17,542 research outputs found
Weak Decays of Doubly Heavy Baryons: Multi-body Decay Channels
The newly-discovered decays into the , but the experimental data has indicated that this decay is not
saturated by any two-body intermediate state. In this work, we analyze the
multi-body weak decays of doubly heavy baryons , ,
, , and , in particular the
three-body nonleptonic decays and four-body semileptonic decays. We classify
various decay modes according to the quark-level transitions and present an
estimate of the typical branching fractions for a few golden decay channels.
Decay amplitudes are then parametrized in terms of a few SU(3) irreducible
amplitudes. With these amplitudes, we find a number of relations for decay
widths, which can be examined in future.Comment: 47pages, 1figure. arXiv admin note: substantial text overlap with
arXiv:1707.0657
A Deep Dive into Blockchain Selfish Mining
This paper studies a fundamental problem regarding the security of blockchain
on how the existence of multiple misbehaving pools influences the profitability
of selfish mining. Each selfish miner maintains a private chain and makes it
public opportunistically for the purpose of acquiring more rewards
incommensurate to his Hashrate. We establish a novel Markov chain model to
characterize all the state transitions of public and private chains. The
minimum requirement of Hashrate together with the minimum delay of being
profitable is derived in close-form. The former reduces to 21.48% with the
symmetric selfish miners, while their competition with asymmetric Hashrates
puts forward a higher requirement of the profitable threshold. The profitable
delay increases with the decrease of the Hashrate of selfish miners, making the
mining pools more cautious on performing selfish mining.Comment: 6 pages, 13 figure
The next-to-next-to-leading order soft function for top quark pair production
We present the first calculation of the next-to-next-to-leading order
threshold soft function for top quark pair production at hadron colliders, with
full velocity dependence of the massive top quarks. Our results are fully
analytic, and can be entirely written in terms of generalized polylogarithms.
The scale-dependence of our result coincides with the well-known two-loop
anomalous dimension matrix including the three-parton correlations, which at
the two-loop order only appear when more than one massive partons are involved
in the scattering process. In the boosted limit, our result exhibits the
expected factorization property of mass logarithms, which leads to a consistent
extraction of the soft fragmentation function. The next-to-next-to-leading
order soft function obtained in this paper is an important ingredient for
threshold resummation at the next-to-next-to-next-to-leading logarithmic
accuracy.Comment: 34 pages, 9 figures; v2: added references, matches the published
versio
CD-CNN: A Partially Supervised Cross-Domain Deep Learning Model for Urban Resident Recognition
Driven by the wave of urbanization in recent decades, the research topic
about migrant behavior analysis draws great attention from both academia and
the government. Nevertheless, subject to the cost of data collection and the
lack of modeling methods, most of existing studies use only questionnaire
surveys with sparse samples and non-individual level statistical data to
achieve coarse-grained studies of migrant behaviors. In this paper, a partially
supervised cross-domain deep learning model named CD-CNN is proposed for
migrant/native recognition using mobile phone signaling data as behavioral
features and questionnaire survey data as incomplete labels. Specifically,
CD-CNN features in decomposing the mobile data into location domain and
communication domain, and adopts a joint learning framework that combines two
convolutional neural networks with a feature balancing scheme. Moreover, CD-CNN
employs a three-step algorithm for training, in which the co-training step is
of great value to partially supervised cross-domain learning. Comparative
experiments on the city Wuxi demonstrate the high predictive power of CD-CNN.
Two interesting applications further highlight the ability of CD-CNN for
in-depth migrant behavioral analysis.Comment: 8 pages, 5 figures, conferenc
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