1. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 1/16 B 0 (s)  h + h’ - decays at CDF HEP2005 International Europhysics Conference on High Energy Physics July 21 st – 27 th, 2005 – Lisboa, Portugal Diego Tonelli tonel@fnal.gov Istituto Nazionale di Fisica Nucleare, Pisa for the CDF Collaboration

2. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 2/16 Motivation Joint study of B 0 and B 0 s 2-body decays into charged kaons and pions (KK,  and K  ): a privileged insight into flavor physics and a useful tool in searching for New Physics. CDF has simultaneous access to both B 0 /B 0 s  h + h' - decays:  flavor physics program complementary to Y(4S). R. Fleischer PLB459:306-320, 1999 - constrain hadronic unknowns with SU(3) symmetry. Use approximated s  d quark symmetry (i.e. measure jointly B 0 and B 0 s ) to extract phase . WEAK amplitude theoretically clean HADRONIC/ EW theoretically uncertain TREEPENGUIN

3. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 3/16 Motivation (cont’d) Fleischer’s method needs: time-dependent asymmetries in b- flavor tagged samples, size of SU(3) breaking, sin(2  ) and  m s CDF ultimate long term goal. Currently accessible BR can constrain theory too: compare CDF measurements with allowed regions in spaces of B 0   +  - and B 0 s  K + K - observables (Y(4S) and theory): a probe for both  and NP Fleischer and Matias PRD66: 054009,2002 - London and Matias PRD70:031502, 2004. …many other interesting measurement, e.g.  s /  s in B 0 s  K + K - see talk by M. Donega’ - Friday 17.08 Room 5.

4. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 4/16 Experimental challenge #1: write signal events to tape S/N at production ~10 -9 ; high track multiplicity per event; generic final states (2 tracks, K and/or  ) in huge QCD BCKG. Crucial role of trigger: Reconstruct silicon tracks online. Trigger on displaced secondary vertices with ~30  m impact parameter (IP) resolution. B Primary vertex Secondary vertex PLANE  TO THE BEAM IP(B) IP(h 1 ) p T (h 1 ) p T (h 2 ) p T (B) large  (B)  large B decay length and IP of tracks; pp  bb + X  B from primary vertex, small IP of B.

5. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 5/16 Analysis overview SIGNAL RECONSTRUCTION unbiased optimization of the selection requirements (use MC and data) FIT OF COMPOSITION Unbinned ML fit: kinematics and dE/dx to distinguish each B 0 (s)  h + h' - mode BR RATIOS and ASYMMETRIES Correct raw fit results for trigger / selection efficiencies (use MC and data) dE/dx CALIBRATIONS Accurate calibrations of dE/dx with D* + decays CONTROL SAMPLES B 0 s and B 0 exclusive decays in J/  X and D  SIGNAL SIMULATION Realistic MC sample

6. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 6/16 Experimental challenge #2: signal extraction Unbiased optimization of selection cuts: maximize S/  (S + B) with signal from MC and background from data sidebands. isolation: fraction of p T carried by the B candidate after fragmentation. Rejects 15% of signal and 400% of background. B  -  space

7. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 7/16 Experimental challenge #3: peak composition Excellent CDF mass resolution: 5 silicon layers + drift chamber measure p T in 1.4 T solenoidal field with 132 cm lever arm  resolution ~ (0.7  0.1 p T )% Still, the four (expected) major modes overlap into an unresolved mass peak. Extract composition statistically with an unbinned 5-dimensional ML fit. Combine information from: kinematics (mass and p); particle ID (dE/dx). B 0 s modes B 0 modes simulated signals

8. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 8/16 Peak composition handle 1: kinematics  -mass vs signed momentum imbalance: (1- p min /p max )q min discriminates among modes (and flavors in K  modes). B 0   +  - + c.c. B 0 s  K + K - + c.c. B0 K-+B0 K-+ B0 K+-B0 K+- B 0 s  K +  - B0s K-+B0s K-+ MC

9. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 9/16 Peak composition handle 2: specific ionization in the drift chamber Tracks have hits in drift chamber: 96 layers, |η| ≤ 1.0; 44 cm < r < 132 cm, 30k channels; σ(hit) ~ 180 μm; dE/dx encoded in hit pulse-width. TIME OF FLIGHT Accurate, time dependent dE/dx calibration using ~95% pure K /  samples from ~70k decays: D* +  D 0  +  [K -  + ]  + + c.c. Strong D* + decay tags the D 0 flavor.

10. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 10/16 Peak composition handle 2: dE/dx (cont’d) Angle, gas pressure, time and hit- multiplicity dependences corrected. 1.4  K/  separation at p > 2 GeV/c (  60% of “perfect” separation) Residual gain fluctuations cause correlated dE/dx shifts: measured and included in the fit of composition. corrected raw corrected raw dE/dx vs  dE/dx vs hits

11. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 11/16 Raw fit results ~900 evts/180 pb -1 in initial CDF data, taken with still non optimized detector/trigger. Now much better: ~2700 / 360 pb -1 What we measure:

12. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 12/16 Efficiency/acceptance corrections Correct for relative acceptance, trigger and selection effic.: 5 -10% Kinematics and nuclear interaction efficiencies (Monte Carlo) Trigger-bias: correct for dE/dx-dependent trigger efficiency (D + data) Isolation efficiency, measured from exclusive decays (B 0 and B 0 s data)

13. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 13/16 Dominant systematic uncertainties  dE/dx track-to-track correlations (partially reduces with statistics);  B-meson masses input to the fit (reduces with statistics);  Relative isolation efficiency between B 0 s and B 0 (reduces with statistics);  Effect of final state radiation;  Trigger bias on efficiency;  Charge-dependence of dE/dx;  Background shape;  Charge asymmetries in background;  Others. (stat. ~ 7.8%) syst. ~ 1.2% (stat. ~ 17%) syst. ~ 15% (stat. ~ 24%) syst. ~ 14% (stat. ~ 29%) syst. ~ 13%

14. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 14/16 Final results: B 0 s sector B 0 s  K + K - decay established. BR ratio may favor large SU(3) breaking as predicted from sum rules (Khodjamirian et al. PRD68:114007, 2003). Allows first comparisons with Y(4S) and theory expectations, test of NP. No evidence for B 0 s  K -  +, set a limit a factor ~40 better than PDG04. Great improvement on annihilation mode B 0 s   -  +. A factor >100 below PDG04 (time-evolutions of B 0 s   -  + and B 0 s  K - K + assumed the same).

15. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 15/16 Final results: B 0 sector A CP compatible with B-factories, systematic uncertainty comparable as well, Babar statistic uncertainty just ~30% better with same sample size. With currently available data (3x statistics), we expect < 4.5% statistical uncertainty to be compared with current world best: 2.2% (Belle). Limit on pure annihilation/exchange mode B 0  K + K -. A factor ~2 above B- factories, expect much better performance on current sample. Consistent with B-factories. Valuable cross-check for other measurements.

16. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 16/16 Concluding remarks CDF has unique joint access to B 0 / B 0 s  h + h' - modes: rich physics program complementary to B-factories. Results shown ready for PRL submission in first B 0 (s)  h + h' - paper from an hadronic collider: B 0 s  K + K - decay established and BR measured (first B 0 s  PP observed); x100 improvement with respect to PDG04 on the upper limit on BR(B 0 s   +  - ) and x40 improvement on the limit on BR(B 0 s  K -  + ); measurement of A CP (B 0  K +  - ) with small systematics. Just the beginning: now 900 pb -1 on tape, of which 360 ready for analysis with ~2x increase in yield/pb -1 (optimized efficiencies), improved mass resolution (better tracking alignment and reconstruction). By end of 2005 we expect: Observe B 0 s  K -  + and reduce to ~10% statistical error on BR(B 0 s  K + K - ); A CP (B 0  K +  - ) much closer to Y(4S) with ~4% statistical uncertainty; World best limits on BR(B 0 s   +  - ) and on BR(B 0  K + K - ).

17. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 17/16 ADDITIONAL MATERIAL

18. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 18/16 The Tevatron pp collider Superconducting proton-synchrotron: 36 p  36 p bunches collision every 396 ns at √s = 1.96 TeV Luminosity…………………………….: record peak is 1.3  10 32 cm -2 s -1 ~ 10 pb -1 / week recorded on tape # interactions / bunch-crossing……..: poisson = 6 (at 2  10 32 cm -2 s -1 ) Luminous region size………………..: 30 cm (beam axis)  30  m (transverse) need long Si-vertex small wrt c  (B) ~ 450  m 2005, regularly exceeds 10 32 cm -2 s -1

19. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 19/16 Delivered Luminosity Stable data taking efficiency: ~85% The results shown here from an analysis that uses ~180 pb -1 April 2001 Feb 2002 first data for analy ses data for physics detector commiss. Jul 2002 ~ 900 pb -1 on tape 1 fb -1 milestone!

20. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 20/16 The Good bb production x-section O(10 5 ) larger than e + e - at  (4S) /Z 0. Incoherent strong production of all b-hadrons: B , B 0, B s, B c,  b,  b. The Bad Total inelastic x-section ~ 10 3   (bb). BRs’ for interesting processes O(10 -6 ). …and The Ugly Messy environments with large combinatorics. Heavy Flavor physics at the Tevatron CDF Need highly selective trigger

21. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 21/16 7-8 silicon layers 1.6< r <28 cm |z|<45 cm |η| ≤ 2.0, cosθ = 0.964 σ(hit) ~ 14 μm Time-of-flight 100 ps @150cm p, K, π id 96 layer drift chamber |η| ≤ 1.0 44 < r < 132 cm, 30k channels σ(hit) ~ 170 μm dE/dx for p, K, π id Tile / fiber endcap calorimeter 1.1 < |η| <3.5  coverage to |  |≤1.5 80% in  132 ns front end COT tracks @L1 SVX tracks @L2 30000 /300 / 70 Hz ~no dead time Some resolutions: p T ~ (0.7  0.1 p T )% J/Ψ mass ~15 MeV EM E ~ 16%/√E Had E ~ 100%/√E d 0 ~ 6+22/p T μm Primary vtx ~10 μm Secondary vtx r-Φ ~ 14 μm r-z ~ 50 μm 1.4 T magnetic field Lever arm 132 cm CDF Detector Upgrades

22. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 22/16 Triggering bs’ (and cs’) Di-lepton B  charmonium Rare B   Two muons with: p T > 1.5 GeV |  |< 1 p T > 2.5-4.5 GeV |  |<2 electron or  and displaced track Semileptonic decays Electron (  ) with: p T > 4 (1.5) GeV |  |< 1 and one track with: p T > 2.0 GeV IP > 120  m Two displaced tracks n-body hadronic B Two tracks with: p T > 2.0 GeV  p T > 5.5 GeV IP > 120 (100)  m Displaced track trigger at Level 2: a revolution in hadronic environment ! Makes it accessible rare hadronic decays with high S/B. conventionalnew approach

23. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 23/16 Systematics - detailed

24. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 24/16 Raw physics results

25. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 25/16 Raw physics results

26. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 26/16 Corrected results

27. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 27/16 Correlation matrix Legenda

28. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 28/16 p.d.f. projection: momentum imbalance

29. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 29/16 p.d.f. projection: |p(1)| + |p(2)|

30. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 30/16 p.d.f. projection: dE/dx

31. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 31/16 p.d.f. projection: dE/dx

32. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 32/16 Momentum p.d.f. pp  pp Monte Carlo Binned ML fit signal background

33. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 33/16 dE/dx model

34. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 34/16 Silicon Vertex Trigger

35. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 35/16 Silicon Vertex Trigger (cont’d) (35  33)  m SVT  beam   = 48  m SVT

36. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 36/16 B 0 s  K + K - lifetime B 0 lifetime from PDG04. B 0 s  K + K - lifetime depends on: -  s /  s : width difference between “long” and “short” eigenstates -the relative composition in short and long-lived components Assume Standard Model  s =  d and  s /  s = -0.12  0.06 B 0 s  K + K - is expected almost 100% “short-eigenstate” Fleischer and Matias:PRD66-054009,2002) Therefore the lifetime of B 0 s  K + K - is determined as:

37. HEP2005 Lisboa - July 21 st, 2005Diego Tonelli, CDF - Pisa 37/16 Physics Motivations (backup) The combination of B d and B s decays provides a promising way to extract CP-related physical parameters avoiding the “penguin pollution”. (R. Fleischer PLB459 (1999) 306) Assume U-spin symmetry (d  s), the A CP are function of the CKM angles  and  and of the amplitude ratio P/T (~ de i  )  4 equation with 4 unknowns ( , , d,  ). A combined fit of the 4 CP asymmetries measures ,  and P/T ratio. Above strategy need time-dependent analysis with tagged samples: long term goal