0 Ju l 2 00 1 The Rare Decay D 0 → γγ
نویسنده
چکیده
ABSTRACT We present a calculation of the rare decay mode D0 → γγ, in which the long distance contributions are expected to be dominant. Using the Heavy Quark Chiral Lagrangian with a strong g coupling as recently determined by CLEO from the D∗ → Dπ width, we consider both the anomaly contribution which relates to the annihilation part of the weak Lagrangian and the one-loop π, K diagrams. The loop contributions which are proportional to g and contain the a1 Wilson coefficient are found to dominate the decay amplitude, which turns out to be mainly parity violating. The branching ratio is then calculated to be (1.0 ± 0.5) × 10−8. Observation of an order of magnitude larger branching ratio could be indicative of new physics.
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تاریخ انتشار 2001