30,896 research outputs found
Pragmatic View of Short-Baseline Neutrino Oscillations
We present the results of global analyses of short-baseline neutrino
oscillation data in 3+1, 3+2 and 3+1+1 neutrino mixing schemes. We show that
the data do not allow us to abandon the simplest 3+1 scheme in favor of the
more complex 3+2 and 3+1+1 schemes. We present the allowed region in the 3+1
parameter space, which is located at between 0.82 and 2.19
at . The case of no oscillations is disfavored by about
, which decreases dramatically to about if the LSND data are
not considered. Hence, new high-precision experiments are needed to check the
LSND signal.Comment: 6 pages. Final version published in Phys. Rev. D 88, 073008 (2013
Short-Baseline Electron Neutrino Oscillation Length After Troitsk
We discuss the implications for short-baseline electron neutrino
disappearance in the 3+1 mixing scheme of the recent Troitsk bounds on the
mixing of a neutrino with mass between 2 and 100 eV. Considering the Troitsk
data in combination with the results of short-baseline nu_e and antinu_e
disappearance experiments, which include the reactor and Gallium anomalies, we
derive a 2 sigma allowed range for the effective neutrino squared-mass
difference between 0.85 and 43 eV^2. The upper bound implies that it is likely
that oscillations in distance and/or energy can be observed in radioactive
source experiments. It is also favorable for the ICARUS@CERN experiment, in
which it is likely that oscillations are not washed-out in the near detector.
We discuss also the implications for neutrinoless double-beta decay.Comment: 5 pages. Final version published in Phys.Rev. D87 (2013) 01300
基于弥散与分离裂缝模型的混凝土开裂比较研究
Crack propagation is one of the key issues for simulating nonlinear behavior and evaluating safety of concrete structures. The equivalent crack opening displacement of smeared damage-fracture model is formulated with damage parameter and crack band width. Mode I and mixed-mode fracture tests of concrete beams are analyzed using smeared and discrete crack models. The numerical results of smeared crack model, including load-carrying capacity, crack propagating depth and equivalent crack opening displacement, are consistent with those obtained using the discrete one. The comparative study shows that these two models have almost identical accuracy in evaluating both macro-scale and meso-scale structural information, but the smeared crack model has higher computation efficiency than the discrete one.裂缝扩展是影响混凝土结构非线性响应的重要因素,其扩展深度与张开位移是评价结构安全性的重要指标。基于弥散裂缝框架,该文建立了等效裂缝张开位移与损伤因子、断裂带宽度之间的函数关系。分别采用弥散、分离两类裂缝模型模拟I 型断裂和I-II混合型断裂试验,二者在结构承载力、裂缝扩展和裂缝张开位移方面均获得了基本一致的结果。数值算例表明弥散裂缝模型与分离裂缝模型计算精度接近但其效率更高。published_or_final_versio
Solving the Dirac equation with nonlocal potential by Imaginary Time Step method
The Imaginary Time Step (ITS) method is applied to solve the Dirac equation
with the nonlocal potential in coordinate space by the ITS evolution for the
corresponding Schr\"odinger-like equation for the upper component. It is
demonstrated that the ITS evolution can be equivalently performed for the
Schr\"odinger-like equation with or without localization. The latter algorithm
is recommended in the application for the reason of simplicity and efficiency.
The feasibility and reliability of this algorithm are also illustrated by
taking the nucleus O as an example, where the same results as the
shooting method for the Dirac equation with localized effective potentials are
obtained
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