@misc{oai:niigata-u.repo.nii.ac.jp:00004704,
 author = {Shibata, Tatsunobu},
 month = {Sep},
 note = {B0 → Ksπ0 is b → s transition of penguin decay process, that is called flavor changing neutral current. The tree-level contribution is much smaller than penguin contribution. If the penguin deacay includes the intermadiate state of beyond Standard Model, for example SUSY particle, it is possible to search the new physics effect by comparing the sin2φ1 which is measured by B0 → J/ψKs decay mode. We measured indirect CP-asymmetry, effective sin2φ1 and direct CP-asymmetry by B0 → Ksπ0 decay with 253fb-1 data sample, corresponding to 275×106 BB pairs, accumulated from Jan. 2001 to Jun. 2004 at the KEKB factory. In this analysis, we used two new analysis methods. One is vertex reconsruction with only Ks particle and constrained by interaction point. We developed new vertex reconsruction method and modified vertex resolution for B0 → Ksπ0. Another is measurement of direct CP-asymmetry methos. In basically, we use proper time difference and flavor information, but we can do it from only flavor information. To reduce statistical error of direct CP-asymmetry parameter, we used events which does not have proper time difference information but has flavor information. We reconstructed B0 → Ksπ0 events and obtained 71 candidates, which have proper time difference and flavor information, and 176 candidates, which have only flavor information. We measured CP-asymmetry parameters by un-binned maximum likelihood fit. We got direct CP-asymmetry parameter as -0.11±0.20(stat)±0.09(syst), and indirect CP-asymmetry parameter as +0.32±0.61(stat)±0.13(syst). These results are consistent with Standard Model expectation within error. Since the statistic error are larger than systematic error, we need more statistics to conclude that CP-Violation of B0 → Ksπ0 resides within or beyond the Standard Model expectation., 新大博（理）乙第53号, 新大博（理）乙第53号},
 title = {Study of CP‐Violating Asymmetries in B0 ￫ Ks π0　Decay},
 year = {2005}
}