## Abstract

We study the novel decays B*→Bγγ and D*→Dγγ using the framework of the heavy meson chiral Lagrangian (HMχL) to leading order in chiral perturbation theory. The branching ratios of these decays are expressed in terms of the strong g_{B*(D*)B(D)π} and the electromagnetic g_{B*(D*)B(D)γ} couplings, thus providing a possible tool for their determination. In the charm case, using the experimentally determined ratios (D*^{0,+} →Dπ)/(D*^{0,+}→Dγ), we are able to express the branching ratio as a function of the strong coupling only. We thus find 1.6x10^{-6}<Br(D*^{0}→D ^{0}γγ)<3.3x10^{-5} for 0.25<g<1, where g is the strong coupling of HMχL. In the b-flavored sector, the Br(B*^{0}→B^{0}γγ) which we estimate to be in the 10^{-7}-10^{-5} range is a function of both g_{B*Bπ} and g_{B*Bγ}. Its behavior does not afford an unambiguous determination of these couplings except for the region of high g values such as g>0.6. The expected two-photon differential distributions are presented for both B*^{0}→B^{0}γγ and D*^{0}→γγ, for different values of the couplings involved.

Original language | English |
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Article number | 054014 |

Pages (from-to) | 1-10 |

Number of pages | 10 |

Journal | Physical review D |

Volume | 61 |

Issue number | 5 |

DOIs | |

State | Published - 1 Mar 2000 |

Externally published | Yes |

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