1,628 research outputs found
Twist-3 contributions to processes in perturbative QCD approach
As one of the simplest hadronic processes, () could be a good testing ground for our understanding of
the perturbative and nonperturbative structure of QCD, and will be studied with
high precision at BELLE-\RNum{2} in the near future. In this paper, we revisit
these processes with twist-3 corrections in the perturbative QCD approach based
on the factorization theorem, in which transverse degrees of freedom as
well as resummation effects are taken into account. The influence of the
distribution amplitudes on the cross sections are discussed in detail. Our work
shows that not only the transverse momentum effects but also the twist-3
corrections play a significant role in the processes in the intermediate energy region. Especially in the few GeV
region, the twist-3 contributions become dominant in the cross sections. And it
is noteworthy that both the twist-3 result of the cross
section and that of the cross section agree well with the BELLE
and ALEPH measurements. For the pion and kaon angular distributions, there
still exist discrepancies between our results and the experimental
measurements. Possible reasons for these discrepancies are discussed briefly.Comment: 19 pages, 7 figures and 2 tables. Contents improved and more
discussions adde
Reinforced Mnemonic Reader for Machine Reading Comprehension
In this paper, we introduce the Reinforced Mnemonic Reader for machine
reading comprehension tasks, which enhances previous attentive readers in two
aspects. First, a reattention mechanism is proposed to refine current
attentions by directly accessing to past attentions that are temporally
memorized in a multi-round alignment architecture, so as to avoid the problems
of attention redundancy and attention deficiency. Second, a new optimization
approach, called dynamic-critical reinforcement learning, is introduced to
extend the standard supervised method. It always encourages to predict a more
acceptable answer so as to address the convergence suppression problem occurred
in traditional reinforcement learning algorithms. Extensive experiments on the
Stanford Question Answering Dataset (SQuAD) show that our model achieves
state-of-the-art results. Meanwhile, our model outperforms previous systems by
over 6% in terms of both Exact Match and F1 metrics on two adversarial SQuAD
datasets.Comment: Published in 27th International Joint Conference on Artificial
Intelligence (IJCAI), 201
The two-pseudoscalar-meson decay of with twist-3 corrections
The decays of are discussed
within the standard and modified hard scattering approach when including the
contributions from twist-3 distribution amplitudes and wave functions of the
light pseudoscalar meson. A model for twist-2 and twist-3 distribution
amplitudes and wave functions of the pion and kaon with BHL prescription are
proposed as the solution to the end-point singularities. The results show that
the contributions from twist-3 parts are actually not power suppressed
comparing with the leading-twist contribution. After including the effects from
the transverse momentum of light meson valence-quark state and Sudakov factors,
the decay widths of the into pions or kaons are comparable with the
their experimental data.Comment: 31 pages, 5 figures, 3 table
Induced-charge electroosmosis around conducting and Janus cylinder in microchip
The induced-charge elecetroosmosis around conducting/Janus cylinder with arbitrary Debye thickness is studied numerically, when an direct current weak electric filed is suddenly applied in a confined microchannel. It’s found that there are four large circulations around the conducting cylinder, and the total flux in the microchannel is zero; there are two smaller circulations around the Janus cylinder, and they are compressed to wall. A bulk flux, which has a parabolic relation with the applied electric field, is also predicted
Continuously improve the medical care quality and hospital management level through medical information system construction
The role of climatic variability in controlling carbon and water budgets in a boreal Scots pine forest during ten growing seasons
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