Analysis of ω\omega self-energy at finite temperature and density in the real-time formalism

Using the real time formalism of field theory at finite temperature and density we have evaluated the in-medium $\omega$ self-energy from baryon and meson loops. We have analyzed in detail the discontinuities across the branch cuts of the self-energy function and obtained the imaginary part from the non-vanishing contributions in the cut regions. An extensive set of resonances have been considered in the baryon loops. Adding the meson loop contribution we obtain the full modified spectral function of $\omega$ in a thermal gas of mesons, baryons and anti-baryons in equilibrium for several values of temperature and baryon chemical potential

Shear viscosity of pion gas due to ρππ\rho\pi\pi and σππ\sigma\pi\pi interactions

We have evaluated the shear viscosity of pion gas taking into account its scattering with the low mass resonances, $\sigma$ and $\rho$ during propagation in the medium. The thermal width (or collisional rate) of the pions is calculated from $\pi\sigma$ and $\pi\rho$ loop diagrams using effective interactions in the real time formulation of finite temperature field theory. A very small value of shear viscosity by entropy density ratio ($\eta/s$), close to the KSS bound, is obtained which approximately matches the range of values of $\eta/s$ used by Niemi et al. \cite{Niemi} in order to fit the RHIC data of elliptic flow.Comment: 7 pages, 8 figure

NO₂-induced synthesis of nitrato-iron(III) porphyrin with diverse coordination mode and the formation of isoporphyrin

Two nitrato-iron(III) porphyrinates [Fe(4-Me-TPP)(NO3)] 1 and [Fe(4-OMe-TPP)(NO3)] 2 are reported. Interestingly, [Fe(4-Me-TPP)(NO3)] 1 has nitrate ion coordinated as monodentate (by single oxygen atom), while [Fe(4-OMe-TPP)(NO3)] 2 has nitrate coordination through bidentate mode. Compound 1 was found serendipitously in the reaction of [Fe(4-Me-TPP)Cl] with nitrous acid, which was performed for the synthesis of nitro-iron(III) porphyrin, [Fe(4-Me-TPP)NO2]. The compound 2 was synthesized by passing NO2 gas through a solution of [Fe(4-OMe-TPP)]2O. Upon passing NO2 gas through a solution of a μ-oxo-dimer, [Fe(4-Me-TPP)]2O also produces 1. It is interesting that in more electron-rich porphyrin 2, binding of the nitrate in a symmetrical bidentate way while in less electron-rich porphyrin 1, binding of the anion is unidentate by a terminal oxygen atom. However, it is expected that the energy difference between the monodentate and bidentate coordination mode is very small and the interchange between these coordination is possible. Upon passing NO2 gas through a solution of μ -oxo-dimeric iron(III) porphyrin, the nitrato-iron(III) porphyrin forms first, that later gets oxidized to π-cation radical to yield hydroxy-isoporphyrin in the presence of trace amount of water. These nitrato-iron(III) porphyrinates in moist air slowly converted back to their respective μ -oxo-dimeric iron(III) porphyrins

Dragging DD mesons by hot hadrons

We evaluate the drag and diffusion coefficients of a hot hadronic medium consisting of pions, nucleons, kaons and eta using open charm mesons as a probe. The interaction of the probe with the hadronic matter has been treated in the framework of effective field theory. It is observed that the magnitude of both the transport coefficients are significant, indicating substantial amount of interaction of the heavy mesons with the thermal hadronic system. The results may have noticeable impact on the experimental observable like the suppression of single electron spectra originating form the decays of heavy mesons in nuclear collisions at relativistic energies.Comment: One Latex and three eps files, form factor effects include