# Time-dependent amplitude analysis of B0 --> K0S pi+ pi-

Abstract : We perform a time-dependent amplitude analysis of $B^0 \to K^0_S\pi^+\pi^-$ decays to extract the CP violation parameters of $f_0(980) K^0_S$ and $\rho^0(770) K^0_S$ and the direct CP asymmetry of $K^{*+}(892) \pi^-$. The results are obtained from a data sample of $(383 \pm 3) \times 10^6$ $B\bar{B}$ decays, collected with the BABAR detector at the PEP-II asymmetric-energy $B$ factory at SLAC. We find two solutions, with an equivalent goodness-of-fit. Including systematic and Dalitz plot model uncertainties, the combined confidence interval for values of the CP parameter $\beta_{eff}$ in $B^0$ decays to $f_0(980) K^0_S$ is $18^o < \beta_{eff} < 76^o$ at 95% confidence level (C.L). CP conservation in $B^0$ decays to $f_0(980) K^0_S$ is excluded at $3.5\sigma$ including systematic uncertainties. For $B^0$ decays to $\rho^0(770) K^0_S$, the combined confidence interval is $-9^o < \beta_{eff} < 57^o$ at 95% C.L. In decays to $K^{*+}(892) \pi^-$ we measure the direct CP asymmetry to be $A_{CP}=-0.20 \pm 0.10 \pm 0.01 \pm 0.02$. The measured phase difference (including $B^0\bar{B}^0$ mixing) between decay amplitudes of $B^0 \to K^{*+}(892) \pi^-$ and $\bar{B}^0 \to K^{*-}(892) \pi^+$, excludes the interval $-137^o < \Delta\Phi(K^{*+}(892) \pi^-) < -5^o$ at 95% C.L.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00419181
Contributor : Claudine Bombar <>
Submitted on : Tuesday, September 22, 2009 - 4:57:57 PM
Last modification on : Tuesday, December 22, 2020 - 12:40:02 PM

### Citation

B. Aubert, Y. Karyotakis, J.P. Lees, V. Poireau, E. Prencipe, et al.. Time-dependent amplitude analysis of B0 --> K0S pi+ pi-. Physical Review D, American Physical Society, 2009, 80, pp.112001. ⟨10.1103/PhysRevD.80.112001⟩. ⟨in2p3-00419181⟩

Record views