نتایج جستجو برای: ππ interactions
تعداد نتایج: 389020 فیلتر نتایج به سال:
We present a measurement of the branching ratio of the CP violating decay KL→ ππ performed by the KLOE experiment at the φ factory DAΦNE. We use 328 pb of data collected in 2001 and 2002, corresponding to ∼ 150 million tagged KL mesons. We find BR(KL → ππ) = (1.963 ± 0.012stat. ± 0.017syst.) × 10. This branching ratio measurement is fully inclusive of final-state radiation. Using the above resu...
We perform a detailed Regge analysis of NN , πN and ππ scattering. From it, we find expressions that represent the ππ scattering amplitudes with an accuracy of a few percent, for exchange of isospin zero, and ∼ 15% for exchange of isospin 1, and this for energies s > 1.4GeV and for momentum transfers |t| < ∼ 0.4GeV. These Regge formulas are perfectly compatible with the low energy (s ∼ 1.4GeV) ...
We prove a general theorem about equal CP rate differences within pairs of U-spin related charmless B and Bs decays. Six pairs of decays into two pseudoscalar mesons are identified where such relations hold. Ratios of corresponding rate differences and certain ratios of rates measure U-spin breaking. These processes provide useful information on the weak phase γ = ArgV ∗ ub. Applications of U-s...
The phase variation of the σ → ππ amplitude is accurately determined as a function of mass from BES II data for J/Ψ → ωπ + π −. The determination arises from interference with the strong b 1 (1235)π amplitude. The observed phase variation agrees within errors with that in ππ elastic scattering. The σ pole appears as a conspicuous π + π − peak in BES II data for J/Ψ → ωπ + π − [1]. This peak is ...
The Schrödinger equation discribing the local potential model of a strong ππ-interaction was studied. The influence of the strong ππ-interaction of the behaviour of pionium nS-state wave functions at small distances is studied both analytically (perturbatively) and numerically. It is shown that in the whole the accounting of strong interaction results in multiplying pure Coulomb pionium wave fu...
The excited state lifetimes of DNA bases are often very short due to very efficient non-radiative processes assigned to the ππ*-nπ* coupling. A set of protonated aromatic diazine molecules (pyridazine, pyrimidine and pyrazine C4H5N2(+)) and protonated pyrimidine DNA bases (cytosine, uracil and thymine), as well as the protonated pyridine (C5H6N(+)), have been investigated. For all these molecul...
An elementary derivation is given of Cabibbo’s formula for subthreshold ππ charge-exchange (cx) interference in the three-meson final states produced in certain meson decays. The relative phase between the two interfering decay amplitudes from the ππ and ππ channels is found to depend almost entirely on the ClebschGordan coefficients appearing in the dominant isospin component of the final stat...
A new evaluation of the universal ππ scattering length relation is used to extract the ππ s-wave scattering lengths from threshold pion production data. Previous work has shown that the chiral perturbation series relating threshold pion production to ππ scattering lengths appears to converge well only for the isospin-2 case, giving a2 = −0.031±0.007m−1 π . A model-independent and data-insensiti...
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