By analyzing $e^+e^-$ annihilation data with an integrated luminosity of $2.93~\rm fb^{ -1}$ collected at the center-of-mass energy $\sqrt s=$ 3.773 GeV with the BESIII detector, we present the first absolute measurements of the branching fractions of twenty Cabibbo-suppressed hadronic $D^{ 0(+)}$ decays involving multiple pions. The largest four branching fractions obtained are $\mathcal{ B}(D^0\to\pi^+\pi^-\pi^0)= (1.343\pm0.013_{ \rm stat}\pm0.016_{ \rm syst})\%$, $\mathcal{ B}(D^0\to\pi^+\pi^-2\pi^0)= (0.998\pm0.019_{ \rm stat}\pm0.024_{ \rm syst})\%$, $\mathcal{ B}(D^+\to 2\pi^+\pi^-\pi^0)= (1.174\pm0.021_{ \rm stat}\pm0.021_{ \rm syst})\%$, and $\mathcal{ B}(D^+\to 2\pi^+\pi^-2\pi^0)=(1.074\pm0.040_{ \rm stat}\pm0.030_{ \rm syst})\%$. The $CP$ asymmetries for the six decays with highest event yields are also determined.
Categories: hep-ex