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

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

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

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))

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

The inclusive decays of (ccd)

The inclusive decays of (ccu)

The inclusive decays of (ccs)

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

Harmonic oscillator wave function

The decay widths

Numerical Results Input parameters (PRD60,014007(1999); hep-ph/9912424; Eur.Phys.J.C9,213(1999))

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

Compare with other work Lifetime of strongly depend on the wavefunction at the origin. hep-ph/9912424

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……)

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