =1.66  0.09 ps  m d =0.517  0.062 ps -1 Select the K  events and plot A mix

24. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200224 B 0 , K  or KK : CP analyses results S  =-0.01  0.37  0.07 S   [-0.66,+0.62] at 90 % CL C  =-0.02  0.29  0.07 C   [-0.54,+0.48] at 90 % CL ~ 27 B 0  ~9 Background ~25 B 0  ~9 Background Select the B 0  events Plot the asymmetry between B 0 tag and B 0 tag events

25. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200225 BBNS: QCD FACTORISATION APPROACH: M. Beneke, G. Buchalla, M. Neubert and C.T. Sachrajda Nucl.Phys.B606 (2001) 245 ( ,  ) constraints from S  and C  CKM Fitter H. Höcker, H. Lacker, S. Laplace and F. Le Diberder Eur. Phys. J. C21 225-259 (2001) http://ckmfitter.in2p3.fr/

26. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200226 B 0 , K  or KK : CP comparisons Belle (K Trabelsi Moriond): -C  (BABAR)  2 (S   C   A 

27. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200227 Search for B 0  0  0 BF(B 0  0  0 ) : –measured  isospin analysis to get  from B 0  +  - (M. Gronau, D. London Phys Rev Lett. 65 3381-3384 (1990)) –upper bound  still a useful constraint: (Y. Grossman, H. Quinn Phys Rev D 58 017504 (1998)) Experimentally challenging : –low BF expected (th. predictions : 10 -7 - few 10 -6 ) –purely neutral final state Recent results : Yieldlimit (10 -6 ) (90% CL) CLEO (9 fb -1 )6.2 +4.8 -3.7 5.7 BELLE (30 fb -1 ) 12  6 5.6

28. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200228 Main variables : –|cos  S | : angle between the B 0 sphericity axis and the sphericity axis of the rest of the event – F : Fisher discriminant based on the “energy flow cones” –m EC : energy constrained mass –  E = E * B –  s/2 in the CMS Search for B 0  0  0 : analysis (1) “Jets” Candidate Axis of “Rest Event” F Candidate

29. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200229 Search for B 0  0  0 : analysis (2) The B     0 background : –event shape similar to the signal one –m EC only slightly wider (small   missing) –  E is the only discriminating variable –in the fit : fix BF( B     0 )=2.410 -5 (from CLEO upper limit)  E (GeV) -.4 -.2 0.2.4 B 0B 0 B000B000

30. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200230 Unbinned maximum L fit using F PDF and (m EC,  E ) PDF Compare with an optimized cut and count analysis : Fit yield : Search for B 0  0  0 : results BF(B 0  0  0 ) < 3.4 10 -6 at 90 % CL Main systematics : neutral efficiency continuum m EC param. F param. B     0 yield 54 fb -1

31. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200231 3 - The “B recoil” physics generic B decay B type known  should allow (in principle !) to measure all B BF Will show : leptonic studies D 0 and D  production

32. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200232 The “B recoil” physics B factories : the world’s largest sample of reconstructed B mesons 56 fb -1 B 0 sample N signal =13743  125 B + sample N signal =12909  120 Reconstruct the Cabibbo-favored hadronic decays :

33. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200233 Inclusive semileptonic B decays Inclusive rate is large –Sides of the unitarity triangle |V cb | and |V ub | –B  X c e is large –B  X u e is an experimental challenge (0,0) (  )    (1,0)

34. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200234 Compare b + /b 0 with  (B + )/  (B 0 ) : Extract the prompt and cascade lepton spectrum from the charge correlation with the B reco : –B -  X c e - –B +  X c e + –B 0 : correct for mixing CLEO results (2.4 fb -1 ) using B 0 tagged sample and  (4S)  l : –b 0 = (10.78  0.60  0.69)% –b + = (10.25  0.57  0.65)% –b + /b 0 = Inclusive semileptonic B decays

35. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200235 Electron identification Variables : –E/p –Shower shapes –DCH and DIRC Performances measured on data: 90% Backgrounds : -  conversions  0 dalitz decays -J/  decays 10 -3 p (GeV)

36. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200236 Background subtracted electrons spectra Rightsign Wrong sign B  N right sign = N + p B 0 N right sign =N 0 p (1-  d )+N 0 c  d N wrong sign =N 0 p  d +N 0 c (1-  d ) results on 21 fb -1

37. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200237 b + /b 0 =.950 .080 .091 b + /b 0 =.99 .10 .03 b 0 and b + results BF results :ratio : B+B+ B0B0

38. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200238 Inclusive branching fractions of B 0 and B + to charmed hadrons –Enters in the n c (= mean charm per B decay ) computation For each B specie two measurements are performed : The absolute BF : BF(B  DX) with D = D 0 or D + –“large statistics” –Need  (D) from MC The wrong D ratio : –Wrong D sample statistically limited –Need to correct for mixing for the B 0 –More MC independant D production in B decays DDDsc,…DDDsc,… b c s DDDsc,…DDDsc,… WRONG RIGHT q c B 0 or B - ( )

39. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200239 D production in B decays reconstruction Hadronic : –B 0  D*  D*  D*a 1 Semileptonic : B 0  D  l fit to cos  B-D*l variable m ES cos  B-D*l D reconstruction : D 0  K  and D   K  50 fb -1

40. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200240 BF(B  DX) Fit N( D ) and correct for B rec background  BF(B  DX) ( ) Brec : B 0  D*l M(K  ) M(K  ) Brec : B 0  D*  D*  D*a 1 BF( B 0  D 0 X)(%) Semilep. 57.1  3.3  4.6 Hadronic 59.3  5.9  3.9 Combined 57.9  2.9  2.1 (*)  3.5 (**) ( ) BF( B 0  D  X)(%) Semilep. 35.7  2.8  3.9 Hadronic 35.3  4.3  3.8 Combined 35.6  2.3  1.1 (*)  3.6 (**) (*) Correlated syst. (**) Uncorrelated syst.

41. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200241 w (D) for neutral B mesons Correlate the D and the B flavours : –For B 0 : should correct for mixing done on an optimized time interval (|  t|<2.5 ps)  reduced statistical uncertainty,  m d dependance  obs = Mix Mix+Unmix =  d + w (1  2  d ) Unmix Mix Brec : B 0  D*l Brec : B 0  D*  D*  D*a 1 M(K  ) w ( B 0  D  X) (%) Semilept. 7.3  3.7  1.9 Hadronic 8.9  7.1  1.8 Combined 7.7  3.3  1.4  0.8 w ( B 0  D 0 X ) (%) Semilept. 15.9  3.5  2.4 Hadronic 9.6  4.7  1.1 Combined 13.1  2.8  1.5  0.6

42. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200242 Results suggest B 0 spectator quark effect negligible in wrong D production Results consistent with world data (“ B admixture”) In the future : –Add the B  sample –100 fb -1 – start to look for D s and  c (looser B reco selection ?) BF( B 0  D 0 X ) = ( 50.3  3.0  3.7 ) % BF( B 0  D 0 X ) = ( 7.6  1.7  1.1 ) % BF( B 0  D + X) = ( 32.8  2.5  3.5 ) % BF( B 0  D - X) = ( 2.7  1.2  0.6 ) % D production in B decays Better understanding of the overall picture of the B decays Compare BF( B 0  D 0 + D + X) = (83.1  6.4) % with world data: BF( B admixt  D 0 + D + X) = (78.5  3.4) % 30 or 51 fb -1

43. New results from B A B AR, Marie-Hélène Schune, BNL, May 20th 200243 Summary A true factory of B mesons : –BF(B 0  +  - ) = (5.4  0.7  0.4) 10 -6 –BF(B 0  K +  - ) = (17.8  1.1  0.8) 10 -6 Unfortunately not enough to get B 0  0  0 –BF(B 0  0  0 ) < 3.4 10 -6 at 90 % CL CP violation results : –S  =-0.01  0.37  0.07 –C  =-0.02  0.29  0.07 “B recoil” physics is starting : –Semi leptonic measurements –D mesons production in B decays BF( B 0  D 0 X ) = ( 50.3  3.0  3.7 ) % BF( B 0  D 0 X ) = ( 7.6  1.7  1.1 ) % BF( B 0  D + X) = ( 32.8  2.5  3.5 ) % BF( B 0  D - X) = ( 2.7  1.2  0.6 ) %