Speaker
Isabella Garzia
(INFN)
Description
We report the measurement of the asymmetry $A_{CP}$ of the branching fractions of $D^0\rightarrow K^-\pi^+$ in the CP-odd and CP-even eigenstates using a data sample of $2.92$ fb$^{-1}$ collected with the BESIII detector at the center-of-mass energy $\sqrt{s}=3.773$ GeV.
With the measured $A_{CP}$ the strong phase difference $\delta_{K\pi}$ between the doubly Cabibbo-suppressed process $\bar{D}^0\rightarrow K^-\pi^+$ and the Cabibbo-favored process $D^0\rightarrow K^-\pi^+$ is extracted.
Using world-average values of external parameters, we obtain the most precise measurement of $\delta_{K\pi}$ to date: $\cos\delta_{K\pi}=1.02\pm0.11\pm0.06\pm0.01$.
The first and second uncertainties are statistical and systematic, respectively, while the third arises from external input.
Based on the same data sample a preliminary results of the parameter $y_{CP}$ in $D^0-\bar{D}^0$ oscillation is obtained.
Finally, a summary of the recent results from charmonium spectroscopy is reported.
The high statistics accumulated at the $Y(4260)$ and $Y(4360)$ energies help us to understand the nature and the proprieties of the XYZ states.
Author
Isabella Garzia
(INFN)
