5,221 research outputs found

    Branching ratios, CPCP asymmetries and polarizations of Bψ(2S)VB\rightarrow \psi(2S) V decays

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    We analyzed the nonleptonic decays B/Bsψ(2S)VB/B_s\to \psi(2S) V with V=(ρ,ω,K,ϕ)V=(\rho, \omega, K^{*}, \phi) by employing the perturbative QCD (PQCD) factorization approach. Here the branching ratios, the CPCP asymmetries and the complete set of polarization observables are investigated systematically. Besides the traditional contributions from the factorizable and nonfactorizable diagrams at the leading order, the next-to-leading order (NLO) vertex corrections could also provide considerable contributions. The PQCD predictions for the branching ratios of the B(s)ψ(2S)K,ψ(2S)ϕB_{(s)}\to \psi(2S)K^{*}, \psi(2S) \phi decays are consistent with the measured values within errors. As for Bψ(2S)ρ,ψ(2S)ωB\to \psi(2S) \rho, \psi(2S) \omega decays, the branching ratios can reach the order of 10510^{-5} and could be measured in the LHCb and Belle-II experiments. The numerical results show that the direct CPCP asymmetries of the considered decays are very small. Thus the observation of any large direct CPCP asymmetry for these decays will be a signal for new physics. The mixing induced CPCP asymmetries in the neutral modes are very close to sin2β(s)\sin 2\beta_{(s)}, which suggests that these channels can give a cross-check on the measurement of the Cabbibo-Kobayashi-Maskawa (CKM) angle β\beta and βs\beta_s. We found that the longitudinal polarization fractions f0f_0 are suppressed to 50%\sim 50\% due to the large nonfactorizable contributions. The magnitudes and phases of the two transverse amplitudes A\mathcal {A}_{\parallel} and A\mathcal {A}_{\perp} are roughly equal, which is an indication for the approximate light quark helicity conservation in these decays. The overall polarization observables of Bψ(2S)K0B\to \psi(2S) K^{*0} and Bsψ(2S)ϕB_s\to \psi(2S) \phi channels are also in good agreement with the experimental measurements as reported by LHCb and BaBar. Other results can also be tested by the LHCb and Belle-II experiments.Comment: 14 pages, 1 figure, 6 table

    Logicality in Text Translation

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    Similarities and distinctions in logical structures of the Chinese and English languages are due to different but interrelated logical systems of China and the West. We may well say Logics influences translation and monitors the whole process of translation. In order to make translation more suitable to the target language’s logical system, this paper views from the aspect of logic and discusses some practical and feasible logical translation methods by analyzing examples. The paper puts forward some suggestions on logical text translation. 1) When translating texts showing the three universal laws of Logics, i.e. the law of identity, the law of non-contradiction and the law of excluded middle, and the law of space, translators should translate them according to the logical sequence of the source language. Chinese and English are different in leading inferential modes, therefore, translators should reorganize the logical sequence according to the phenomena that Chinese focus on “induction” and English focus on “deduction”. 2) When translating texts showing the law of time and the law of cause and effect, translators should also reorganize the logical sequence according to the target language’s features. Key words: logical law, text, Chinese translation, English translation Résumé: Les similarités et les différences dans les structures logiques des langues chinoise et anglaise sont dues aux systèmes logiques différents mais étroitement liés de la Chine et de l’Occident. On peut dire que la logique influence sur la traduction et dirige le processus entier de la traduction. Afin de rendre la traduction plus adaptable sur le système logique de la langue cible, cet essai discute, en analysant des exemples, des méthodes logiques de traduction pratiques et faisables. Il propose des suggestions sur la traduction logique du texte. 1) Quand la traduction présente les trois lois universelles de la logique : loi d’identité, loi de non-contradiction et loi de millieu exclut, loi d’espace, le traducteur doit traduire les textes suivant l’ordre logique de la langue source. Le chinois et l’anglais sont différents en ce qui concerne le mode d’inférence directeur. Ainsi, le traducteur doit réorganiser l’ordre logique selon le fait que le chinois insiste sur l’induction et l’anglais sur la déduction. 2) Quand la traduction présente la loi de temps et la loi de cause et effet, le traducteur doit réorganiser l’ordre logique d’après les caractère de la langue cible. Mots-Clés: loi logique, texte, traduction chinoise, traduction anglais

    Quasi-two-body decays Bηc(1S,2S)  [ρ(770),ρ(1450),ρ(1700)]  ππB \to \eta_c {(1S ,2S)}\;[\rho(770),\rho(1450),\rho(1700) \to ]\; \pi\pi in the perturbative QCD approach

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    In this paper, we calculated the branching ratios of the quasi-two-body decays Bηc(1S,2S)B \to \eta_c (1S ,2S) [ρ(770),ρ(1450),ρ(1700)]ππ[\rho(770), \rho(1450),\rho(1700)\to ] \pi\pi by employing the perturbative QCD (PQCD) approach. The contributions from the PP-wave resonances ρ(770)\rho(770), ρ(1450)\rho(1450) and ρ(1700)\rho(1700) were taken into account. The two-pion distribution amplitude ΦππP\Phi_{\pi\pi}^{\rm P} is parameterized by the vector current time-like form factor FπF_{\pi} to study the considered decay modes. We found that (a) the PQCD predictions for the branching ratios of the considered quasi-two-body decays are in the order of 10710610^{-7} \sim 10^{-6}, while the two-body decay rates B(Bηc(1S,2S)(ρ(1450),ρ(1700))){\cal B}(B \to \eta_c{(1S,2S)} (\rho(1450),\rho(1700))) are extracted from those for the corresponding quasi-two-body decays; (b) the whole pattern of the pion form factor-squared Fπ2|F_\pi|^2 measured by the BABAR Collaboration could be understood based on our theoretical results; (c) the general expectation based on the similarity between BηcππB \to \eta_c \pi\pi and BJ/ψππB \to J/\psi \pi\pi decays are confirmed: R2(ηc)0.45R_2(\eta_c)\approx 0.45 is consistent with the measured R2(J/ψ)0.56±0.09R_2(J/\psi)\approx 0.56\pm 0.09 within errors; and (d) new ratios R3(ηc(1S))R_3(\eta_c(1S)) and R4(ηc(2S))R_4(\eta_c(2S)) among the branching ratios of the considered decay modes are defined and could be tested by future experiments.Comment: 10 pages, 3 figure

    Quasi-two-body decays BDK(892)DKπB \to D K^*(892) \to D K \pi in the perturbative QCD approach

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    We study the quasi-two-body decays BDK(892)DKπB\to D K^*(892) \to D K\pi by employing the perturbative QCD approach. The two-meson distribution amplitudes \Phi_{K\pi}^{\text{P-wave}} are adopted to describe the final state interactions of the kaon-pion pair in the resonance region. The resonance line shape for the PP-wave KπK\pi component K(892)K^*(892) in the time-like form factor FKπ(s)F_{K\pi}(s) is parameterized by the relativistic Breit-Wigner function. For most considered decay modes, the theoretical predictions for their branching ratios are consistent with currently available experimental measurements within errors. We also disscuss some ratios of the branching fractions of the concerned decay processes. More precise data from LHCb and Belle-II are expected to test our predictions.Comment: 10 pages, 3 figures and 2 tables.To be published in EPJ

    The thermal evolution of nuclear matter at zero temperature and definite baryon number density in chiral perturbation theory

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    The thermal properties of cold dense nuclear matter are investigated with chiral perturbation theory. The evolution curves for the baryon number density, baryon number susceptibility, pressure and the equation of state are obtained. The chiral condensate is calculated and our result shows that when the baryon chemical potential goes beyond 1150MeV1150 \mathrm{MeV}, the absolute value of the quark condensate decreases rapidly, which indicates a tendency of chiral restoration.Comment: 17 pages, 9 figures, revtex
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