1. Lifetime of doubly charmed baryons
Chao-Hsi Chang(ITP), Tong Li(NKU), Xue-Qian Li(NKU), Yu-Ming Wang(NKU)
Introduction
Formulation for Lifetimes of
Evaluation of Hadronic Matrix Elements
Numerical Results
Summary

2. Introduction
(ccd) observed by SELEX Collaboration at FERMILAB (PRL89,112001(2002))
Previous works on doubly heavy-quark baryon
(PRD60,014007(1999); hep-ph/ ; Eur.Phys.J.C9,213(1999))
WE/WA and PI mechanism(PLB280,271(1992); PLB293,430(1992); Nucl.Phys.B399,441(1993))
Hadronic wave function

3. Formulation for Lifetimes of
The general formula for inclusive decay width (lifetime): optical theorem
OPE of matrix element

4. Spectator Contribution
The total decay width can be decomposed into two parts:
Spectator contribution can be decomposed into two components:
The semileptonic and nonleptonic decay of spectator contribution have been calculated by many authors. (Bigi et al., hep-ph/ ; PRD56,2783(1997); PRD64,014003(2001))

5. Non-spectator Contribution
Effective Lagrangian
Our calculation includes CKM-suppressed contribution.

6. The inclusive decays of (ccd)

8. The inclusive decays of (ccu)

10. The inclusive decays of (ccs)

12. Hadronic Matrix Elements
Sandwiching the operators between initial and final states of forward scattering, we obtain the hadronic matrix elements:

13. Harmonic oscillator wave function

14. The decay widths

17. Numerical Results Input parameters
(PRD60,014007(1999); hep-ph/ ; Eur.Phys.J.C9,213(1999))

18. Non-perturbative parameters
reflects the coupling of the two c quarks,
we adopt the parameter the same as J/ψ
reflects the coupling of two c quarks and the light quark (u, d, s), we adopt the parameter the same as D meson

22. Compare with other work
Lifetime of
strongly depend on the wavefunction
at the origin.
hep-ph/

23. Summary Doubly charmed baryons Inclusive decay width
optical theorem, OPE, WE/WA and PI mechanism
Others (wave functions, other doubly heavy-quark baryons, triply heavy-quark baryon……)

24. Thank You!