ar X iv : h ep - p h / 01 11 24 9 v 1 2 0 N ov 2 00 1 TTP
نویسنده
چکیده
Radiative decays of B-mesons, such as B → Kγ or B → ργ provide important tests of the Standard Model and of new physics scenarios. However, besides the dominant pointlike b → sγ or b → dγ transitions generated by loops of heavy particles, there are ordinary weak decay mechanisms. In particular the decay B → ργ can proceed via the usual four-Fermi weak transition accompanied by a photon radiated from the quarks inside the initial or final mesons. Clearly, this “weak annihilation” mechanism depicted in Fig. 1 must be under theoretical control in order to predict the decay rate with a reasonable accuracy. In recent years, several calculations of the weak annihilation contribution to B → V γ were reported . Various techniques, from quark models and effective Lagrangians to dispersion relations and QCD sum rules were used.
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تاریخ انتشار 2001