1. Heavy Flavour Physics News from the Tevatron Wendy Taylor for the CDF and D Ø Collaborations APS/AAPT 2010, Washington, DC, February 13-16, 2010

2. Where is the antimatter in the Universe?Where is the antimatter in the Universe? Why are there 3 generations of matter? (only 3?)Why are there 3 generations of matter? (only 3?) How does the strong force bind quarks into hadrons?How does the strong force bind quarks into hadrons? How does the electroweak force cause hadrons to decay?How does the electroweak force cause hadrons to decay? W. Taylor, APS/AAPT 2010 2 The b Quark as a Physics Probe Primary vertex B decay vertex Displaced track

3. Why study B physics at the Tevatron?Why study B physics at the Tevatron? –Large rate: –Tevatron energy sufficient to create states not accessible at the e + e - B factories However, backgrounds are large:However, backgrounds are large: The Tevatron is a B Factory W. Taylor, APS/AAPT 2010 3

4. Run II Tevatron Proton-Antiproton Collider  s=1.96 TeV  s=1.96 TeV L = 2.5  10 32 cm -2 s -1 L = 2.5  10 32 cm -2 s -1  Ldt = 50 pb -1 per week  Ldt = 50 pb -1 per week Main Injector Tevatron DØCDF Chicago   p source Booster Fermi National Accelerator Laboratory W. Taylor, APS/AAPT 2010 4

5. Detectors  Excellent muon and tracking coverage  high yields u Extended muon system |  |<2.0 u Tracking up to |  |<3.0 Solenoid and muon toroid polarities flipped every two weeksSolenoid and muon toroid polarities flipped every two weeks  Excellent mass resolution  Particle ID: p, K and  by dE/dx and TOF  L1 trigger on displaced two-track objects W. Taylor, APS/AAPT 2010 5

6. Flavour-changing neutral current decays are highly suppressed in the SM as they do not occur at tree-level (i.e., lowest order)Flavour-changing neutral current decays are highly suppressed in the SM as they do not occur at tree-level (i.e., lowest order) New physics (e.g., SUSY, technicolour, 4 th generation*) might occur in internal loopsNew physics (e.g., SUSY, technicolour, 4 th generation*) might occur in internal loops –Could enhance the branching fractions significantly –Could also affect the angular distributions W. Taylor, APS/AAPT 2010 6 B (u,d,s) →  +  - h FCNC Decays * W.-S. Hou et al., PRD 76 016004 (2007)

7. B (u,d,s) →  +  - h Decays Trigger on two muons in 4.4 fb -1Trigger on two muons in 4.4 fb -1 Final offline selection uses neural networkFinal offline selection uses neural network Use unbinned maximum log-likelihood fit to invariant massUse unbinned maximum log-likelihood fit to invariant mass CDFnote 10047CDFnote 10047 W. Taylor, APS/AAPT 2010 7 8.5  9.7  6.3 

8. B (u,d,s) →  +  - h Decays SM predicts Br ~ O(10 -6 )SM predicts Br ~ O(10 -6 ) Use as normalization channel for branching fraction to avoid many systematic uncertaintiesUse as normalization channel for branching fraction to avoid many systematic uncertainties Precision competitive to world average values:Precision competitive to world average values: First ever measurement:First ever measurement: –The rarest measured B s 0 decay! –Theoretical prediction of 1.61  10 -6 (Geng and Liu, J.Phys.G29:1103-1118,2003) agrees well W. Taylor, APS/AAPT 2010 8

9. B 0 →K *0  +  - Decays K *0 forward-backward asymmetry A FBK *0 forward-backward asymmetry A FB –  µ is helicity angle between µ + direction and the opposite of the B direction in the dimuon rest frame K *0 longitudinal polarization F L from angle  K between the kaon and the B direction in the K *0 rest frameK *0 longitudinal polarization F L from angle  K between the kaon and the B direction in the K *0 rest frame Divide data into 6 bins of q 2 =m 2 (µ + µ - )c 2Divide data into 6 bins of q 2 =m 2 (µ + µ - )c 2 W. Taylor, APS/AAPT 2010 9

10. B 0 →K *0  +  - Decays Precision is competitive with B factory measurementsPrecision is competitive with B factory measurements Experimental results are consistentExperimental results are consistent W. Taylor, APS/AAPT 2010 10 Belle SM Babar SM SM lower than data by 2.7  PRD 79, 031102(R) (2009) PRL 103, 171801 (2009)

11. W. Taylor, APS/AAPT 2010 11 B (d,s) →  +  - Rare Decays SM expected limits:SM expected limits: –Br(B d →  +  - )<(1.000.14)x10 -10 ~|V td | 2 –Br(B d →  +  - )<(1.00±0.14)x10 -10 ~|V td | 2 –Br(B s →  +  - )<(3.860.57)x10 -9 ~|V ts | 2 –Br(B s →  +  - )<(3.86±0.57)x10 -9 ~|V ts | 2 New physics could introduce tree-level contributionsNew physics could introduce tree-level contributions –can enhance the branching fraction by x100 over the SM prediction

12. B (d,s) →  +  - Rare Decays Utilize muons with |  | 2.0 GeV/cUtilize muons with |  | 2.0 GeV/c Boosted decision treeBoosted decision tree –B-candidate decay length significance –B-candidate p T –B-candidate track isolation –Impact parameter significance –Vertex  2 probability Assume no contribution from B d →  +  - (|V td /V ts | 2 ~0.04)Assume no contribution from B d →  +  - (|V td /V ts | 2 ~0.04) DØnote 5906DØnote 5906 W. Taylor, APS/AAPT 2010 12

13. B (d,s) →  +  - Rare Decays Utilize muons with |  | 2.0 GeV/cUtilize muons with |  | 2.0 GeV/c Muons form B-candidate vertexMuons form B-candidate vertex Neural-net variablesNeural-net variables –B-candidate decay length and significance –B-candidate track isolation –Opening angle between B- candidate momentum and decay length –p T (B) and p T (µ Low ) CDFnote 9892CDFnote 9892 W. Taylor, APS/AAPT 2010 13

14. W. Taylor, APS/AAPT 2010 14 B (d,s) →  +  - Rare Decays At 95% CL in 3.7fb -1 : Br(B d →  +  - )<7.6x10 -9 Br(B s →  +  - )<4.3x10 -8At 95% CL in 3.7fb -1 : Br(B d →  +  - )<7.6x10 -9 Br(B s →  +  - )<4.3x10 -8 Expected upper limit in 5fb -1 : Br(B s →  +  )<5.3x10 -8 (95% CL)Expected upper limit in 5fb -1 : Br(B s →  +  )<5.3x10 -8 (95% CL)

15. B (d,s) →  +  - Rare Decays Enhancements over SM greater than ~10x already excludedEnhancements over SM greater than ~10x already excluded Combined Tevatron expected limits may reach 4x with 8fb -1Combined Tevatron expected limits may reach 4x with 8fb -1 Stay tuned!Stay tuned! W. Taylor, APS/AAPT 2010 15 NP?

16. W. Taylor, APS/AAPT 2010 16 Upsilon Polarization Non-Relativistic Quantum Chromodynamics (NRQCD)Non-Relativistic Quantum Chromodynamics (NRQCD) –QQ production is perturbative short-distance process –Hadronization into  is long-distance process, which is expanded in powers of heavy quark velocities Past CDF measurements of J/  and  (2s) polarization do not agree with NRQCDPast CDF measurements of J/  and  (2s) polarization do not agree with NRQCD Reconstruct  (1s)→  +  - decaysReconstruct  (1s)→  +  - decays In the  rest frame,  + makes an angle  * with respect to the  direction in the lab frameIn the  rest frame,  + makes an angle  * with respect to the  direction in the lab frame  =  1 for fully longitudinal polarization  =  1 for fully longitudinal polarization  = +1 for fully transverse polarization  = +1 for fully transverse polarization

17. W. Taylor, APS/AAPT 2010 17 Upsilon Polarization Apply simulated trigger conditions and offline cutsApply simulated trigger conditions and offline cuts Get templates reflecting how fully polarized events would appear in the detectorGet templates reflecting how fully polarized events would appear in the detector Dimuon trigger: p T (  1 )>4GeV/c, p T (  2 ) >3GeV/c,  4GeV/c, p T (  2 ) >3GeV/c,  <0.6; Offline: require good dimuon vertex, with mass consistent with  (1s) Generate MC samples with fully transverse and fully longitudinal polarizationsGenerate MC samples with fully transverse and fully longitudinal polarizations

18. W. Taylor, APS/AAPT 2010 18 Upsilon Polarization Determine polarization parameter by matching a polarization-weighted combination of templates to the  *(  + ) distributions in the data in each of eight p T (  ) binsDetermine polarization parameter by matching a polarization-weighted combination of templates to the  *(  + ) distributions in the data in each of eight p T (  ) bins Apparent disagreement with NRQCD and DØ resultApparent disagreement with NRQCD and DØ result Look forward to new DØ J/  and  polarization resultsLook forward to new DØ J/  and  polarization results

19. W. Taylor, APS/AAPT 2010 19 CP Violation Violation of the Charge-Parity SymmetryViolation of the Charge-Parity Symmetry Charge symmetry: matter  antimatterCharge symmetry: matter  antimatter Parity symmetry: like a mirror symmetry but in 3DParity symmetry: like a mirror symmetry but in 3D

20. W. Taylor, APS/AAPT 2010 20 CP Violation Violation of the Charge-Parity SymmetryViolation of the Charge-Parity Symmetry Charge symmetry: matter  antimatterCharge symmetry: matter  antimatter Parity symmetry: like a mirror symmetry but in 3DParity symmetry: like a mirror symmetry but in 3D Large sources of CP violation would explain the observed matter-antimatter asymmetry of the universeLarge sources of CP violation would explain the observed matter-antimatter asymmetry of the universe

21. B s 0 mixing:B s 0 mixing: If, an excess of B s 0 would “build up”  CP violationIf, an excess of B s 0 would “build up”  CP violation Search for a charge asymmetry in decays versus decaysSearch for a charge asymmetry in decays versus decays CP Violation in B s 0 Mixing W. Taylor, APS/AAPT 2010 21 Antimatter Matter

22. CP Asymmetry in B s 0 Semileptonic Decays Need to correct for detector asymmetriesNeed to correct for detector asymmetries –Muon toroid polarity flip Use decay time informationUse decay time information Tagging mixed versus unmixed decays helpsTagging mixed versus unmixed decays helps W. Taylor, APS/AAPT 2010 22 arXiv:0904.3907

23. CP Phase  s in B s 0  J/  Decays Get two mass eigenstates:Get two mass eigenstates: SM predictsSM predicts New physics (e.g., 4 th generation) could contribute a large phase  s NPNew physics (e.g., 4 th generation) could contribute a large phase  s NP Use B s 0  J/  decays: golden mode Use B s 0  J/  decays: golden mode –yield both CP-even and CP-odd final states, which have different angular distributions Can separate the CP components via a time- dependent angular analysis of decay productsCan separate the CP components via a time- dependent angular analysis of decay products 23 W. Taylor, APS/AAPT 2010

24. CP Phase  s in B s 0  J/  Decays W. Taylor, APS/AAPT 2010 24 DØnote 5928 CDFnote 9787 2.12  For large  s NP :

25. CP Phase  s with A SL Constraint 25 W. Taylor, APS/AAPT 2010 A s sl =ΔΓ s /Δm s tan(  s )

26. B spectroscopy measurements provide sensitive tests of potential models, heavy quark effective theory (HQET), and lattice gauge theoryB spectroscopy measurements provide sensitive tests of potential models, heavy quark effective theory (HQET), and lattice gauge theory W. Taylor, APS/AAPT 2010 26 b Baryons b-b- b-b-

27. Reconstruct 848  93  b 0  c +  -  +  - events where  c +  pK -  + in 2.4 fb -1Reconstruct 848  93  b 0  c +  -  +  - events where  c +  pK -  + in 2.4 fb -1 Observe resonant structures:Observe resonant structures: –  b 0  c (2595) +  -   c +  -  +  - –  b 0  c (2625) +  -   c +  -  +  - –  b 0  c (2455) ++  -  -   c +  -  +  - –  b 0  c (2455) 0  +  -   c +  -  +  - Measure branching fractions relative to  b 0  c +  -  +  -Measure branching fractions relative to  b 0  c +  -  +  - Compare theoretical predictions to measured branching fractions to test heavy quark effective theory (HQET)Compare theoretical predictions to measured branching fractions to test heavy quark effective theory (HQET) Important for measurement of Br(  b 0  c +  - )Important for measurement of Br(  b 0  c +  - ) Resonant Structure in  b 0  c +  -  +  - W. Taylor, APS/AAPT 2010 27

28. Resonant Structure in  b 0  c +  -  +  - Sample collected by the impact- parameter triggerSample collected by the impact- parameter trigger Look for resonances with respect to M(  c + )Look for resonances with respect to M(  c + ) Veto  c * resonances for  c * searchVeto  c * resonances for  c * search W. Taylor, APS/AAPT 2010 28

29. Resonant Structure in  b 0  c +  -  +  - W. Taylor, APS/AAPT 2010 29

30.  b - (ssb) Baryon Observation Use J/  µ + µ - sampleUse J/  µ + µ - sample Need to reconstruct three decay verticesNeed to reconstruct three decay vertices DØ uses BDT selection, unbinned likelihood mass fit and  b -  J/   - decays for many cross-checksDØ uses BDT selection, unbinned likelihood mass fit and  b -  J/   - decays for many cross-checks CDF uses a cut-based selection with B 0  J/  K *0 and B 0  J/  K s 0 decays for cross-checksCDF uses a cut-based selection with B 0  J/  K *0 and B 0  J/  K s 0 decays for cross-checks W. Taylor, APS/AAPT 2010 30

31.  b - (ssb) Baryon Observation W. Taylor, APS/AAPT 2010 31  M=|M D0 -M CDF |~6  4.2fb -1 M(  b - )=6054.4  6.8(stat)  0.9(syst) MeV/c 2 PRD 80, 072003 (2009) M(  b - )=6165  10(stat)  13(syst) MeV/c 2 PRL 101, 232002 (2008) S. Godfrey, DPF 2009 Proceedings

32. CDF and DØ measurements of the  b - mass agreeCDF and DØ measurements of the  b - mass agree –DØ: M(  b - )=5774  11(stat)  15(syst) MeV/c 2 (PRL 99, 052001 (2007)) –CDF: M(  b - )=5790.9  2.6(stat)  0.9(syst) MeV/c 2 DØ is performing new analysis with 5 x dataDØ is performing new analysis with 5 x data –Half the new sample includes the new Layer 0 silicon detector CDF could at best double its dataset, but could also include additional channelsCDF could at best double its dataset, but could also include additional channels Stay tuned!Stay tuned!  b - (ssb) Baryon Observation W. Taylor, APS/AAPT 2010 32

33. W. Taylor, APS/AAPT 2010 33Conclusions The Tevatron experiments are very active in B physics and things are getting interesting!The Tevatron experiments are very active in B physics and things are getting interesting! –CDF/DØ  polarization –CDF/DØ  b - mass –CP violation in B s 0  J/  –B s 0 →  +  - Tevatron is funded to run through 2011  10fb -1Tevatron is funded to run through 2011  10fb -1 –Need to improve analysis techniques too Can expect many improved results and maybe new discoveries in the next two years!Can expect many improved results and maybe new discoveries in the next two years!