2,783 research outputs found
Partial wave analysis of decays with arbitrary spins
In this paper, we propose a method to construct the decay amplitudes in the
orbital () and spin () coupling scheme for particles with arbitrary
spins. For the decay with only massive particles involved, the angular
dependence is completely encoded in the angular momentum part, and the spins of
daughter particles are coupled in the rest frame of the mother particle, which
contributes only a constant factor. For the sequential decay, the total
amplitude is constructed by the two amplitudes evaluated in the rest
frame of their own mother particles, and then they are transformed to the
common frame, usually chosen as the laboratory frame, by certain Lorentz
transformations. In this way, it is easy to add the amplitudes of possible
different decay chains coherently. If massless particles show up in the final
states, the polarizations are expressed in helicity basis and the amplitudes
are modified correspondingly.Comment: 12 pages, 0 figure
A Residual Fully Convolutional Network (Res-FCN) for Electromagnetic Inversion of High Contrast Scatterers at an Arbitrary Frequency Within a Wide Frequency Band
Many successful machine learning methods have been developed for
electromagnetic inverse scattering problems. However, so far, their inversion
has been performed only at the specifically trained frequencies. To make the
machine-learning-based inversion method more generalizable for realistic
engineering applications, this work proposes a residual fully convolutional
network (Res-FCN) to perform EM inversion of high contrast scatterers at an
arbitrary frequency within a wide frequency band. The proposed Res-FCN combines
the advantages of the Res-Net and the fully convolutional network (FCN).
Res-FCN consists of an encoder and a decoder: the encoder is employed to
extract high-dimensional features from the measured scattered field through the
residual frameworks, while the decoder is employed to map from the
high-dimensional features extracted by the encoder to the electrical parameter
distribution in the inversion region by the up-sample layer and the residual
frameworks. Four numerical examples verify that the proposed Res-FCN can
achieve good performance in the 2-D EM inversion problem for high contrast
scatterers with anti-noise ability at an arbitrary frequency point within a
wide frequency band
- …