New physics in singly Cabibbo-suppressed D decays

Understand

A U-spin relation among four ratios of amplitudes for $D^0 \to \pi^+K^-$, $K^+\pi^-$, $K^+K^-, \pi^+\pi^-$, including first, second and third order U-spin breaking, has been derived recently with a precision of $10^{-3}$.

• We study effects of new $|\Delta C|=1$ operators on this relation.
• We find that it is not affected by U-spin scalar operators, including QCD penguin and chromomagnetic dipole operators occurring in supersymmetric and extra-dimensional models.
• The relation is modified by new $U=1$ operators with a sensitivity of a few percent characteristic of second order U-spin breaking.