No Arabic abstract
We present the results of a Dalitz plot analysis of D^0 to K^0_S pi^0 pi^0 using the CLEO-c data set of 818 inverse pico-barns of e^+ e^- collisions accumulated at sqrt{s} = 3.77 GeV. This corresponds to three million D^0 D^0-bar pairs from which we select 1,259 tagged candidates with a background of 7.5 +- 0.9 percent. Several models have been explored, all of which include the K^*(892), K^*_2(1430), K^*(1680), the f_0(980), and the sigma(500). We find that the combined pi^0 pi^0 S-wave contribution to our preferred fit is (28.9 +- 6.3 +- 3.1)% of the total decay rate while D^0 to K^*(892)^0 pi^0 contributes (65.6 +- 5.3 +- 2.5)%. Using three tag modes and correcting for quantum correlations we measure the D^0 to K^0_S pi^0 pi^0 branching fraction to be (1.059 +- 0.038 +- 0.061)%.
We perform an analysis of the $D^+ to K^0_S pi^+ pi^0$ Dalitz plot using a data set of 2.92 fb$^{-1}$ of $e^+e^-$ collisions at the $psi(3770)$ mass accumulated by the BESIII Experiment, in which 166694 candidate events are selected with a background of 15.1%. The Dalitz plot is found to be well-represented by a combination of six quasi-two-body decay channels ($K^0_Srho^+$, $K^0_Srho(1450)^+$, $overline{K}^{*0}pi^+$, $overline{K}_0(1430)^0pi^+$, $overline{K}(1680)^0pi^+$, $overline{kappa}^0pi^+$) plus a small non-resonant component. Using the fit fractions from this analysis, partial branching ratios are updated with higher precision than previous measurements.
Using a data sample corresponding to 13.7 fb^-1 collected with the CLEO II and II.V detectors, we report new branching fraction measurements for two Cabibbo-suppressed decay modes of the D^+ meson: Br(D^+ to pi^+ pi^0) = (1.3 +/- 0.2) x 10^-3 and Br(D^+ to bar{K}^0 K^+) = (5.2 +/- 0.6) x 10^-3 which are significant improvements over past measurements. The errors include statistical and systematical uncertainties as well as the uncertainty in the absolute D^+ branching fraction scale. We also set the first 90% confidence level upper limit on the branching fraction of the doubly Cabibbo-suppressed decay mode Br(D^+ to K^+ pi^0) < 4.2 x 10^-4.
Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay $D^0 to bar{K}^0pi^-mu^+ u$. Using a model that includes a $bar{K}^0 pi^-$ S-wave component, we measure the form factor ratios to be r_v= 1.706+-0.677+-0.342 and r_2= 0.912+-0.370+-0.104 and the S-wave amplitude to be A=0.347+-0.222+-0.053 GeV^-1. Finally, we measure the vector semileptonic branching ratio $frac{Gamma(D^0 to K^{*}(892){-}mu^+ u)}{Gamma(D^0 to bar{K}^0pi^-pi^+)}= 0.337+-0.034+-0.013.
Based on an $e^{+}e^{-}$ collision data sample corresponding to an integrated luminosity of 2.93 $mathrm{fb}^{-1}$ collected with the BESIII detector at $sqrt{s}=3.773 mathrm{GeV}$, the first amplitude analysis of the singly Cabibbo-suppressed decay $D^{+}to K^+ K_S^0 pi^0$ is performed. From the amplitude analysis, the $K^*(892)^+ K_S^0$ component is found to be dominant with a fraction of $(57.1pm2.6pm4.2)%$, where the first uncertainty is statistical and the second systematic. In combination with the absolute branching fraction $mathcal{B}(D^+to K^+ K_S^0 pi^0)$ measured by BESIII, we obtain $mathcal{B}(D^+to K^*(892)^+ K_S^0)=(8.69pm0.40pm0.64pm0.51)times10^{-3}$, where the third uncertainty is due to the branching fraction $mathcal{B}(D^+to K^+ K_S^0 pi^0)$. The precision of this result is significantly improved compared to the previous measurement.
We present an observation and rate measurement of the decay D0 -> K+pi-pi0 produced in 9/fb of e+e- collisions near the Upsilon(4S) resonance. The signal is inconsistent with an upward fluctuation of the background by 4.9 standard deviations. We measured the rate of D0 -> K+pi-pi0 normalized to the rate of D0bar -> K+pi-pi0 to be 0.0043 +0.0011 -0.0010 (stat) +/- 0.0007 (syst). This decay can be produced by doubly-Cabibbo-suppressed decays or by the D0 evolving into a D0bar through mixing, followed by a Cabibbo-favored decay to K+pi-pi0. We also found the CP asymmetry A=(8 +25 -22)% to be consistent with zero.