Bulletin of the American Physical Society
2006 APS April Meeting
Saturday–Tuesday, April 22–25, 2006; Dallas, TX
Session J10: Charm Mixing, Rare D and K Decays |
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Sponsoring Units: DPF Chair: Ian Shipsey, Purdue University Room: Hyatt Regency Dallas Cumberland C |
Sunday, April 23, 2006 1:15PM - 1:27PM |
J10.00001: Search for Charm Mixing with Flavor Tagged Dalitz Plots from $\psi(3770) \to D\bar D$ Eric White A quantum correlated ($C$=-1) $D\bar D$ state is produced from $\psi(3770) \to D\bar D$. Reconstructing one of the $D$ mesons as a $CP$ eigenstate, $y=\Delta \Gamma/2\Gamma$ can be determined by measuring the flavor specific branching ratios of the other meson. The flavor tag width is independent of the $CP$ quantum number however the branching ratio is inversely proportional to the total width. Consequently, charm threshold experiments have time-integrated sensitivity to $y$. Several multi-body $D^0$ decays proceed through intermediate states that are $CP$ eigenstates, such as $D^0 \to K^0_S f_0, f_0 \to \pi\pi$ and $D^0 \to \rho \pi^0, \rho \to \pi\pi$. The presence of mixing through $y$ would introduce an intensity modulation across the Dalitz plot (for flavor tagged $D$'s relative to the Dalitz plot observed in uncorrelated production) as a function of the $CP$ of the contributing amplitudes. We present a study of the sensitivity to $y$ with the anticipated CLEO-c data set. [Preview Abstract] |
Sunday, April 23, 2006 1:27PM - 1:39PM |
J10.00002: Measurement of the Strong Phase of $D^{0}\rightarrow K^{-}\pi^{+}$ Relative to $\bar{D^{0}}\rightarrow K^{-}\pi^{+}$ with CLEO-c Data Alexander Scott Quantum correlations in $\psi(3770) \rightarrow D^0 \bar{D^0}$ decays introduce sensitivity to charm mixing, doubly-Cabibbo-suppressed decay amplitudes, and strong phases into time-integrated $D^0$ and $\bar D^0$ decay rates. In this talk we describe the selection of CP-eigenstate $D^0$ and $\bar {D^0}$ tags in a sample of $\sim$300~pb$^{-1}$ of $e^+e^-$ annihilation data collected with the CLEO-c detector at the Cornell Electron Storage Ring. We use these tags and the quantum coherence of the $D^{0}\bar{D^{0}}$ pair to measure the rates for $D^{0}\rightarrow K^{-}\pi^{+}$ decays separately for CP-even and CP-odd states. We use the asymmetry between these rates to obtain a measurement of the relative strong phase $\delta$, which is an important ingredient for the interpretation of charm-mixing and CKM measurements at higher energies. Projections of the ultimate sensitivity for this determination with the full CLEO-c data sample are given. [Preview Abstract] |
Sunday, April 23, 2006 1:39PM - 1:51PM |
J10.00003: Determination of Charm-Mixing and Doubly-Cabibbo-Suppressed Decay Parameters with CLEO-c Data Adam Lincoln Information about charm mixing and doubly-Cabibbo-suppressed decays, as well as improved precision for measurement of the $D^0$-decay strong phase, can be obtained by combining multiple decay-rate measurements in $\psi(3770) \rightarrow D^0 \overline{D^0}$ events. We use a sample of $\sim 300$pb$^{-1}$ collected with the CLEO-c detector to measure the absolute branching fractions for semileptonic decays of $D^0$ mesons for which flavor and CP properties are inferred from an accompanying hadronic tag and the quantum coherence of the initial $D^{0}\overline {D^{0}}$ pair. We describe the fitting procedure for combining these and hadronic decay measurements, give results for current data, and project the ultimate sensitivity with the full CLEO-c sample for the relative strong phase $\delta$ and mixing amplitude $y$. [Preview Abstract] |
Sunday, April 23, 2006 1:51PM - 2:03PM |
J10.00004: Search for $D^0$ mixing in $D^0\rightarrow K^-\pi^+\pi^-\pi^+$ Yi Zheng We report on studies of the right sign and wrong sign decays of $D^0\rightarrow K^- \pi^+ \pi^- \pi^+$ using $230.4~{\rm fb}^{- 1}$ of data collected by the BaBar experiment. The preliminary measurement of the doubly Cabbibo-suppressed rate for the $D^0\rightarrow K^- \pi^+\pi^-\pi^+$ decay is presented, which can provide insights into searching for $D^0$ mixing via this hadronic decay of neutral $D$ meson. [Preview Abstract] |
Sunday, April 23, 2006 2:03PM - 2:15PM |
J10.00005: Flavor changing radiative $D$ meson decays Tim Klein Flavor changing radiative decays of the bottom quark provide tests of the Standard Model and powerful constraints on new physics. A better understanding of the long distance contributions to these processes may help reduce theoretical uncertainties on the predicted rates. Flavor changing radiative $D$~meson decays are dominated by long distance contributions due to a vector meson coupling to a photon and are suitable for confronting predictions of nonperturbative mechanisms. We present a measurement of the branching fraction of $D^{0} \rightarrow \phi \gamma$ in $281 \pb^{-1}$ of data collected by the CLEO-c detector at the Cornell Electron Storage Ring. We also present a measurement of the branching fraction, $D^{0} \rightarrow \phi \pi^{0}$, a significant background to the radiative decay. [Preview Abstract] |
Sunday, April 23, 2006 2:15PM - 2:27PM |
J10.00006: Search for Flavor-Changing Neutral-Current Charm Decays at BaBar Brian Petersen We present a search for flavor-changing neutral-current charm meson and baryon decays using data collected by the BaBar experiment. Flavor-changing neutral-current decays occur only through loop diagrams in the Standard Model and are therefore sensitive to certain types of new physics. The strongest constraints at present come from $K$ and $B$ decays, but charm decays are potentially also sensitive to new physics. The analysis will present a search for the decay modes $D^+\to\pi^+\ell^+\ell'^-$, $D_s^+\to K^+\ell^+\ell'^-$ and $\Lambda_c^+\to p\ell^+\ell'^-$. [Preview Abstract] |
Sunday, April 23, 2006 2:27PM - 2:39PM |
J10.00007: The Search for $K_{L} \rightarrow \pi^{0} \pi^{0} \gamma$ Dsvid Smith This talk describes a search for the rare decay $K_{L} \rightarrow \pi^{0} \pi^{0} \gamma$ conducted using data from the KTeV experiment. KTeV is a high-energy physics experiment that ran at Fermilab from 1997 to 1999, dedicated to searching for rare $K_{L}$ decays and to extracting CP violation parameters such as $\frac {\epsilon^{'}}{\epsilon}$. The decay $K_{L} \rightarrow \pi^{0} \pi^{0} \gamma$ is an electric quadrupole (E2) decay that is forbidden to fourth order in Chiral Perturbation Theory, and is interesting as a probe of the theory to the sixth order. Howver, the decay is experimentally hard to find due to a large background of $K_{L} \rightarrow 3\pi^{0}$ decays with one missing photon. The data sample used consisted of events with one of the internal photons converting to a Dalitz pair; this was done because of the sensitivity of the KTeV charged trigger. The primary background mode consisted of $K_{L} \rightarrow 3\pi^{0}$ events with one missing photon; a subsample of this mode, in which the missing photon was assumed to go down a calorimeter beam hole, was used as a normalization mode due to the similar topology and large number of events. Both the 1997 and 1999 KTeV data was used in a blind analysis to conduct the search for $K_{L} \rightarrow \pi^{0} \pi^{0} \gamma$ outlined in this talk. [Preview Abstract] |
Sunday, April 23, 2006 2:39PM - 2:51PM |
J10.00008: Latest KTeV results on the study of the decay $K_{L} \to \pi^{+}\pi^{-}\gamma $ Michael Ronquest This talk will present to date the most precise determination of the parameters that describe the M1 direct photon emission process in the decay $K_{L} \to \pi^{+}\pi^{-}\gamma $. The M1 process, along with the inner bremsstralung process, dominates this decay. This study was conducted using data collected during the 1997 run of the KTeV E832 experiment at Fermilab. A search for the CP violating E1 direct photon emission process will also be presented. [Preview Abstract] |
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