Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session C9: Charm and Kaon Physics |
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Sponsoring Units: DPF Chair: Karen Gibson, University of Pittsburgh Room: Governor's Square 11 |
Saturday, May 2, 2009 1:30PM - 1:42PM |
C9.00001: Measurement of $D^0$-${\kern 0.2em\overline{\kern -0.2em D}}{}^0$ Mixing Using $D^0 \rightarrow K^+ \pi^- \pi^+ \pi^-$ Decays Ray F. Cowan We present preliminary results from a measurement of $D^0$- ${\kern 0.2em\overline{\kern -0.2em D}}{}^0$ mixing using the decays $D^0 \rightarrow K^+ \pi^- \pi^+ \pi^-$ in 480~fb${}^{-1} $ of data collected with the {\sl B{\scriptsize A}B{\scriptsize AR}} detector at the PEP-II $e^+e^-$ colliding-beam storage rings at SLAC. We report results for the mixing parameters ${x^ {\prime}}^2$, $y^{\prime}$, and the doubly Cabibbo-suppressed decay rate $R_D$. We present results with and without assuming CP conservation. [Preview Abstract] |
Saturday, May 2, 2009 1:42PM - 1:54PM |
C9.00002: Leptonic $D_S$ Decays Jonathon Coleman We present preliminary studies towards the measurement of the branching fraction of the $D_S$ meson to leptonic final states using data collected with the {\sl B{\scriptsize A}B {\scriptsize AR}} detector at the SLAC PEP-II asymmetric- energy $e^+e^-$ storage rings. This report will focus upon the final data set, covering the full range of leptonic decay modes. [Preview Abstract] |
Saturday, May 2, 2009 1:54PM - 2:06PM |
C9.00003: Search for $D^0$-${\kern 0.2em\overline{\kern -0.2em D}}{}^0$ mixing and CP violation Jordi Garra Tico Experimental results of charm mixing and CP violation searches in the {\sl B{\scriptsize A}B{\scriptsize AR}} experiment at the PEP-II $e^+e^-$ asymmetric-energy collider at SLAC will be presented. Though evidence of CP violation in the $D^0$ decay, mixing or interference has never been found, compelling evidence for mixing in the $D^0$ sector has been found in $D^0 \to K^+ \pi^-$ and $D^0 \to K^+ K^-$,$\pi^+\pi^-$ events. The talk will focus on time dependent analyses of two and three body $D$ meson decays, which provide the opportunity to measure the mixing parameters x and y directly. [Preview Abstract] |
Saturday, May 2, 2009 2:06PM - 2:18PM |
C9.00004: Measurement of the $D^0\to \phi \eta$, $D^0 \to \omega \eta$ and $D^0 \to K^* \eta$ Branching Fractions Katie Malone We present updates on the searches for three $D^0 \to V \eta$ decays, where the $D^0$ comes from the decay $D^{*+}\to D^0 \pi^+$ and $V$ is a $\phi$, $\omega$ or $K^*$ vector meson. These results use a 467~fb$^{-1}$ data sample collected with the {\sl B{\scriptsize A}B{\scriptsize AR}} detector at SLAC. [Preview Abstract] |
Saturday, May 2, 2009 2:18PM - 2:30PM |
C9.00005: Measurement of $CP$ Asymmetries in $D^0 \to h^+h^-$ Decays with the CDF Detector Angelo Di Canto The CDF experiment has now collected more than 4 fb$^{-1}$ of data and has access to the largest samples of $D^{*+}\to D^0 \pi^{+}$ decays currently available where $D^0$ decays as $D^0\rightarrow h^+h^-$ (with $h=K$ or $\pi$). Measurements of decay rates in these channels are sensitive to $CP$~violation and flavor mixing in the charm sector but require a careful analysis to separate signals from one another and from the background with the needed accuracy. We use a multivariate likelihood fit that combines kinematic and particle identification information to accurately determine the composition of the sample in terms of Cabibbo-favored, Cabibbo-suppressed and doubly-Cabibbo-suppressed decays. We apply this technique to a precision measurement of direct $CP$~violating asymmetries in $D^{0}\to \pi^{+}\pi^{-}$ and $D^{0}\to K^{+}K^{-}$ decays. [Preview Abstract] |
Saturday, May 2, 2009 2:30PM - 2:42PM |
C9.00006: Search for the Rare Decay $K_{L}\rightarrow\pi^{0}\pi^{0}\mu^{+}\mu^{-}$ David G. Phillips II Using data collected by the KTeV Experiment at Fermi National Accelerator Laboratory in Batavia, Illinois, this study will be the first experimental analysis of $K_{L}\rightarrow\pi^{0}\pi^{0}\mu^{+}\mu^{-}$. Although this decay mode is possible within the Standard Model, it is limited to a very narrow band of phase space. The HyperCP Experiment has recently observed three $\Sigma^{+}\rightarrow{\it p}\mu^{+}\mu^{-}$ events within a narrow dimuon mass range of 213.8 MeV/$c^{2}$ to 214.8 MeV/$c^{2}$. This suggests that the process could occur via a neutral intermediary particle, $\Sigma^{+}\rightarrow{\it p}X^{0}\rightarrow{\it p}\mu^{+}\mu^{-}$, with an $X^{0}$ mass of 214.3 MeV/$c^{2}$$\pm$0.5 MeV/$c^{2}$. Since the $X^{0}$ has a light mass and a low interaction probability, then it is most likely a new neutral boson that exists beyond the Standard Model. Recent theoretical predictions suggest that the decay mode $K_{L}\rightarrow\pi^{0}\pi^{0}\mu^{+}\mu^{-}$ can also occur via the aforementioned neutral boson: $K_{L}\rightarrow\pi^{0}\pi^{0}X^{0}\rightarrow\pi^{0}\pi^{0}\mu^{+}\mu^{-}$. Therefore, in addition to a Standard Model measurement, the search for $K_{L}\rightarrow\pi^{0}\pi^{0}\mu^{+}\mu^{-}$ is also carried out in an effort to address the viability of $X^{0}$ in explaining the HyperCP phenomena. [Preview Abstract] |
Saturday, May 2, 2009 2:42PM - 2:54PM |
C9.00007: Study of Semileptonic Decays $D \to K/\pi e^+ \nu_e$ at CLEO-c Bo Xin Using data collected at the $\psi(3770)$ resonance with the CLEO-c detector, we measure absolute branching fractions as a function of $q^2$, the invariant mass of the $e^+ \nu_e$ pair, for $D^0 \to K^- e^+ \nu_e$, $D^0 \to \pi^- e^+ \nu_e$, $D^+\to K_S^0 e^+ \nu_e $ and $D^+ \to \pi^0 e^+ \nu_e$. Our measurements of branching fractions, and most of our form factor measurements are the most precise to date. Using unquenched Lattice QCD calculations of the form factor magnitudes we extract the CKM matrix elements $|V_{\rm cs}|$ and $|V_{\rm cd}|$. Our measurement of $|V_{\rm cs}|$ is the most precise direct determination to date. [Preview Abstract] |
Saturday, May 2, 2009 2:54PM - 3:06PM |
C9.00008: Study of $D$ Meson Rare Semileptonic Decays at CLEO-c Junyan Ge Using data collected at the $\psi(3770)$ resonance with the CLEO-c detector at the Cornell Electron Storage Ring, we present results of a study of rare semileptonic decays of the $D$ mesons, including $D^0 \to \rho^- e^+ \nu_e$, $D^+ \to \rho^0 e^+ \nu_e$, $D^+ \to \omega e^+ \nu_e$, $D^+ \to \eta e^+ \nu_e$, $D^+ \to \eta^\prime e^+ \nu_e$, and $D^+ \to \phi e^+ \nu_e$. [Preview Abstract] |
Saturday, May 2, 2009 3:06PM - 3:18PM |
C9.00009: Radiative Decays of Charmonium David Besson We report studies of inclusive, and exclusive production of direct photons in charmonium decay. We find that the ratio of widths $\Gamma(\psi(2S) \to g g \gamma)/\Gamma(\psi(2S) \to ggg)$ is approximately half of the corresponding value for the $J/\psi$. We also report measurements of exclusive charmonium decays to $\eta\gamma$ and $\eta'\gamma$, and comment on the suppression of $\psi(2S)\to\eta\gamma$. [Preview Abstract] |
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