We present measurements of the masses and decay widths of the baryonic states $Sigma_{c}(2455)^{0/++}$ and $Sigma_{c}(2520)^{0/++}$ using a data sample corresponding to an integrated luminosity of 711 fb$^{-1}$ collected with the Belle detector at th
e KEKB $e^{+}e^{-}$ asymmetric-energy collider operating at the $Upsilon(4S)$ resonance. We report the mass differences with respect to the $Lambda_{c}^{+}$ baryon $M(Sigma_{c}(2455)^{0})-M(Lambda_{c}^{+}) = 167.29pm0.01pm0.02$ MeV/$c^{2}$, $M(Sigma_{c}(2455)^{++})-M(Lambda_{c}^{+}) = 167.51pm0.01pm0.02$ MeV/$c^{2}$, $M(Sigma_{c}(2520)^{0})-M(Lambda_{c}^{+}) = 231.98pm0.11pm0.04$ MeV/$c^{2}$, $M(Sigma_{c}(2520)^{++})-M(Lambda_{c}^{+}) = 231.99pm0.10pm0.02$ MeV/$c^{2}$, and the decay widths $Gamma(Sigma_{c}(2455)^{0}) = 1.76pm0.04^{+0.09}_{-0.21}$ MeV/$c^{2}$, $Gamma(Sigma_{c}(2455)^{++}) = 1.84pm0.04^{+0.07}_{-0.20}$ MeV/$c^{2}$, $Gamma(Sigma_{c}(2520)^{0}) = 15.41pm0.41^{+0.20}_{-0.32}$ MeV/$c^{2}$, $Gamma(Sigma_{c}(2520)^{++}) = 14.77pm0.25^{+0.18}_{-0.30}$ MeV/$c^{2}$, where the first uncertainties are statistical and the second are systematic. The isospin mass splittings are measured to be $M(Sigma_{c}(2455)^{++})-M(Sigma_{c}(2455)^{0})=0.22pm0.01pm0.01$ MeV/$c^{2}$ and $M(Sigma_{c}(2520)^{++})-M(Sigma_{c}(2520)^{0})=0.01pm0.15pm0.03$ MeV/$c^{2}$. These results are the most precise to date.
We observe $D^0-bar{D}^0$ mixing in the decay $D^0rightarrow K^+pi^-$ using a data sample of integrated luminosity 976 fb$^{-1}$ collected with the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. We measure the mixing parameters ${x}^
2 = (0.09pm0.22)times 10^{-3}$ and $y = (4.6pm3.4)times 10^{-3}$ and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates $R_D = (3.53pm0.13)times 10^{-3}$, where the uncertainties are statistical and systematic combined. Our measurement excludes the no-mixing hypothesis at the 5.1 standard deviation level.
We search for CP violation in the decay $D^+rightarrow K^0_S K^+$ using a data sample with an integrated luminosity of 977 fb$^{-1}$ collected with the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. No CP violation has been observed
and the CP asymmetry in $D^+rightarrow K^0_S K^+$ decay is measured to be $(-0.25pm0.28pm0.14)%$, which is the most sensitive measurement to date. After subtracting CP violation due to $K^0-bar{K}^0$ mixing, the CP asymmetry in $D^+rightarrowbar{K}^0 K^+$ decay is found to be $(+0.08pm0.28pm0.14)%$.
We observe evidence for CP violation in the decay $D^+rightarrow K^0_Spi^+$ using a data sample with an integrated luminosity of 977 fb$^{-1}$ collected by the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. The CP asymmetry in the de
cay is measured to be $(-0.363pm0.094pm0.067)%$, which is 3.2 standard deviations away from zero, and is consistent with the expected CP violation due to the neutral kaon in the final state.
