2,530 research outputs found
Determination of pion distribution amplitudes from the electromagnetic form factor with the data-driven dispersion relation
We study the pion electromagnetic form factor in the modulus squared
dispersion relation, and do the model independent extraction of the most
important nonperturbative parameters in pion light-cone distribution amplitude.
The motivation of this work is the recent measurement of timelike form factor
in the resonant regions, which makes up the piece lacking solid QCD-based
calculation. With the perturbative QCD calculation up to next-to-leading-order
QCD corrections and twist four level of meson distribution amplitudes, we
obtain the chiral mass of pion meson as . More accuracy measurement of the timelike
form factor are desirable to help us to determine the lowest gegenbauer moments
in pion distribution amplitudes with the data-driven dispersion relation method
developed in this work.Comment: 9pages, 6 figures, 1 tabl
Low-cycle fatigue life prediction of a polycrystalline nickel-base superalloy using crystal plasticity modelling approach
Charmless two-body meson decays in perturbative QCD factorization approach
The perturbative QCD (PQCD) approach based on factorization has made a
great achievement for the QCD calculation of the hadronic B decays. Regulating
the endpoint divergence by the transverse momentum of quarks in the
propagators, one can do the perturbation calculation for kinds of diagrams
including the annihilation type diagrams. In this paper, we review the current
status of PQCD factorization calculation of two-body charmless decays up to the next-to-leading order (NLO) QCD corrections. two new power
suppressed terms in decaying amplitudes are also taken into account. By using
the universal input (non-perturbative) parameters, we collected the branching
ratios and asymmetry parameters for all the charmless two body
decays, calculated in the PQCD approach up to the NLO, including some power
suppressed terms in decaying amplitudes. The results are compared with the ones
from QCD factorization approach, soft-collinear effective theory approach and
the current experimental measurements. For most considered B meson decays, the
PQCD results for branching ratios agree well with other approaches and the
experimental data. The PQCD predictions for the asymmetry parameters
for many of the decay channels do not agree with other approaches, but have a
better agreement with the experimental data. The longstanding puzzle
about the pattern of the direct CP asymmetries of the penguin-dominated decays can be understood after the inclusion of the NLO contributions
in PQCD. The NLO corrections and power suppressed terms play an important role
in the color suppressed and pure annihilation type decay modes. These rare
decays are more sensitive to different types of corrections, providing
opportunity to examine the factorization approach with the more precise
experimental measurements.Comment: 51 pages, 4 figures, 11 tables, references added, typos remove
Temporal Action Localization with Enhanced Instant Discriminability
Temporal action detection (TAD) aims to detect all action boundaries and
their corresponding categories in an untrimmed video. The unclear boundaries of
actions in videos often result in imprecise predictions of action boundaries by
existing methods. To resolve this issue, we propose a one-stage framework named
TriDet. First, we propose a Trident-head to model the action boundary via an
estimated relative probability distribution around the boundary. Then, we
analyze the rank-loss problem (i.e. instant discriminability deterioration) in
transformer-based methods and propose an efficient scalable-granularity
perception (SGP) layer to mitigate this issue. To further push the limit of
instant discriminability in the video backbone, we leverage the strong
representation capability of pretrained large models and investigate their
performance on TAD. Last, considering the adequate spatial-temporal context for
classification, we design a decoupled feature pyramid network with separate
feature pyramids to incorporate rich spatial context from the large model for
localization. Experimental results demonstrate the robustness of TriDet and its
state-of-the-art performance on multiple TAD datasets, including hierarchical
(multilabel) TAD datasets.Comment: An extended version of the CVPR paper arXiv:2303.07347, submitted to
IJC
Clinicopathological and prognostic significance of mTOR and phosphorylated mTOR expression in patients with esophageal squamous cell carcinoma: a systematic review and meta-analysis
Modeling and implementing of an automated warehouse via colored timed Petri nets
The automated warehouse considered here consists of a number of rack locations with three cranes, a narrow aisle shuttle, and several buffer stations with the roller. Based on analyzing of the behaviors of the active resources in the system, a modular and computerized model is presented via a colored timed Petri net approach, in which places are multicolored to simplify model and characterize control flow of the resources, and token colors are defined as the routes of storage/retrieval operations. In addition, an approach for realization of model via visual c++ is briefly given. These facts allow us to render an emulate system to simulate a discrete control application for on-line monitoring, dynamic dispatching control and off-line revising scheduler policies
Solitary hepatic lymphangioma: a one-case report
Hepatic lymphangiomas, malformations of the liver lymphatic system, are extremely rare conditions in adults. A 41-year-old man presented with right upper abdominal pain for 6Â months was introduced in this report. Ultrasound (US) and computed tomography (CT) scan demonstrated a giant cystictumor with a pedunculatedextrahepatic growth pattern. Due to diagnostic uncertainty, a partial hepatectomy was performed and pathological results confirmed the diagnosis of solitary hepatic lymphangioma. In this article, we reviewed the clinical and pathology features, preoperative diagnostic challenges, and treatments of hepaticlymphangiomas
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