Abstract
The recently measured direct CP asymmetries in the processes D 0 → π + π − and D 0 → K + K − show a significant deviation from the naive Standard Model expecta- tion. Using a general parameterization of the decay amplitudes, we show that the measured branching ratios imply large SU(3) breaking and large violations of the naive 1/N c counting. Furthermore, rescattering constrains the I = 0 amplitudes in the ππ and KK channels. Combining all this information, we show that, with present errors, the observed asymme- tries are marginally compatible with the Standard Model. Improving the experimental accuracy could lead to an indirect signal of new physics.
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Franco, E., Mishima, S. & Silvestrini, L. The Standard Model confronts CP violation in D 0 → π + π − and D 0 → K + K − . J. High Energ. Phys. 2012, 140 (2012). https://doi.org/10.1007/JHEP05(2012)140
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DOI: https://doi.org/10.1007/JHEP05(2012)140