The semileptonic baryonic decay Ds+→ppˉe+νeD_s^+\to p\bar p e^+ \nu_e

The decay $D_s^+\to p \bar p e^+\nu_e$ with a proton-antiproton pair in the final state is unique in the sense that it is the only semileptonic baryonic decay which is physically allowed in the charmed meson sector. Its measurement will test our basic knowledge on semileptonic $D_s^+$ decays and the low-energy $p\bar p$ interactions. Taking into account the major intermediate state contributions from $\eta, \eta', f_0(980)$ and $X(1835)$, we find that its branching fraction is at the level of $10^{-9} \sim 10^{-8}$. The location and the nature of $X(1835)$ state are crucial for the precise determination of the branching fraction. We wish to trigger a new round of a careful study with the upcoming more data in BESIII as well as the future super tau-charm factory.Comment: final version, accepted for publication in Phys. Lett.

Branching fractions of semileptonic DD and DsD_s decays from the covariant light-front quark model

Based on the predictions of the relevant form factors from the covariant light-front quark model, we show the branching fractions for the $D (D_s) \to (P,\,S,\,V,\,A)\,\ell\nu_\ell$ ($\ell=e$ or $\mu$) decays, where $P$ denotes the pseudoscalar meson, $S$ the scalar meson with a mass above 1 GeV, $V$ the vector meson and $A$ the axial-vector one. Comparison with the available experimental results are made, and we find an excellent agreement. The predictions for other decay modes can be tested in a charm factory, e.g., the BESIII detector. The future measurements will definitely further enrich our knowledge on the hadronic transition form factor as well as the inner structure of the even-parity mesons ($S$ and $A$).Comment: Predictions on D-> K1(1270), K1(1400) l nu rates correcte

A Descriptive Model of Robot Team and the Dynamic Evolution of Robot Team Cooperation

At present, the research on robot team cooperation is still in qualitative analysis phase and lacks the description model that can quantitatively describe the dynamical evolution of team cooperative relationships with constantly changeable task demand in Multi-robot field. First this paper whole and static describes organization model HWROM of robot team, then uses Markov course and Bayesian theorem for reference, dynamical describes the team cooperative relationships building. Finally from cooperative entity layer, ability layer and relative layer we research team formation and cooperative mechanism, and discuss how to optimize relative action sets during the evolution. The dynamic evolution model of robot team and cooperative relationships between robot teams proposed and described in this paper can not only generalize the robot team as a whole, but also depict the dynamic evolving process quantitatively. Users can also make the prediction of the cooperative relationship and the action of the robot team encountering new demands based on this model. Journal web page & a lot of robotic related papers www.ars-journal.co

Dynamic response of underground box-type structure to explosion seismic waves

The dynamic response of lined tunnels with a uniform box-type cross-section buried into elastic half-space to explosion seismic waves is studied by employing the matrix force method and treating the structure as a connecting rod system interacting with foundation. The main equations for dynamic analyzing of the hyperstatic structure are deduced and solving method is proposed. A case study is implemented to investigate the influence of span-height ratio of the structure and foundation-structure wave impedance ratio. The results are presented in nondimensional form to obtain a clear physical understanding of the dynamic response of structure. It is shown that the dynamic response of box-type structure can be significantly influenced by the span-height ratio as well as the foundation conditions. Since nondimensional parameters are adopted, the results are independent of dimension and can extend to structures with different size and working conditions. This study provides an analysis method and new insights into the dynamic response of underground box-type structures

Contagion in a Financial System

Financial contagion is often observed in recent financial crisis, which illustrates a critical need for new and fundamental understanding of its dynamics. So in this paper we mainly focus on modeling and analysing the financial contagion in a system where a large number of financial institutions are randomly connected by the direct balance sheets linkages own to the lending or borrowing relationships. We propose a simple contagion algorithm to study the effect of several determinants, such as the topology of financial network, exposure ratio, leverage ratio, and the liquidation ratio. One of our finding is that the financial contagion is weaker as the growth of connectivity of network, so a financial system with a higher connectivity is more stability or robustness; we also find that the exposure ratio increases the risk of financial contagion, but both the leverage ratio and liquidation ratio has a negative relationship on financial contagion