5,221 research outputs found
Branching ratios, asymmetries and polarizations of decays
We analyzed the nonleptonic decays with by employing the perturbative QCD (PQCD) factorization
approach. Here the branching ratios, the 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 decays are consistent
with the measured values within errors. As for decays, the branching ratios can reach the order of and could
be measured in the LHCb and Belle-II experiments. The numerical results show
that the direct asymmetries of the considered decays are very small. Thus
the observation of any large direct asymmetry for these decays will be a
signal for new physics. The mixing induced asymmetries in the neutral
modes are very close to , which suggests that these channels
can give a cross-check on the measurement of the Cabbibo-Kobayashi-Maskawa
(CKM) angle and . We found that the longitudinal polarization
fractions are suppressed to due to the large nonfactorizable
contributions. The magnitudes and phases of the two transverse amplitudes
and are roughly equal, which
is an indication for the approximate light quark helicity conservation in these
decays. The overall polarization observables of and
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
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 in the perturbative QCD approach
In this paper, we calculated the branching ratios of the quasi-two-body
decays
by employing the perturbative QCD (PQCD) approach. The contributions from the
-wave resonances , and were taken into
account. The two-pion distribution amplitude is
parameterized by the vector current time-like form factor 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
, while the two-body decay rates are extracted from those for the
corresponding quasi-two-body decays; (b) the whole pattern of the pion form
factor-squared measured by the BABAR Collaboration could be
understood based on our theoretical results; (c) the general expectation based
on the similarity between and
decays are confirmed: is consistent with the measured
within errors; and (d) new ratios
and 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 in the perturbative QCD approach
We study the quasi-two-body decays 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 -wave component in the time-like form factor
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
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 , 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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