1. Physics of the Charm Quark Gene Golowich Physics Department Univ. of Massachusetts Amherst MA Colloquium Wayne State Univ. September 22, 2005

2. Rough Outline Some Background Comments Some Standard Model Some New Physics

3. ‘Coals to Newcastle’ Experiment CLEO: Bonvicini, Cinabro, Dubrovin CDF: Harr, Karchin Theory Petrov, Gabbiani, AlFiky

4. Discovery of Charm Age: c-quark will turn 31 on 11/11 Birth: East Coast (BNL) West Coast (SLAC) SLAC Method: Narrow resonance at E = 3.1 GeV! Thereafter called the `J/  ’

5. The Standard Model

6. NuTeV Anomaly?

7. Three Years of Tests

8. Spectrum of Quark Masses Predict this Spectrum: Easy/Hard?

9. Quark Masses and Theory Predict quark masses? No viable models exist What about String Theory? String ground state huge! `Landscape’ description. Many-universes scenario. Elementary constants random! Lucky us! We EXIST!! What about m c = 1.3 GeV? Difficult theoretically. Not heavy enough! Not light enough! Complications of QCD

10. QED vs QCD QED QCD

11. Progress in Lattice QCD

12. Standard Model Physics D Meson Ground State The spectator c-quark: B c Mesons D Decays: Leptonic, Semileptonic, Nonleptonic Spectroscopy: Exotic states?

13. D Meson Ground State Predict the States: Easy/Hard?

14. D Meson Ground State q = u  D 0 q = d  D + q = s  D s + Easy! 3 * of SU(3)

15. Flavored Mesons Each quark has its own ‘flavor’ Quark composites are ‘flavored’ s-quark: K’s = c-quark: D’s = b-quark: B’s = The t-quark decays too quickly!

16. B c Mesons!

17. Leptonic Decay of D + Decay Amplitude: Decay Constant f D : Non-perturbative efect. Requires Lattice QCD!

18. f D : Theory vs Experiment

19. Semileptonic Decays Decay Amplitude: D 0  K e + e

20. Form Factor Slopes

21. Nonleptonic Decays Decay Amplitude: A = a e i 

22. Dalitz Studies

23. Phase Information

24. More Dalitz

25. Comparative Lifetimes B: B - = b B 0 = d  - /  0 = 0.92

26. Comparative Lifetimes B: B - = b B 0 = d  - /  0 = 0.92 D: D 0 = c D + = c  - /  0 = 2.55

27. Comparative Lifetimes B: B - = b B 0 = d  - /  0 = 0.92 D: D 0 = D + =  - /  0 = 2.55 K: K - = K 0 =  - /  0 = 139.

28. Charm Production e+e- collisions produce charm. There are predictions for this. Not all data are understood!

29. Heavy Meson Spectroscopy

30. X(3872) Sighting

31. Is X(3872) a Molecule? AlFiky, Gabbiani, Petrov (2005) [plus others] Interpret X(3872) as a bound state of hadrons ( ) Analogous to the Deuteron! Similar molecular state predicted long ago. Beware: other interpretations possible.

32. Y(3940)  2 /d.o.f. = 15.6/8 stat. sig. = 8.1   above D*D threshold  not found in DD or D*D final states

33. Is Y(3940) a ‘Hybrid’? Hybrid Meson : Color-octet quark-antiquark couples to color-octet gluon to yield color-singlet hadron

34. D 0  K -  +

35. Where are CP Violations?

36. New Physics and Charm Methodology? Rare Decays of D Mesons Flavor Oscillations CP Violations (not discussed here)

37. Methodology How to find ‘New Physics’? Study systems where SM signals are small. Ideal for charm: A] Rare Decays B] Flavor Oscillations

38. D 0   +  - in the SM

39. Data and D 0   +  -

40. D 0   0 e + e -

41. Flavor Oscillations Mixing Mixing also in K 0,B d and B s. Each of these is different!

42. Two Coupled Penduli

43. The ‘Spring’

44. New Physics and Mixing

45. The Normal Modes Normal Modes Effect of CP: CP EigenstatesCP Eigenstates

46. Mixing of B d Mesons

47. Mixing of B s Mesons

48. Mixing of K Mesons

49. Mixing of D 0 Mesons

50. Recent Work on D 0 Mixing Theory: Effect of QCD incorporated into analysis of D 0 mixing by Golowich and Petrov. Work continues. Experiment; Especially interesting are attempts to measure  D at the 1% level.

51. Summary I The c-quark is a remarkably spry 31 year old! A very active social life: Spectroscopy Flavor oscillations Rare decays CP violation searches After studies at CDF, CLEO, Belle and BaBar will come the long awaited LHC.

52. Summary II Flavor mixing of D mesons will be a hot topic for both experimenters and theorists. Exotic charm states (hybrid and/or molecular) will continue to attract much attention.