Radiative πρ\pi \rho and πω\pi \omega transition form factors in a light-front constituent quark model

The form factors of the $\pi \rho$ and $\pi \omega$ radiative transitions are evaluated within a light-front constituent quark model, using for the first time the eigenfunctions of a light-front mass operator reproducing the meson mass spectrum and including phenomenological Dirac and Pauli quark form factors in the one-body electromagnetic current operator. The sensitivity of the transition form factors both to the meson wave functions and to the constituent quark form factors is illustrated. It is shown that the measurement of the $\pi \rho$ and $\pi \omega$ radiative transitions could help in discriminating among various models of the meson structure.Comment: 9 pages, latex, 4 figures available as separate .uu file, to appear in Phys. Lett.

Hard Constituent Quarks and Electroweak Properties of Pseudoscalar Mesons

The high momentum components generated in the wave function of pseudoscalar mes* by the one-gluon-exchange interaction are investigated within a relativistic constituent quark model. Adopting the light-cone formalism, the sensitivity of the weak decay constant and the charge form factor to hard constituent quarks is illustrated.Comment: 11 pages and 5 figs. (to be requested), LaTeX, INFN-ISS 94/3. To appear in Physics Lett.

Nucleon and pion electromagnetic form factors in a light-front constituent quark model

Nucleon and pion electromagnetic form factors are evaluated in the spacelike region within a light-front constituent quark model, where eigenfunctions of a mass operator, reproducing a large set of hadron energy levels, are adopted and quark form factors are considered in the one-body current. The hadron form factors are sharply affected by the high momentum tail generated in the wave function by the one-gluon-exchange interaction. Useful information on the electromagnetic structure of light constituent quarks can be obtained from the comparison with nucleon and pion experimental data.Comment: 9 pages, latex, 4 figures available as separate .uu fil

The running coupling method with next-to-leading order accuracy and pion, kaon elm form factors

The pion and kaon electromagnetic form factors $F_M(Q^2)$ are calculated at the leading order of pQCD using the running coupling constant method. In calculations the leading and next-to-leading order terms in $\alpha_S((1-x)(1-y)Q^2)$ expansion in terms of $\alpha_S(Q^2)$ are taken into account. The resummed expression for $F_M(Q^2)$ is found. Results of numerical calculations for the pion (asymptotic distribution amplitude) are presented.Comment: 9 pages, 1 figur

Charge form factor of π\pi and KK mesons

The charge form factor of $\pi$ and $K$ mesons is evaluated adopting a relativistic constituent quark model based on the light-front formalism. The relevance of the high-momentum components of the meson wave function, for values of the momentum transfer accessible to $CEBAF$ energies, is illustrated. The predictions for the elastic form factor of $\pi$ and $K$ mesons are compared with the results of different relativistic approaches, showing that the measurements of the pion and kaon form factors planned at $CEBAF$ could provide information for discriminating among various models of the meson structure.Comment: 8 pages, latex, 4 figures available as separate .uu fil

Pion Form Factor in the NLC QCD SR approach

We present results of a calculation of the electromagnetic pion form factor within a framework of QCD Sum Rules with nonlocal condensates and using a perturbative spectral density which includes \mathcal{O}(\alpha_s) contributions.Comment: 9 pages, 2 figures (embedded). Talk presented by the second author at the Workshop on Physics of Fundamental Interactions, Institute of High Energy Physics, Protvino, Russia, 22--25 December 200

Pair term in the Electromagnetic Current within the Front-Form Dynamics: Spin-0 Case

The frame and scale dependence of the pair-term contribution to the electromagnetic form factor of a spin-zero composite system of two-fermions is studied within the Light Front. The form factor is evaluated from the plus-component of the current in the Breit frame, using for the first time a nonconstant, symmetric ansatz for the Bethe-Salpeter amplitude. The frame dependence is analyzed by allowing a nonvanishing plus component of the momentum transfer, while the dynamical scale is set by the masses of the constituents and by mass and size of the composite system. A transverse momentum distribution, associated with the Bethe-Salpeter amplitude, is introduced which allows to define strongly and weakly relativistic systems. In particular, for strongly relativistic systems, the pair term vanishes for the Drell-Yan condition, while is dominant for momentum transfer along the light-front direction. For a weakly relativistic system, fitted to the deuteron scale, the pair term is negligible up to momentum transfers of 1(GeV/c)$^2$. A comparison with results obtained within the Front-Form Hamiltonian dynamics with a fixed number of constituents is also presented.Comment: 25 pages + 7 figures; axodraw.sty included. To appear in Nucl. Phys.

Pionic Degrees of Freedom in Atomic Nuclei and Quasielastic Knockout of Pions by High-Energy Electrons

The nonlinear model of pionic condensate in nuclei by G. Preparata can be efficiently verified by investigation of the quasielastic knockout process of pions out of nuclei by high energy electrons. First, a momentum distribution (MD) of the collective pions has a bright maximum at q=0.3 Gev.Second the excitation spectrum of a recoil nucleus is concentrated at low energies E lesser than 1MeV. The results for the pion knockout from mesonic clouds of individual nucleons are absolutely different. The latter results are presented both for pion and rho-meson clouds localized on nucleons.Comment: 13 pages, 3 figure

Brokering intercultural relations in the rainbow nation: introducing intercultural marketing

This paper considers the role of marketing in building intercultural relations in superdiverse, post-colonial societies, using post-apartheid South Africa as a case study. Drawing on neo-institutional theory, we analyze South African advertising campaigns to determine how marketing brokers intercultural relations by legitimizing social meanings conveyed through nation-building ideologies and consumers’ lived experiences. We examine whether marketing outputs align with stages of Rainbow Nation-building strategies and types of consumers’ lived experiences of South Africa’s superdiversity. We then derive a conceptualization of intercultural marketing, which we characterize as an approach focused on brokering meanings of convivial intercultural engagement and collective development of societal welfare goals. We contribute to macromarketing theory, directing attention to the important brokering role marketing has, in bridging conceptions of reconciliatory social development held by public policy makers and by societies’ populations. By conceptualizing intercultural marketing, its goals and tools, we contribute to multiculturally-sensitive marketing research and practice advancement