65 research outputs found

    The relevance of inter-personal and interorganizational ties for interaction quality and outcomes of research collaborations in South Korea

    Get PDF
    Informal social ties have long been recognized as relevant not only for interaction between individuals, but also for knowledge transfer and other important outcomes of business activities. This applies in particular to East Asian countries such as South Korea where informal networks are widely believed to be prevalent in economy and society. However, less is known about their role in inter-organizational collaboration efforts, such as research collaborations. This research examines the relevance of inter-personal and inter-organizational ties for interaction quality and outcomes of research collaborations in South Korea. Two types of research collaborations are studied: new product development (NPD) collaborations between companies and university-industry research collaborations (UICs). Inter-personal ties are found in a majority of both types of collaborations being studied. However, whereas inter-organizational tie strength is strongly related to interaction quality and outcomes of research partnerships, inter-personal ties are not. Implications for research and for the management of inter-organizational research collaborations are shown

    An Inquiry into the Status and Nature of University-Industry Research Collaborations in Japan and Korea

    Get PDF
    University-industry collaboration (UIC) has become an increasingly frequent innovation strategy, especially in the Western hemisphere. But we know much less about such research collaborations in East Asia. This study explores and contrasts the current nature and status of UICs in Japan and Korea focusing on factors that facilitate the development and management of such research linkages. The findings indicate that UICs are path dependent, i.e. firms benefit from their experience with previous projects when collaborating with universities. At the same time, cultural factors appear to result in significant differences in the organization of UICs in Japan and Korea.University-industry collaboration, R&D collaboration, International comparison, Japan, Korea

    Nucleon Polarizibilities for Virtual Photons

    Get PDF
    We generalize the sum rules for the nucleon electric plus magnetic polarizability Σ=α+β\Sigma=\alpha+\beta and for the nucleon spin-polarizability γ\gamma, to virtual photons with Q2>0Q^2>0. The dominant low energy cross sections are represented in our calculation by one-pion-loop graphs of relativistic baryon chiral perturbation theory and the Δ(1232)\Delta(1232)-resonance excitation. For the proton we find good agreement of the calculated Σp(Q2)\Sigma_p(Q^2) with empirical values obtained from integrating up electroproduction data for Q2<0.4GeV2Q^2<0.4 GeV^2. The proton spin-polarizability γp(Q2)\gamma_p(Q^2) switches sign around Q2=0.4GeV2Q^2= 0.4 GeV^2 and it joins smoothly the "partonic" curve, extracted from polarized deep-inelastic scattering, around Q2=0.7GeV2Q^2=0.7 GeV^2. For the neutron our predictions of Σn(Q2)\Sigma_n(Q^2) and γn(Q2)\gamma_n(Q^2) agree reasonably well at Q2=0Q^2=0 with existing determinations. Upcoming (polarized) electroproduction experiments will be able to test the generalized polarizability sum rules investigated here.Comment: 12 pages, 5 figures, submittes to Nuclear Physics

    Pion-Nucleon Phase Shifts in Heavy Baryon Chiral Perturbation Theory

    Full text link
    We calculate the phase shifts in the pion-nucleon scattering using the heavy baryon formalism. We consider phase shifts for the pion energy range of 140 to 200200 MeV. We employ two different methods for calculating the phase shifts - the first using the full third order calculation of the pion-nucleon scattering amplitude and the second by including the resonances Δ\Delta and NN^* as explicit degrees of freedom in the Lagrangian. We compare the results of the two methods with phase shifts extracted from fits to the pion-nucleon scattering data. We find good to fair agreement between the calculations and the phase shifts from scattering data.Comment: 14 pages, Latex, 6figures. Revised version to appear in Phys.Rev.

    Dispersion relations in real and virtual Compton scattering

    Full text link
    A unified presentation is given on the use of dispersion relations in the real and virtual Compton scattering processes off the nucleon. The way in which dispersion relations for Compton scattering amplitudes establish connections between low energy nucleon structure quantities, such as polarizabilities or anomalous magnetic moments, and the nucleon excitation spectrum is reviewed. We discuss various sum rules for forward real and virtual Compton scattering, such as the Gerasimov-Drell-Hearn sum rule and its generalizations, the Burkhardt-Cottingham sum rule, as well as sum rules for forward nucleon polarizabilities, and review their experimental status. Subsequently, we address the general case of real Compton scattering (RCS). Various types of dispersion relations for RCS are presented as tools for extracting nucleon polarizabilities from the RCS data. The information on nucleon polarizabilities gained in this way is reviewed and the nucleon structure information encoded in these quantities is discussed. The dispersion relation formalism is then extended to virtual Compton scattering (VCS). The information on generalized nucleon polarizabilities extracted from recent VCS experiments is described, along with its interpretation in nucleon structure models. As a summary, the physics content of the existing data is discussed and some perspectives for future theoretical and experimental activities in this field are presented.Comment: 120 pages, 42 figures, to appear in Phys. Re

    Connecting the Quenched and Unquenched Worlds via the Large N_c World

    Get PDF
    In the large N_c(number of colors) limit, quenched QCD and QCD are identical. This implies that, in the effective field theory framework, some of the low energy constants in (N_c=3) quenched QCD and QCD are the same up to higher-order corrections in the 1/N_c expansion. Thus the calculation of the nonleptonic kaon decays relevant for the Delta I=1/2 rule in the quenched approximation is expected to differ from the unquenched one by an O(1/N_c) correction. However, the calculation relevant to the CP-violation parameter epsilon'/epsilon would have a relatively big higher-order correction due to the large cancellation in the leading order. Some important weak matrix elements are poorly known that even constraints with 100% errors are interesting. In those cases, quenched calculations will be very useful.Comment: 8 pages, one figure; minor typos correcte

    Parity Violation in gamma proton Compton Scattering

    Full text link
    A measurement of parity-violating spin-dependent gamma proton Compton scattering will provide a theoretically clean determination of the parity-violating pion-nucleon coupling constant hπNN(1)h_{\pi NN}^{(1)}. We calculate the leading parity-violating amplitude arising from one-loop pion graphs in chiral perturbation theory. An asymmetry of ~5 10^{-8} is estimated for Compton scattering of 100 MeV photons.Comment: 6 pages, 1 figure, latex. Reference adde

    Real and Virtual Compton Scattering off the Nucleon

    Get PDF
    A review is given of the very recent developments in the fields of real and virtual Compton scattering off the nucleon. Both real and virtual Compton scattering reactions are discussed at low outgoing photon energy where one accesses polarizabilities of the nucleon. The real Compton scattering at large momentum transfer is discussed which is asymptotically a tool to obtain information on the valence quark wave function of the nucleon. The rapid developments in deeply virtual Compton scattering and associated meson electroproduction reactions at high energy, high photon virtuality and small momentum transfer to the nucleon are discussed. A unified theoretical description of those processes has emerged over the last few years, which gives access to new, generalized parton distributions. The experimental status and perspectives in these fields are also discussed.Comment: 25 pages, 17 figure

    The Polarizability of the Deuteron

    Get PDF
    The scalar and tensor polarizabilities of the deuteron are calculated using the recently developed effective field theory that describes nucleon-nucleon interactions. Leading and next-to-leading order contributions in the perturbative expansion predict a scalar electric polarizability of 0.595 fm^3. The tensor electric polarizability receives contributions starting at next-to-leading order from the exchange of a single potential pion and is found to be -0.062 fm^3. We compute the leading contributions to the scalar and tensor magnetic polarizabilities, finding 0.067 fm^3 and 0.195 fm^3, respectively.Comment: 13 pages, 4 figures as 6 eps files, latex. References adde

    Radiative neutron beta-decay in effective field theory

    Get PDF
    We consider radiative \beta--decay of the neutron in heavy baryon chiral perturbation theory, with an extension including explicit \Delta degrees of freedom. We compute the photon energy spectrum as well as the photon polarization; both observables are dominated by the electron bremsstrahlung contribution. Nucleon-structure effects not encoded in the weak coupling constants g_A and g_V are determined at next-to-leading order in the chiral expansion, and enter at the {\cal O}(0.5%)-level, making a sensitive test of the Dirac structure of the weak currents possible.Comment: 11 pages, 4 eps figures, misprints fixed, to appear in Phys Lett
    corecore