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Register a new userMeasurement of the CKM angle $varphi_1$ in $B^0tobar{D}{}^{(*)0}h^0$, $bar{D}{}^0to K_S^0pi^+pi^-$ decays with time-dependent binned Dalitz plot analysis
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We report a measurement of the CP violation parameter $varphi_1$ obtained in a time-dependent analysis of $B^0tobar{D}{}^{(*)0}h^0$ decays followed by $bar{D}{}^0to K_S^0pi^+pi^-$ decay. A model-independent measurement is performed using the binned Dalitz plot technique. The measured value is $varphi_1 = 11.7^{circ}pm7.8^{circ}({rm stat.})pm 2.1^{circ}({rm syst.})$. Treating $sin{2varphi_1}$ and $cos{2varphi_1}$ as independent parameters, we obtain $sin{2varphi_1} = 0.43pm 0.27({rm stat.})pm 0.08({rm syst.})$ and $cos{2varphi_1} = 1.06pm 0.33({rm stat.})^{+0.21}_{-0.15}({rm syst.})$. The results are obtained with a full data sample of $772 times 10^6 Bbar{B}$ pairs collected near the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.
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We report a measurement of the amplitude ratio $r_S$ of $B^0 to D^0K^{*0}$ and $B^0 to bar{D^0}K^{*0}$ decays with a model-independent Dalitz plot analysis using $Dto K_S^0pi^+pi^-$ decays. Using the full data sample of $772times10^6$ $Bbar{B}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at KEKB accelerator the upper limit is $r_S < 0.87$ at the 68 % confidence level. This result is the first measurement of $r_S$ with a model-independent Dalitz analysis, and is consistent with results from other analyses. The value of $r_S$ indicates the sensitivity of the decay to $phi_3$ because the statistical uncertainty is proportional to $1/r_S$. The $r_S$ result is obtained from observables ($x_pm$, $y_pm$) begin{eqnarray} x_- &=& +0.4 ^{+1.0 +0.0}_{-0.6 -0.1} pm0.0 y_- &=& -0.6 ^{+0.8 +0.1}_{-1.0 -0.0} pm0.1 x_+ &=& +0.1 ^{+0.7 +0.0}_{-0.4 -0.1} pm0.1 y_+ &=& +0.3 ^{+0.5 +0.0}_{-0.8 -0.1} pm0.1 , end{eqnarray} where $x_pm = r_S cos(delta_S pm phi_3)$, $y_pm = r_S sin(delta_S pm phi_3)$ and $phi_3 (delta_S)$ are the weak (strong) phase difference between $B^0 to D^0K^{*0}$ and $B^0 to bar{D^0}K^{*0}$. The first uncertainty is statistical, the second is the experimental systematic and the third is the systematic due to the uncertainties on $c_i$ and $s_i$ parameters measured by CLEO.
The resonant substructures of $B^0 to overline{D}^0 pi^+pi^-$ decays are studied with the Dalitz plot technique. In this study a data sample corresponding to an integrated luminosity of 3.0 fb$^{-1}$ of $pp$ collisions collected by the LHCb detector is used. The branching fraction of the $B^0 to overline{D}^0 pi^+pi^-$ decay in the region $m(overline{D}^0pi^{pm})>2.1$ GeV$/c^2$ is measured to be $(8.46 pm 0.14 pm 0.29 pm 0.40) times 10^{-4}$, where the first uncertainty is statistical, the second is systematic and the last arises from the normalisation channel $B^0 to D^*(2010)^-pi^+$. The $pi^+pi^-$ S-wave components are modelled with the Isobar and K-matrix formalisms. Results of the Dalitz plot analyses using both models are presented. A resonant structure at $m(overline{D}^0pi^-) approx 2.8$ GeV$/c^{2}$ is confirmed and its spin-parity is determined for the first time as $J^P = 3^-$. The branching fraction, mass and width of this structure are determined together with those of the $D^*_0(2400)^-$ and $D^*_2(2460)^-$ resonances. The branching fractions of other $B^0 to overline{D}^0 h^0$ decay components with $h^0 to pi^+pi^-$ are also reported. Many of these branching fraction measurements are the most precise to date. The first observation of the decays $B^0 to overline{D}^0 f_0(500)$, $B^0 to overline{D}^0 f_0(980)$, $B^0 to overline{D}^0 rho(1450)$, $B^0 to D_3^*(2760)^- pi^+$ and the first evidence of $B^0 to overline{D}^0 f_0(2020)$ are presented.
The resonant substructure of $B_s^0 rightarrow bar{D}^0 K^- pi^+$ decays is studied with the Dalitz plot analysis technique. The study is based on a data sample corresponding to an integrated luminosity of $3.0,{rm fb}^{-1}$ of $pp$ collision data recorded by LHCb. A structure at $m(bar{D}^0 K^-) approx 2.86 {rm GeV}/c^2$ is found to be an admixture of spin-1 and spin-3 resonances. The masses and widths of these states and of the $D^*_{s2}(2573)^-$ meson are measured, as are the complex amplitudes and fit fractions for all the $bar{D}^0 K^-$ and $K^-pi^+$ components included in the amplitude model. In addition, the $D^*_{s2}(2573)^-$ resonance is confirmed to be spin-2.
We report a measurement of ${D^{0}}$-${overline{D}{}^{0}}$ mixing parameters and a search for indirect $CP$ violation through a time-dependent amplitude analysis of ${D^0to K_S^0pi^+pi^-}$ decays. The results are based on 921~fb$^{-1}$ of data accumulated with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Assuming $CP$ conservation, we measure the mixing parameters $x=(0.56pm0.19^{+0.03}_{-0.09}{^{+0.06}_{-0.09}})%$ and $y=(0.30pm0.15^{+0.04}_{-0.05}{^{+0.03}_{-0.06})}%$, where the errors are statistical, experimental systematic, and systematic due to the amplitude model, respectively. With $CP$ violation allowed, the parameters $|q/p|=0.90^{+0.16}_{-0.15}{^{+0.05}_{-0.04}}{^{+0.06}_{-0.05}}$ and $arg(q/p)=(-6pm11{pm3}{^{+3}_{-4}})^{circ}$ are found to be consistent with conservation of $CP$ symmetry in mixing and in the interference between mixing and decay, respectively.
We report measurements of $sin{2beta}$ and $cos{2beta}$ from a time-dependent Dalitz plot analysis of $B^{0} to D^{(*)} h^{0}$ with $D to K_{S}^{0} pi^{+} pi^{-}$ decays, where the light unflavored and neutral hadron $h^{0}$ is a $pi^{0}$, $eta$, or $omega$ meson. The analysis is performed with a combination of the final data sets of the babar and Belle experiments containing $471 times 10^{6}$ and $772 times 10^{6}$ $Bbar{B}$ pairs collected at the $Upsilonleft(4Sright)$ resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. We measure $sin{2beta} = 0.80 pm 0.14 ,(rm{stat.}) pm 0.06 ,(rm{syst.}) pm 0.03 ,(rm{model})$ and $cos{2beta} = 0.91 pm 0.22 ,(rm{stat.}) pm 0.09 ,(rm{syst.}) pm 0.07 ,(rm{model})$. The result for the direct measurement of the angle is $beta = left( 22.5 pm 4.4 ,(rm{stat.}) pm 1.2 ,(rm{syst.}) pm 0.6 ,(rm{model}) right)^{circ}$. The last quoted uncertainties are due to the composition of the $D^{0} to K_{S}^{0} pi^{+} pi^{-}$ decay amplitude model, which is newly established by a Dalitz plot amplitude analysis of a high-statistics $e^{+}e^{-} to cbar{c}$ data sample as part of this analysis. We find the first evidence for $cos2beta>0$ at the level of $3.7$ standard deviations. The measurement excludes the trigonometric multifold solution $pi/2 - beta = (68.1 pm 0.7)^{circ}$ at the level of $7.3$ standard deviations and therefore resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. The hypothesis of $beta = 0^{circ}$ is ruled out at the level of $5.1$ standard deviations, and thus CP violation is observed in $B^{0} to D^{(*)} h^{0}$ decays.
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