Differences between European Regional Innovation Systems in Terms of Technological and Economic Characteristics

innovation, networks

Charged lepton mixing and oscillations from neutrino mixing in the early Universe

Charged lepton mixing as a consequence of neutrino mixing is studied for two generations $e,\mu$ in the temperature regime $m_\mu \ll T \ll M_W$ in the early Universe. We state the general criteria for charged lepton mixing, critically reexamine aspects of neutrino equilibration and provide arguments to suggest that neutrinos may equilibrate as mass eigenstates in the temperature regime \emph{prior} to flavor equalization. We assume this to be the case, and that neutrino mass eigenstates are in equilibrium with different chemical potentials. Charged lepton self-energies are obtained to leading order in the electromagnetic and weak interactions. The upper bounds on the neutrino asymmetry parameters from CMB and BBN without oscillations, combined with the fit to the solar and KamLAND data for the neutrino mixing angle, suggest that for the two generation case there is resonant \emph{charged lepton} mixing in the temperature range $T \sim 5 \mathrm{GeV}$. In this range the charged lepton oscillation frequency is of the same order as the electromagnetic damping rate.Comment: 17 pages, 2 figs, same results with more discussions on quantum Zeno effect. To appear in Astroparticle Physic

Decay constants and radiative decays of heavy mesons in light-front quark model

We investigate the magnetic dipole decays $V\to P\gamma$ of various heavy-flavored mesons such as $(D,D^*,D_s,D^{*}_s,\eta_c, J/\psi)$ and $(B,B^*,B_s,B^*_s,\eta_b,\Upsilon)$ using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors $F_{VP}(q^2)$ for $V\to P\gamma^*$ decays are obtained in the $q^+=0$ frame and then analytically continued to the timelike region by changing ${\bf q}_\perp$ to $i{\bf q}_\perp$ in the form factors. The coupling constant $g_{VP\gamma}$ for real photon case is then obtained in the limit as $q^2\to 0$, i.e. $g_{VP\gamma}=F_{VP}(q^2=0)$. The weak decay constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations.Comment: 9 pages, 3figures, added few more references, typos correcte

Noncommutative D-Brane in Non-Constant NS-NS B Field Background

We show that when the field strength H of the NS-NS B field does not vanish, the coordinates X and momenta P of an open string endpoints satisfy a set of mixed commutation relations among themselves. Identifying X and P with the coordinates and derivatives of the D-brane world volume, we find a new type of noncommutative spaces which is very different from those associated with a constant B field background.Comment: 11 pages, Latex, minor modification