We derive generic relativistic hydrodynamical equations with dissipative effects from the underlying Boltzmann equation in a mechanical and systematic way on the basis of so called the renormalization-group method. A macroscopic frame vector is introduced to specify the frame on which the macroscopic dynamics is described. Our method is so mechanical with only few ansatz that our method give a microscopic foundation of the available hydrodynamical equations, and also can be applied to make a reduction of the kinetic equations other than the simple Boltzmann equation.

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We consider the three flavor Nambu-Jona-Lasinio model with the 't Hooft interaction incorporating the U(1) A anomaly. In order to set the coupling strength of the 't Hooft term, we employ the topological susceptibility χ instead of the η ′ meson mass. The value for χ is taken from lattice simulations.We also calculate χ at finite temperature within the model. Comparing it with the lattice data, we extract information about the behavior of the U(1) A anomaly at finite temperature. We conclude that within the present framework, the effective restoration of the U(1) A symmetry does not necessarily take place even at high temperature where the chiral symmetry is restored.11.30. Rd, 12.39.Fe

We propose the enhancement of Lambdac as a novel quark-gluon plasma signal in heavy ion collisions at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider. Assuming a stable bound diquark state in the strongly coupled quark-gluon plasma near the critical temperature, we argue that the direct two-body collision between a c quark and a [ud] diquark would lead to an enhanced Lambdac production in comparison with the normal three-body collision among independent c, u, and d quarks. In the coalescence model, we find that the Lambdac/D yield ratio is enhanced substantially due to the diquark correlation.

We calculate the shear viscosity (η) to entropy density (s) ratio η/s of a gluon plasma in kinetic theory including the gg → gg and gg → ggg processes. Due to the suppressed contribution to η in the gg → gg forward scattering, it is known that the gluon bremsstrahlung gg ↔ ggg process also contributes at the same order (O(α −2 s )) in perturbative QCD. Using the Gunion-Bertsch formula for the gg → ggg matrix element which is valid for the limit of soft bremsstrahlung, we find that the result is sensitive to whether the same limit is taken for the phase space. Using the exact phase space, the gg ↔ ggg contribution becomes more important to η than gg → gg for α s 2 × 10 −3 . Therefore, at α s = 0.1, η/s ≃ 1.0, between 2.7 obtained by Arnold, Moore and Yaffe (AMY) and 0.5 obtained by Xu and Greiner. If the soft bremsstrahlung limit is imposed on the phase space such that the recoil effect from the bremsstrahlung gluon is neglected, then the correction from the gg ↔ ggg process is about 10-30% of the total which is close to AMY's prediction. This shows that the soft bremsstrahlung approximation is not as good as previously expected.