A General Analysis of Wtb anomalous Couplings

We investigate new physics effects on the Wtb effective couplings in a model-independent manner. The new physics effects are summarized as four independent couplings $f_1^L$, $f_1^R$, $f_2^L$ and $f_2^R$. Using single-top-quark productions and W-helicity fraction measurements at the LHC and Tevatron, we perform a global fit to impose constraints on top quark effective couplings. We introduce a set of parameters $x_0$, $x_m$, $x_p$ and $x_5$ to study the correlations among Wtb effective couplings. We show that (i) improving the measurements of $\sigma_t$ and $\sigma_{tW}$ is important in constraining the correlation of $(f_1^R,f_2^R)$ and $(f_2^L,f_2^R)$; (ii) $f_1^L$ and $f_2^R$ are anti-correlated, which is sensitive to all the experiments; (iii) $f_1^R$ and $f_2^L$ are also anti-correlated, which is sensitive to the W-helicity measurements; (iv) the correlation between $f_2^L$ and $f_2^R$ is sensitive to the precision of $\sigma_t$, $\sigma_{tW}$ and $F_0$ measurements. The effective Wtb couplings are studied in three kinds of new physics models: $SU(2)_1 \times SU(2)_2 \times U(1)_X$ models, vector-like quark models and Littlest Higgs model with and without T-parity. The Wtb couplings in the left-right model and the un-unified model are sensitive to the ratio of gauge couplings when the new heavy gauge boson's mass ($M_{W'}$) is less than several hundred GeV, but the constraint is loose if $M_{W'}>1$ TeV. The Wtb couplings in vector-like quark models and the Littlest Higgs models are sensitive to the mixing angles of new heavy particles and SM particles. We also include the constraints of the oblique T-parameter and Zbb couplings which impose much tighter constraints on the mixing angles. We show that the Wtb coupling constraints become relevant if the precision of single top production cross section measurements could be reduced to 1\% relative to the SM predictions in future.Comment: Chin. Phys. C in pres

Kondo regime of the impurity spectral function and the current noise spectrum in the double impurity Anderson model

The dissipaton equations of motion (DEOM) method is one of the most popular methods for simulating quantum impurity systems. In this article, we use DOEM theory to deal with the Kondo problem of the double quantum dots (DQDs) impurity system. We focus on the impurity spectral function and the total noise spectral function, this two function will be used to describe the Kondo effect of this system. The influence of the interaction, the hooping and the difference of the chemical potential between the two dots on the Kondo effect of the system is studied. We find that the interaction between the two dots can influence the Kondo effect of the system a lot

Classifying Relations via Long Short Term Memory Networks along Shortest Dependency Path

Relation classification is an important research arena in the field of natural language processing (NLP). In this paper, we present SDP-LSTM, a novel neural network to classify the relation of two entities in a sentence. Our neural architecture leverages the shortest dependency path (SDP) between two entities; multichannel recurrent neural networks, with long short term memory (LSTM) units, pick up heterogeneous information along the SDP. Our proposed model has several distinct features: (1) The shortest dependency paths retain most relevant information (to relation classification), while eliminating irrelevant words in the sentence. (2) The multichannel LSTM networks allow effective information integration from heterogeneous sources over the dependency paths. (3) A customized dropout strategy regularizes the neural network to alleviate overfitting. We test our model on the SemEval 2010 relation classification task, and achieve an $F_1$-score of 83.7\%, higher than competing methods in the literature.Comment: EMNLP '1

Optimal Distributed Controller Design for Nonlinear Coupled Dynamical Networks

This paper is concerned with the optimal distributed impulsive controller design for globally exponential synchronization of nonlinear dynamical networks with coupling delay. By the Lyapunov-Razumikhin method, a novel criterion is proposed to guarantee the global exponential synchronization of the coupled delayed network with distributed impulsive control in terms of matrix inequalities. The sum of coupling strengths of the distributed impulsive control is minimized to save the control effort. Finally, the effectiveness of the proposed method has been demonstrated by some simulations