Does China's Trade Expansion Help African Development? - A South-South Trade Model Approach

With the aim to explain the explosive growth of trade between China and Africa, especially the impacts of China's exportation on African countries, a simple South-South trade model is constructed to formulate the idea that for a technologically backward country to improve its production capability, when there exists nontrivial substitution effects, it is better to import from a South country which has superior technology, than from a North country with enormous technological advance. Then the Comtrade panel data are used to assess the impacts of imports from China (in comparison with those from the USA and France) on Sub-Saharan African manufactured exports (as proxies of their production performances). The results confirm the inference drawn from the model.South-South trade;impact of Chinese exportation on Africa;technology spillover effects;intermediate goods;substitution effects.

A γγ\gamma\gamma Collider for the 750 GeV Resonant State

Recent data collected by ATLAS and CMS at 13 TeV collision energy of the LHC indicate the existence of a new resonant state $\phi$ with a mass of 750 GeV decaying into two photons $\gamma\gamma$. The properties of $\phi$ should be studied further at the LHC and also future colliders. Since only $\phi \to \gamma\gamma$ decay channel has been measured, one of the best ways to extract more information about $\phi$ is to use a $\gamma\gamma$ collider to produce $\phi$ at the resonant energy. In this work we show how a $\gamma\gamma$ collider helps to verify the existence of $\phi$ and to provide some of the most important information about the properties of $\phi$, such as branching fractions of $\phi\to V_1V_2$. Here $V_i$ can be $\gamma$, $Z$, or $W^\pm$. We also show that by studying angular distributions of the final $\gamma$'s in $\gamma\gamma \to \phi \to \gamma\gamma$, one can obtain crucial information about whether this state is a spin-0 or a spin-2 state.Comment: ReTex, 12 page with 6 figures. Expanded discussion on distinguishing spin-0 and spin-2 cases. Several figures adde

Zc(3900)/Zc(3885)Z_c(3900)/Z_c(3885) as a virtual state from πJ/ψ−Dˉ∗D\pi J/\psi-\bar{D}^*D interaction

In this work, we study the $J/\psi\pi$ and $\bar{D}^*D$ invariant mass spectra of the $Y(4260)$ decay to find out the origin of the $Z_c(3900)$ and $Z_c(3885)$ structures. The $J/\psi \pi-\bar{D}^{*}D$ interaction is studied in a coupled-channel quasipotential Bethe-Saltpeter equation approach, and embedded to the $Y(4260)$ decay process to reproduce both $J/\psi\pi^-$ and $D^{*-}D^0$ invariant mass spectra observed at BESIII simultaneously. It is found out that a virtual state at energy about 3870 MeV is produced from the interaction when both invariant mass spectra are comparable with the experiment. The results support that both $Z_c(3900)$ and $Z_c(3885)$ have the same origin, that is, a virtual state from $J/\psi \pi-\bar{D}^*{D}$ interaction, in which the $\bar{D}^*{D}$ interaction is more important and the coupling between $\bar{D}^*{D}$ and $J/\psi\pi$ channels plays a minor role.Comment: 8 pages, 4 figures, more reference adde

Interpretation of Y(4390)Y(4390) as an isoscalar partner of Z(4430)Z(4430) from D∗(2010)Dˉ1(2420)D^*(2010)\bar{D}_1(2420) interaction

Invoked by the recent observation of $Y(4390)$ at BESIII, which is about 40 MeV below the $D^*(2010)\bar{D}_1(2420)$ threshold, we investigate possible bound and resonance states from the $D^*(2010)\bar{D}_1(2420)$ interaction with the one-boson-exchange model in a quasipotential Bethe-Salpeter equation approach. A bound state with quantum number $0^-(1^{--})$ is produced at 4384 MeV from the $D^ (2010)\bar{D}_1(2420)$ interaction, which can be related to experimentally observed $Y(4390)$. Another state with quantum number $1^+(1^{+})$ is also produced at $4461+i39$ MeV from this interaction. Different from the $0^-(1^{--})$ state, the $1^+(1^{+})$ state is a resonance state above the $D^*(2010)\bar{D}_1(2420)$ threshold. This resonance state can be related to the first observed charged charmonium-like state $Z(4430)$, which has a mass about 4475 MeV measured above the threshold as observed at Belle and LHCb. Our result suggests that $Y(4390)$ is an isoscalar partner of the $Z(4430)$ as a hadronic-molecular state from the $D^*(2010)\bar{D}_1(2420)$ interaction.Comment: 5 pages, 1 figur

Estimating Chinese Interprovincial OutPut Spillovers with Provincial Input-Output Tables

This paper aims at estimating productivity improvement of Chinese 17 relatively backward provinces in manufactures through importing manufactured intermediates from advanced provinces on the basis of just published 2002 national and provincial input-output tables. As Chinese regional inequality remains large, North-South spillover models of trade are appropriate to guide this study. Applying reliable methods to approximate net interprovincial imports by province and sector and the allocation of imported manufactured inputs among sectors within each province, we use a Cob-Douglas production function incorporating Dixit-Stiglitz type increasing returns to variety to deal with the manufactured inputs, and treat the output spillovers as one part of total factor productivity. According to our estimations, as expected, interprovincial imports of manufactured inputs have significant impacts on industrial sectors as well on all sectors of these provinces.Chinese interprovincial trade;North-South spillovers;input-output tables;regional inequality;imported intermediates