Size of direct CP violation in singly Cabibbo-suppressed D decays

作者：Brod Joachim^*; Kagan Alexander L; Zupan Jure

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2012, 86(1): 014023.

DOI：10.1103/PhysRevD.86.014023

The first experimental evidence for direct CP violation in charm-quark decays has recently been presented by the LHCb collaboration in the difference between the D -%26gt; K+K- and D -%26gt; pi(+)pi(-) time-integrated CP asymmetries. We estimate the size of the effects that can be expected within the Standard Model and find that at leading order in 1/m(c) they are an order of magnitude smaller. However, tree-level annihilation type amplitudes are known to be large experimentally. This implies that certain formally 1/m(c)-suppressed penguin amplitudes could plausibly account for the LHCb measurement. Simultaneously, the flavor-breaking parts of these amplitudes could explain the large difference between the D -%26gt; K+K- and D -%26gt; pi(+)pi(-) decay rates.

• 出版日期2012-7-23