Bulletin of the American Physical Society
2005 APS April Meeting
Saturday–Tuesday, April 16–19, 2005; Tampa, FL
Session X7: Particle Decays I |
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Sponsoring Units: DPF Chair: Alan Schwartz, University of Cincinnati Room: Marriott Tampa Waterside Room 1 |
Tuesday, April 19, 2005 10:45AM - 11:09AM |
X7.00001: KTeV Results on CP violation in $K_L \to \pi^+ \pi^- e^+ e^-$ Alexander Golossanov The decay $K_L \to \pi^+ \pi^- e^+ e^-$~ offers an excellent opportunity to measure indirect CP violation in the kaon system. This process exhibits a large CP violating asymmetry through a T-odd angular variable, and allows access to the charge structure of neutral kaon and possible CP-violating $E1$ amplitude through precision measurement of the decay form factors. The KTeV experiment at Fermilab has identified over 5000 of these rare decays. We report the final measurements of the asymmetry, form factors, branching ratio and the $K^0$~ charge radius based on this data sample. [Preview Abstract] |
Tuesday, April 19, 2005 11:09AM - 11:21AM |
X7.00002: Measurement of the Decay Rate and Form Factor Parameters of the Decay $K_L\to e^+e^-\gamma$ Michael Wilking We present a measurement of the branching ratio, BR($K_L\to e^+e^-\gamma$), using data from the 1997 run of the KTeV (E799) experiment at Fermilab. We also report a measurement of the $K_L\to\gamma^\ast\gamma$ form factor using the parametrizations by Bergstr\"{o}m Mass\'{o} Singer (BMS) and by D'Ambrosio Isidori Portol\'{e}s (DIP). Our result is a factor of 13 improvement in statistics over the previous most precise result. [Preview Abstract] |
Tuesday, April 19, 2005 11:21AM - 11:33AM |
X7.00003: New Results on the search for rare decays {\mbox{$K^+ \! \rightarrow \! \pi^+ \gamma$}} and {\mbox{$K^+ \! \rightarrow \! \pi^+ \gamma \gamma$}} from BNL E949 Benji Lewis Experiment E949 is designed to search for the rare kaon decay {\mbox{$K^+ \! \rightarrow \! \pi^+ \nu \overline{\nu}$}}; however, many other $K^+$ decay modes can be studied with this detector. Results from two of these modes, {\mbox{$K^+ \! \rightarrow \! \pi^+ \gamma$}} and {\mbox{$K^+ \! \rightarrow \! \pi^+ \gamma \gamma$}} will be presented. The former decay mode violates angular momentum conservation. An improved upper limit on the branching ratio will be shown. The latter decay mode is of interest as a test of Chiral Perturbation Theory, and in particular of unitarity corrections. [Preview Abstract] |
Tuesday, April 19, 2005 11:33AM - 11:45AM |
X7.00004: Progress on rare K and $\pi$ decays from BNL E949 Ilektra A. Christidi The E949 experiment at BNL's AGS has improved upon the already high $\pi^{o}$ detection efficiency of the previous E787 experiment by as much as an order of magnitude. This enhanced photon detection efficiency enables significant improvements in background rejection and sensitivity for the decays $\pi^{o} \rightarrow \nu \overline{\nu}$ and $K^{+} \rightarrow \pi^{+} \nu \overline{\nu}$ in the kinematic region of $p_{\pi^{+}}<195MeV/c$ (``PNN2''). New results and progress in these modes will be presented. The helicity suppressed $\pi^{o} \rightarrow \nu \overline{\nu}$ decay gives information on neutrino mass, new weakly interacting particles and cosmological models. The experimental method and analysis strategy for the detection of this decay will be described, as well as the impact of the new results on the SM and beyond. This measurement is done as a byproduct of the primary mode of E949: $K^{+} \rightarrow \pi^{+} \nu \overline{\nu}$. Progress on the search for this mode in the kinematic region of $p_{\pi^{+}}<195MeV/c$ (``PNN2'') will also be presented. [Preview Abstract] |
Tuesday, April 19, 2005 11:45AM - 11:57AM |
X7.00005: Measurement of the $\Lambda_c$ Mass Brian Petersen We present a precision measurement of the mass of the $\Lambda_c^+$ baryon using data collected by the BaBar experiment. To keep the systematic uncertainty as low as possible, the measurement is done using the low Q-value decay, $\Lambda_c^+ \to \Lambda^0 K_S^0 K^+$. The measurement requires a thorough understanding of the tracking performance and energy loss corrections which is demonstrated using several control samples. [Preview Abstract] |
Tuesday, April 19, 2005 11:57AM - 12:09PM |
X7.00006: Search for the 7-prong tau decay Ruben Ter-Antonyan A long standing puzzle in $\tau$ lepton decays is the apparent suppression of decays with seven or more hadrons in the final state. We present results on the search for the $\tau$ decay into seven charged pions with and without a $\pi^{0}$, and a neutrino. Our data sample, a total of 232.2 fb$^{-1}$ on and near the $\Upsilon(4S)$-resonance, was collected using the BaBar detector at the PEP-II asymmetric $e^+e^-$-collider at the Stanford Linear Accelerator Center. The results from this analysis are a significant improvement over the previously established upper limit on the decay branching ratio. [Preview Abstract] |
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