Pion-photon and photon-pion transition form factors in light-cone formalism

We derive the minimal Fock-state expansions of the pion and the photon wave functions in light-cone formalism, then we calculate the pion-photon and the photon-pion transition form factors of $\gamma ^{\ast}\pi ^{0}\to \gamma$ and $\gamma ^{\ast}\gamma \to \pi ^{0}$ processes by employing these quark-antiquark wave functions of the pion and the photon. We find that our calculation for the $\gamma ^{\ast}\gamma \to \pi ^{0}$ transition form factor agrees with the experimental data at low and moderately high energy scale. Moreover, the physical differences and inherent connections between the transition form factors of $\gamma ^{\ast}\pi ^{0}\to \gamma$ and $\gamma ^{\ast}\gamma \to \pi ^{0}$ have been illustrated, which indicate that these two physical processes are intrinsically related. In addition, we also discuss the $\pi ^{0}\to \gamma \gamma$ form factor and the decay width $\mathit{\Gamma}(\pi \to \gamma \gamma)$ at $Q^{2}=0$.Comment: 20 pages, 2 figure

Visible-light induced emulsion photopolymerization with carbon nitride as stabilizer and photoinitiator

Photopolymerization is a common method in the synthesis of polymers with various applications. Herein, a simple and effective route for surfactant-free emulsion photopolymerization (EPP) under visible light irradiation is described. Therein, graphitic carbon nitride (g-CN) was utilized as an stabilizer and a photoinitiator at the same time. As such, g-CN provides the starting point for polymer chain growth and particle formation. Notably, the as-prepared polymer latexes are directly crosslinked by g-CN, and the existence of g-CN is confirmed inside of the particle, as well as outside, where it forms relatively stable latexes. Moreover, surface functionalized g-CN was utilized to tailor the g-CN/monomer interactions for improved particle formation. g-CN quantum dots with enhanced photoluminescence properties were introduced in EPP as well, providing polymer latexes with enhanced photoluminescence. The obtained polymer nanoparticles might be promising candidates for bioimaging applications