2. Outline Detectors and Methods –Spectrometer layout –Segmented target, OOT cut effectiveness –CITADL Kaonicity pion ID effect on K-pi reflection –Target Silicon –Vertexing and skim strategy –Omega signal EM Calorimeters & Muon Upgrades –IE & OE pi0 reconstruction –D*-D mass –Semileptonic Physics Form Factor Measurement D0-D0bar mixing FOCUS Physics –K K Ks Dalitz –DCSD : D+ -> KKK –Charm baryon signals CascadeC -> p k pi LambdaC -> sigma pi pi –Double-D Production –K K pi Dalitz –D lifetimes CP Violation and Mixing –D0 CP eigenstate lifetime diffs. CLEO plots FOCUS Advantages K-pi signal Skim Strategy (candidate-driven) –CP asymmetry (Daniele) –CP asymetry (O’Reily)

3. Segmented Target Decays/200  m BeO tarsil black - primary vertex red - secondary vertex 62% of D decays occur in air Out-of-Material cut virtually eliminates non-charm backgrounds From background subtracted charm!

4. D + Yield= 11528 S/N= 2.8 D  KK  D + Yield= 7157 S/N= 10 Out of Material

5. “Kaonicity” Golden Kaons & pions Likelihood based Cerenkov algorithm

6. D +   +  - without Cerenkov ID K  reflection  signal

7. D +   +  - with loose pion ID Yield = 3317

8. D +   +  - with tight pion ID Yield = 2092

9.  0 reconstruction with the IE and OE (with D* tag) D 0  K -  +  0

10. D 0  K -  +  0 has a rich substructure with lots of interference

11. Target Silicon Detector Proper time resolution vs run number TS used No TS TS installed Target Silicon detector improves proper time resolution by about 20%

12. D*-D Mass Difference Measurements These measurements hilight our improved  0 reconstruction Statistical errors should be about 3 times better than present world average

13. Charm Baryon Signals Cabibbo suppressed decay mode of the (first observed by SELEX)

15. Expected resonance contributions to D 0  KKK S Class 1 BSW requires resonance coupling to u- dbar quarks and a dikaon. The only resonances are: a0 (980) (sub-threshold) a2 (1320) Class 2 BSW requires resonance coupling to u- ubar quarks and a dikaon: f0 (980) (subthreshold) f2 (1270)

16. Dalitz Analyses

17. FOCUS Semileptonic Physics Measure Form Factors for –Check against recent LGT calculations Cabibbo suppressed decays: Semileptonic mixing: Rare or forbidden decays: Expect roughly 50 times more semimuonic events than E687 with our rebuilt muon system!

18. — Right Sign — Wrong Sign RS-WS yield  56445

19. D0 CP eigenstate Lifetime Differences CLEO assumi ng CP CLEO allowin g CP violatio n  MM

20. FOCUS can make competitive  measurement Y=16532 STN=2.3 Expect  y =1.3% (  y (CLEO) = 1.73%) M(KK)

21. Extremely good proper time resolution :    8%  (D 0 ) –No resolution systematics or error inflation A segmented target with ~62% of decays verticizing in air – Grossly minimizes absorption corrections in matter Excellent (and flexible) Cerenkov identification –Vary misidentification reflections to gauge systematics. Skims use a vertexing algorithm with nearly flat t’ acceptance –Minimizes any reliance on MC and reduces systematic error We expect to measure y to within 1.3% FOCUS ADVANTAGES

22. Skim Strategy with minimal time bias K K Seed track Primary vtx track Recoil charm track Nearly uniform time acceptance --right up to the skim cut! Nucleate about seed track to form a primary vertex. Look for two tracks with a good intersection A minimum bias skim for D 0  KK

23. CP Violation Search in D + and D 0 Decays Asymmetry mechanism in Pythia Need to correct for production asymmetry which occurs at ~3% level

24. Expectin g 1-2% sensitivit y

26. Doubly Cabibbo Suppressed Decays D Peak D S Peak  D = 8.5 MeV/c 2  D S = 8.5 MeV/c 2

27. Double D Photoproduction Dynamics Charm and anticharm acoplanarity distribution probes NLO QCD The correlation between a charm particle and an anticharm particle in the same event  radians)  :  kinematic tag  : Double D reconstruction ~