Time-Dependent Amplitude Analysis of B^0->Kspi+pi- decays with the BaBar Experiment and constraints on the CKM matrix using the B->K*pi and B->rho K modes

Abstract : A time-dependent amplitude analysis of $B^0 \to K^0_S\pi^+\pi^-$ decays is performed to extract the CP violation parameters of $f_0(980)K_S^0$ and $\rho^0(770)K_S^0$, and direct CP asymmetries of $K^*(892)^\pm\pi^\mp$. The results are obtained from a data sample of $(383\pm 3)\times10^{6}$ $B\bar{B}$ decays, collected with the \babar\ detector at the PEP-II asymmetric-energy B factory at SLAC. Two solutions are found, with equivalent goodness-of-fit merits. Including systematic and Dalitz plot model uncertainties, the combined confidence interval for values of $\beta_{\rm eff}$ in $B^0$ decays to $f_0(980)K_S^0$ is $18^\circ< \beta_{\rm eff}<76^\circ$ (at $95\%$ C.L.); CP conservation in $B^0$ decays to $f_0(980)K_S^0$ is excluded at $3.5\sigma$, including systematics. For $B^0$ decays to $\rho^0(770)K_S^0$, the combined confidence interval is $-9^\circ< \beta_{\rm eff}<57^\circ$ (at $95\%$ C.L.). In decays to $K^*(892)^\pm\pi^\mp$ the measured direct CP asymmetry parameter is $A_{\rm CP}=-0.20 \pm 0.10\pm 0.01\pm 0.02$. The measured phase difference between the decay amplitudes of $B^0\to K^*(892)^+\pi^-$ and $\bar{B}^0\to K^*(892)^-\pi^+$ excludes the $[-132^\circ : +25^\circ]$ interval (at $95\%$ C.L.). Branching fractions and CP asymmetries are measured for all significant intermediate resonant modes. The measurements on $\rho^0(770) K^0_S$ and $K^{*\pm}(892)\pi^{\mp}$ are used as inputs to a phenomenological analysis of $B \to K^*\pi$ and $B \to \rho K$ decays based solely on $SU(2)$ isospin symmetry. Adding external information on the CKM matrix, constraints on the hadronic parameter space are set. For $B \to K^*\pi$, the preferred intervals for color-allowed electroweak penguins are marginally compatible with theoretical expectations. The constraints on CKM parameters are dominated by theoretical uncertainties. A prospective study, based on the expected increase in precision from measurements at LHCb, and at future programs such as Super-B or Belle-upgrade, illustrates the physics potential of this approach.
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High Energy Physics - Experiment. Université Paris-Diderot - Paris VII, 2008. English


https://tel.archives-ouvertes.fr/tel-00379188
Contributor : Luis Alejandro Pérez Pérez <>
Submitted on : Monday, April 27, 2009 - 7:09:00 PM
Last modification on : Tuesday, April 28, 2009 - 8:26:07 AM

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Luis Alejandro Pérez Pérez. Time-Dependent Amplitude Analysis of B^0->Kspi+pi- decays with the BaBar Experiment and constraints on the CKM matrix using the B->K*pi and B->rho K modes. High Energy Physics - Experiment. Université Paris-Diderot - Paris VII, 2008. English. <tel-00379188>

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