Is national border weakening in technology space? Analysis of inter-urban hierarchy with Chinese patent licensing data

The literature on the diffusion of innovation from the 1970s has found that a domestic interregional hierarchy was the most common conduit for the innovation diffusion. Has this hierarchy become obsolete in today’s globalized economy? As less-developed cities within a developing country absorb technological innovation directly from overseas, is the nationality of cities becoming less important? Contemporary economic geography literature tends to answer these questions in the affirmative. This study challenges that resounding yes. From our analysis of Chinese patent licensing data, we find evidence not only for the survival but also for the reinforcement of the domestic inter-urban hierarchy. While it is true that the number of cities licensing patents to import technology from overseas has been increasing, it is being outmatched by the domestic patent licensing of the top-tier cities within China. This development demonstrates that the role of the nation as a spatial unit of knowledge production and application has remained constant throughout, even as the technological level of its cities has improved under the increasing globalization of the national economy

Singlet Fermionic Dark Matter with Dark ZZ

We present a fermionic dark matter model mediated by the hidden gauge boson. We assume the QED-like hidden sector which consists of a Dirac fermion and U(1)$_X$ gauge symmetry, and introduce an additional scalar electroweak doublet field with the U(1)$_X$ charge as a mediator. The hidden U(1)$_X$ symmetry is spontaneously broken by the electroweak symmetry breaking and there exists a massive extra neutral gauge boson in this model which is the mediator between the hidden and visible sectors. Due to the U(1)$_X$ charge, the additional scalar doublet does not couple to the Standard Model fermions, which leads to the Higgs sector of type I two Higgs doublet model. The new gauge boson couples to the Standard Model fermions with couplings proportional to those of the ordinary $Z$ boson but very suppressed, thus we call it the dark $Z$ boson. We study the phenomenology of the dark $Z$ boson and the Higgs sector, and show the hidden fermion can be the dark matter candidate.Comment: 10 pages, 3 figure

Constraints on the dark Z model from the Higgs boson phenomenology

We study constraints on the hidden sector model mediated by an additional SU(2) Higgs doublet from the phenomenology of Higgs bosons. The hidden sector is assumed to contain a hidden U(1) gauge symmetry and the hidden U(1) gauge boson gets the mass by the electroweak symmetry breaking to be a dark Z boson. The Higgs sector of the model is similar to that of the two Higgs doublet model of type I except for the absence of the CP-odd scalar boson. Using the programs of HiggsBounds and HiggsSignals, we incorporate current experimental limits from LEP, Tevatron and LHC to examine the Higgs sector in our model and derive constraints on model parameters. We also discuss the implications of the model on the dark matter phenomenology.Comment: 18 pages, 7 figure