Measurement of D0-D0bar mixing in D0->Ks pi+ pi- decays

We report a measurement of D0-D0bar mixing in D0->Ks pi+ pi- decays using a time-dependent Dalitz plot analysis. We first assume CP conservation and subsequently allow for CP violation. The results are based on 540 fb$^{-1}$ of data accumulated with the Belle detector at the KEKB $e^+e^-$ collider. Assuming negligible CP violation, we measure the mixing parameters $x=(0.80\pm0.29^{+0.09 +0.10}_{-0.07 -0.14})$ and $y=(0.33\pm0.24^{+0.08 +0.06}_{-0.12 -0.08})$, where the errors are statistical, experimental systematic, and systematic due to the Dalitz decay model, respectively. Allowing for CP violation, we obtain the $CPV$ parameters $|q/p|=0.86^{+0.30 +0.06}_{-0.29 -0.03}\pm0.08$ and $\arg(q/p)=(-14^{+16 +5 +2}_{-18 -3 -4})^\circ$.