1. Z c decay width in QCD sum rules University of São Paulo F.S. Navarra Peñiscola 27/05/2013 Dias, Navarra, Nielsen, Zanetti, arXiv:1304.6433 New states in the charmonium spectrum Z c decay width

2. Before 2003: Cornell potential: Introduction “Good” quarkonium spectrum States with “wrong” masses After 2003: Schrödinger equation:

3. Isospin violation: Charged states: (2003) (2007)

4. Ten years of “bad behavior” * * (2013) BES-III BELLE CLEO c *

5. What is the structure of the new states ? Tetraquark Meson molecule Hybrid cc c c Hadro-charmonium New questions

6. Maiani (2005) X(3872) must have a charged partner Maiani (2007) Z + (4430) is its first radial excitation ! What is the relation between them ?

7. Maiani,Polosa,Riquer, arXiv:0708.3997 2013 Navarra,Nielsen,Richard, arXiv:1108.1230

8. Z c decay width X (3872) < 2.3 Z c (3900) ~ 50

9. Two body decay Phase Space

10. Amplitude A comes from the Lagrangian How do we know the coupling constant ? Example:

11. QCD sum rules hadrons quarks Coupling constants in QCD sum rules

12. The OPE side Z c = diquark – antidiquark …

13. Problem: it is very difficult to separate a diquark-antidiquark from a meson-meson current ! Fierz transformation mesons diquarks

14. Tetraquark has color entanglement. How to enforce it ? Require color exchange during the decay ! Color-connected diagrams

15. The phenomenological side Insert complete sets of states into Define ?

16. Choose the structure: Input numbers: Coupling constant:

17. Results Total width 29 19 4 4 Maiani (2013)

18. Summary Z c is the charged partner of X (3872) Tetraquark approach reproduces the mass and the decay width

19. 2003: X(3872) 2013: Z + (3900) Ten years of “bad behavior”

20. How to group the new states ? Gell-Mann fifties, sixties… 150

21. Problem: it is very difficult to separate a diquark-antidiquark from a meson-meson current ! Fierz transformation mesons diquarks

25. I knew ! I just know !