Lifetime of doubly charmed baryons

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

2. Introduction • (ccd) observed by SELEX Collaboration at FERMILAB (PRL89,112001(2002)) • Previous works on doubly heavy-quark baryon (PRD60,014007(1999); hep-ph/9912424; 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/9401298; 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/9912424; 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 Lifetime of Lifetime of strongly depend on the wavefunction at the origin. hep-ph/9912424

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!