584 research outputs found

    Final State Interactions and CP Violation in KLπ+πe+eK_L \to \pi^+ \pi^- e^+ e^-

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    Using chiral perturbation theory we calculate the imaginary parts of the KLπ+πe+eK_L \rightarrow \pi^+ \pi^- e^+ e^- form factors that arise from πππ+π\pi \pi \rightarrow \pi^+ \pi^- and πππ+πγ\pi \pi \rightarrow \pi^+ \pi^- \gamma^* rescattering. We discuss their influence on CP violating variables in KLπ+πe+eK_L \rightarrow \pi^+ \pi^- e^+ e^-.Comment: ; 12 pages, 2 figures, TeX format; uses epsf.tex, tables.tex, and phyzzx.te

    Long-lived neutral-kaon flux measurement for the KOTO experiment

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    The KOTO (K0K^0 at Tokai) experiment aims to observe the CP-violating rare decay KLπ0ννˉK_L \rightarrow \pi^0 \nu \bar{\nu} by using a long-lived neutral-kaon beam produced by the 30 GeV proton beam at the Japan Proton Accelerator Research Complex. The KLK_L flux is an essential parameter for the measurement of the branching fraction. Three KLK_L neutral decay modes, KL3π0K_L \rightarrow 3\pi^0, KL2π0K_L \rightarrow 2\pi^0, and KL2γK_L \rightarrow 2\gamma were used to measure the KLK_L flux in the beam line in the 2013 KOTO engineering run. A Monte Carlo simulation was used to estimate the detector acceptance for these decays. Agreement was found between the simulation model and the experimental data, and the remaining systematic uncertainty was estimated at the 1.4\% level. The KLK_L flux was measured as (4.183±0.017stat.±0.059sys.)×107(4.183 \pm 0.017_{\mathrm{stat.}} \pm 0.059_{\mathrm{sys.}}) \times 10^7 KLK_L per 2×10142\times 10^{14} protons on a 66-mm-long Au target.Comment: 27 pages, 16 figures. To be appeared in Progress of Theoretical and Experimental Physic

    Measurement of the Phase Difference Between eta00 and eta+- to a Precision of 1^0

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    We propose to add an additional regenerator to the E731 spectrometer in the MC beamline to enable us to measure the phase difference between the CP violation parameters {eta}{sub 00} and {eta}{sub +-} to an accuracy of 1{sup o}. Very general considerations indicate that CPT conservation requires the phase difference, {Delta}{phi} = Arg({eta}{sub 00}) - Arg({eta}{sub +-}), to be smaller than one degree. The current experimental value is {Delta}{phi} = (9.4 {+-} 5.1){sup o}

    Local structural alignment of RNA with affine gap model

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    Predicting new non-coding RNAs (ncRNAs) of a family can be done by aligning the potential candidate with a member of the family with known sequence and secondary structure. Existing tools either only consider the sequence similarity or cannot handle local alignment with gaps. In this paper, we consider the problem of finding the optimal local structural alignment between a query RNA sequence (with known secondary structure) and a target sequence (with unknown secondary structure) with the affine gap penalty model. We provide the algorithm to solve the problem. Based on a preliminary experiment, we show that there are ncRNA families in which considering local structural alignment with gap penalty model can identify real hits more effectively than using global alignment or local alignment without gap penalty model.The project is partially supported by the Seed Funding Programme for Basic Research (Project number: 200911159065) of the University of Hong Kong

    Importance of alkyl chain-length on the self-assembly of new Ni(qdt) 2 complexes and charge transport properties

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    A series of ionic complexes composed with ([Ni(qdt)2]2−) and alkyl substituted asymmetric viologen derivatives (AV+) as cations have been synthesized and characterized. A slight change in the length of the alkyl chain of AV+ alters the cation–anion packing and leads to different charge transport properties of these complexes. Here, we establish a structure–property relationship of Ni(qdt)2 complexes by structurally modifying the cations
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