1. Julia Thom, FNALEPS 2003 Aachen Rare Charm and B decays at CDF Julia Thom FNAL EPS 7/18/2003 Tevatron/CDF Experiment Decay Rate Ratios and CP Asymmetries of Cabibbo suppressed D 0 decays Search for D 0 →  Search for B 0 s,d → 

2. Julia Thom, FNALEPS 2003 Aachen The Tevatron Main Injector (new) Tevatron DØCDF Chicago   p source Booster Tevatron Upgrade: Higher Bunch Crossing Rate: 396 ns 5-10 higher target lumi than RunI Higher C.o.M Energy RunI:1.8 TeV RunII:1.96 TeV

3. Julia Thom, FNALEPS 2003 Aachen Tevatron Performance Record lumi.: 4.5 10 31 cm -2 s -1 (~factor 2 better than RunI) Improving slowly 4-7 pb -1 per week For CDF: Current:~200 pb -1 to tape For this talk: ~65pb -1 w/all important Systems on (Feb.2002-Feb2003) delivered To tape Delivered To tape

4. Julia Thom, FNALEPS 2003 Aachen The CDF Run II Detector New DAQ Track based trigger at L1 (XFT) Impact parameter trigger at L2 (SVT) (by far most important upgrade for B and charm) New Silicon system –7-8 layer silicon detector (up to |  |~2) Improved b-tagging Extended muon systems (to |  |~1.5) Time of flight detector(particle ID) New central drift chamber –Detector upgrades give new charm and bottom physics program –Charm Results already competitive with world’s best

5. Julia Thom, FNALEPS 2003 Aachen Silicon Vertex Trigger Includes ~33  m beamspot  =47  m Online IP resolution from SVT Level 1 track trigger: high p t Level 2 track trigger: large d 0 Improves RunI sensitivity by 4-5 orders of magnitude CDF as “Charm Factory” ~million D 0 ’s per 100 pb -1 Triggers used in this talk: Two track trigger 2 tracks p t >2GeV, d 0 >120mm,  p t >5.5 GeV Rare B trigger 2 muons with momentum/vertexing requirements

6. Julia Thom, FNALEPS 2003 Aachen Decay Rate Ratios of Cabibbo Suppressed D0 Decays TH: R(KK/  )<1.4 Ex: ~2.5 (world average) (difference prob. due to FSI) Many systematics (trigger, reconstruction..) cancel in ratio Relative acceptance estimated from MC + realistic simulation

7. Julia Thom, FNALEPS 2003 Aachen Use triggered track pairs Combine D 0 with soft  for D* No particle ID D*/D0 Signal Extraction Selection cuts: D 0 Impact Parameter 5.5 GeV D 0 L xy >350  m m(D*)-m(D 0 ) 3  around expexted value Extract number of signal&bkg events from fits : 93560 D*→D 0  →[K  8320 D*→D 0  →[K  3697 D*→D 0  →[ 

8. Julia Thom, FNALEPS 2003 Aachen Monte Carlo Input Relative Acceptance Corrections from MC Different efficiencies due to: Nuclear Interactions of K/ , K + /K - ,K decay length trigger bias (due to different opening angle) Using realistic detector simulation:

9. Julia Thom, FNALEPS 2003 Aachen Decay Ratios: Results  (D 0  KK)/  (D 0  K  = 9.38  0.18(stat)  0.10(syst) %  (D 0   )/  (D 0  K  = 3.686  0.076(stat)  0.036(syst) % Competitive with FOCUS 2003:  (D 0  KK)/  (D 0  K  = 9.93  0.14  0.14 %  (D 0   )/  (D 0  K  = 3.53  0.12  0.06 %

10. Julia Thom, FNALEPS 2003 Aachen CP asymmetries of Cabibbo Suppressed D 0 decays TH: O(10 -3  10 -2 ) NP can enhance the CP-violation rate Soft  charge tags D 0 flavor: q(  soft )>0: D 0 q(  soft )<0:D 0 bar Need to correct observed asymmetries for intrinsic charge asymmetry of CDF detector (soft tracks) Study charge asymmetry as a function of soft  p t

11. Julia Thom, FNALEPS 2003 Aachen Charge Asymmetry in the CDF Detector Study asymmetry using unbiased tracks and correct Residual asymmetry syst.error (Expect no CP asymmetry) (same track quality cuts generic track sample)

12. Julia Thom, FNALEPS 2003 Aachen CPV: Results  CP (D 0  KK) = 2.0  1.7 (stat)  0.6 (syst) % A CP (D 0   ) = 3.0  1.9 (stat)  0.6 (syst) % CLEO results: Plan: redo analysis for 8-10 times statistics

13. Julia Thom, FNALEPS 2003 Aachen Search for FCNC D 0 →  SM expectation BR~ 3*10 -13 Best limit: <4.1x10 -6 (90% CL) (Beatrice/WA92, E771) BR significantly enhanced with New Physics (e.g. R-Parity Violation Susy: ~3.5*10 -6 ) Events from two-track trigger use first 63pb -1 of data Normalize to D 0 →  to cancel acceptance and trigger effects Only relative efficiency needed

14. Julia Thom, FNALEPS 2003 Aachen Normalization Mode: D 0 →  Search window: 1.84<m<1.884 GeV Selection: intersect D 0 with soft  0.144<m(D*)-m(D 0 )<0.147 Optimized cuts: L xy <0.45 cm, |d xy |<0.015cm, Angle cut between track and muon stub, Track quality cuts N(  ) = 1371  53 Relative efficiency from Monte Carlo: ( muon reconstruction and  decay in flight efficiency) KK

15. Julia Thom, FNALEPS 2003 Aachen Background Fakes from  misidentification: N( D 0 →  ) in mass window times (misid probability) 2 : Estimate combinatorics from high mass sideband where both tracks are muons Fakes: 0.22  0.02 eventsCombinatorics:1.5  0.7 events From D* tagged D 0 →   misid probability

16. Julia Thom, FNALEPS 2003 Aachen FCNC D 0 →  : Results BR( D 0 →  )<2.4x10 -6 (90% CL) Factor 2 improvement over best limit M(  ) with D* tag and 2 muons 1.7 expected events, 0 observed events: N cl =2.3 Next: use full muon coverage and 2-3 times more data (~1year) also look at D + →  D + →K  D 0 →  e, D s

17. Julia Thom, FNALEPS 2003 Aachen Search for FCNC B s,d →  BR( B s 0 →  )~10E-9 in SM Best published limit:2.6 10E-6 at 90% C.L.(CDF) Can be enhanced by >2 orders of magnitude in SUSY scenarios Particular interest: hand in hand with deviations of (g-2)   hep-ph  Relevant part predicts 10 -7 :10 -8 Observable in Run II If true, m(h)~120 GeV Lots of theoretical interest

18. Julia Thom, FNALEPS 2003 Aachen B s →  search method Acceptance estimated from MC (|y(B)| 6 GeV), Trigger and reconstruction efficiency from data Analysis cut efficiency from MC (x-check with B + →J/Psi data) B s cross-section: assume B d :B s 3:1 Discriminating variables: Dimuon Inv.mass (m   around PDG  Lifetime (c  m  Pointing angle (  phi  rad  Isolation of Bs candidate (iso>0.65)

19. Julia Thom, FNALEPS 2003 Aachen Background Estimate background from sideband (Heavy flavor contr. <10 -9 ) If correlations between cut variables small Factorize background estimate Background: 0.57 +- 0.22 events

20. Julia Thom, FNALEPS 2003 Aachen B s →  Sensitivity Current estimated sensitivity optimized cuts and 65 pb-1 of data: BR(B s →  ) < 2.4 10 -6 RunI limit:2.6 10 -6 BR(B d →   not opened the box yet, will include 2-3 times the data and full muon coverage soon

21. Julia Thom, FNALEPS 2003 Aachen Conclusions First Results on Rare Charm (and B) decays at CDF Decay ratios and CPV of Cabibbo suppressed D 0 decays already competitive/best sensitivity FCNC searches: best limits D 0 →  factor 2 improvement over best publ. limit B s →  expect to improve RunI limits soon!