853 research outputs found

    Kaon decay interferometry as meson dynamics probes

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    We discuss the time dependent interferences between KLK_L and KSK_S in the decays in 3π3\pi and ππγ\pi\pi\gamma, to be studied at interferometry machines such as the ϕ\phi-factory and LEAR. We emphasize the possibilities and the advantages of using interferences, in comparison with width measurements, to obtain information both on CPCP conserving and CPCP violating amplitudes. Comparison with present data and suggestions for future experiments are made.Comment: 15 pages, in RevTex, Report INFNNA-IV-93-31, UTS-DFT-93-2

    Non-Pauli Effects from Noncommutative Spacetimes

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    Noncommutative spacetimes lead to nonlocal quantum field theories (qft's) where spin-statistics theorems cannot be proved. For this reason, and also backed by detailed arguments, it has been suggested that they get corrected on such spacetimes leading to small violations of the Pauli principle. In a recent paper \cite{Pauli}, Pauli-forbidden transitions from spacetime noncommutativity were calculated and confronted with experiments. Here we give details of the computation missing from this paper. The latter was based on a spacetime Bχn\mathcal{B}_{\chi\vec{n}} different from the Moyal plane. We argue that it quantizes time in units of χ\chi. Energy is then conserved only mod 2πχ\frac{2\pi}{\chi}. Issues related to superselection rules raised by non-Pauli effects are also discussed in a preliminary manner.Comment: 15 Pages, 1 Table, Full details and further developments of arXiv:1003.2250. This version is close to the one accepted by JHE

    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

    Constraints on sdγs\to d \gamma from Radiative Hyperon and Kaon Decays

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    The quark-level process bsγb \to s \gamma has been used extensively to place constraints on new interactions. These same interactions can be further constrained from the enhancement they induce in the quark-level sdγs \to d \gamma transition, to the extent that the short distance contributions can be separated from the long distance contributions. We parameterize what is known about the long distance amplitudes and subtract it from the data in radiative hyperon and kaon decays to constrain new interactions.Comment: Latex 11 page

    Polarization in Hadronic \Lambda Hyperon Production and Chiral-Odd Twist-3 Distribution

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    Polarization of the \Lambda hyperon produced with a large transverse momentum in the unpolarized nucleon-nucleon collision is analyzed in the framework of QCD factorization. We focus on the mechanism in which the soft-gluon component of the chiral-odd spin-independent twist-3 quark distribution E_F(x,x) becomes a source of the polarized quark fragmenting into the polarized \Lambda. Our simple model estimate for this contribution indicates that it gives rise to a significant \Lambda polarization at large x_F. This is in parallel with the observation that the soft gluon pole mechanism gives rise to a large single transverse spin asymmetry in the pion production at x_F\to 1.Comment: 10 pages in LaTex + 5 figures in PS files. Phys. Rev. D in press. Title changed and some discussions adde

    Chiral Approach to Weak Radiative Hyperon Decays and the Ξ0>Λγ\Xi^0 --> \Lambda \gamma Asymmetry

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    We reanalyse the recent version of the chiral model of weak radiative hyperon decays, proposed by Borasoy and Holstein. It is shown that predictions of the analysed model are significantly changed when one accepts the usual classification of Λ(1405)\Lambda (1405) as an SU(3)-singlet. In particular, for the Ξ0Λγ\Xi ^0 \to \Lambda \gamma decay large negative asymmetry is obtained. This is contrasted with the Hara's-theorem-violating approaches where this asymmetry is large and positive.Comment: 15 LaTeX pages, 1 ps figur
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