English

$D^0$-$\bar{D}^0$ mixing and CP violation results from Belle

High Energy Physics - Experiment 2014-11-11 v1

Abstract

We report the results on D0D^0-Dˉ0\bar{D}^0 mixing in the decays of D0K+πD^0\to K^+\pi^- and D0KS0π+πD^0\to K_S^0\pi^+\pi^-, and CP violation in D0π0π0D^0\to\pi^0\pi^0 using a data sample with an integrated luminosity of about 1~ab1^{-1} recorded with the Belle detector, at different center of mass energies. The mixing is observed in D0K+πD^0\to K^+\pi^- with the mixing parameters x2=(0.09±0.22)×103x'^2=(0.09\pm 0.22)\times 10^{-3}, y=(4.6±3.4)×103y'=(4.6\pm 3.4)\times 10^{-3} and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates RD=(3.53±0.13)×103R_{D}=(3.53\pm0.13)\times 10^{-3}, where the quoted uncertainties combine both statistical and systematic contributions. For the D0KS0π+πD^0\to K_S^0\pi^+\pi^- decay, assuming CP conservation we measure mixing parameters x=(0.56±0.190.090.09+0.03+0.06)%x=(0.56\pm 0.19^{+0.03+0.06}_{-0.09-0.09})\% and y=(0.30±0.150.050.06+0.04+0.03)%y=(0.30\pm 0.15^{+0.04+0.03}_{-0.05-0.06})\%, where the uncertainties are statistical, experimental systematics, and that due to amplitude model. We measure the mixing parameters allowing CP violation for this decay mode, and obtain q/p=0.900.150.040.05+0.16+0.05+0.06|q/p|=0.90^{+0.16+0.05+0.06}_{-0.15-0.04-0.05} and arg(q/pq/p)=(6±11±34+3)(-6\pm 11 \pm3^{+3}_{-4})^{\circ} that are consistent with no CP violation. The time-integrated CP asymmetry in the decay D0π0π0D^0\to\pi^0\pi^0 is measured to be, [0.03±0.64(stat)±0.10(syst)]%[-0.03\pm 0.64(stat) \pm 0.10(syst)]\%, consistent with CP conservation. We also present an updated measurement of CP asymmetry in D0KS0π0D^0\to K_S^0\pi^0.

Keywords

Cite

@article{arxiv.1411.2083,
  title  = {$D^0$-$\bar{D}^0$ mixing and CP violation results from Belle},
  author = {N. K. Nisar},
  journal= {arXiv preprint arXiv:1411.2083},
  year   = {2014}
}