$\phi {}^{{{\mathit K}_S^0} {{\mathit \pi}} {{\mathit \pi}}}$
INSPIRE search
Parametrizes $\mathit CP$ violation in the interference between ${{\mathit D}^{0}}$ mixing and decay. The mass eigenstates ${{\mathit D}_{{{1}}}^{0}}$ and ${{\mathit D}_{{{2}}}^{0}}$ are related to the $\mathit C$ = $\pm1$ states by $|{{\mathit D}_{{{1,2}}}}>$ = p$~|{{\mathit D}^{0}}>$ + q $|{{\overline{\mathit D}}^{0}}>$. In the absence of $\mathit CP$ violation in the decay, and using the usual phase convention where $\mathit CP$ conservation implies q/p is real, $\phi {}^{{{\mathit K}_S^0} {{\mathit \pi}} {{\mathit \pi}}}$ is identical to the decay-mode-independent parameter $\phi $ = arg(q/p).