Tackling the infrared problem of thermal QCD

Perturbative calculations of corrections to the behavior of an ideal gas of quarks and gluons, the limit that is formally realized at infinite temperature, are obstructed by severe infrared divergences. The limits to computability that the infrared problem poses can be overcome in the framework of dimensionally reduced effective theories. Here, we give details on the evaluation of the highest perturbative coefficient needed for this setup, in the continuum.Comment: 3 pages, Lattice2003(nonzero

Evading the Infrared Problem of Thermal QCD

Due to asymptotic freedom, QCD is guaranteed to be accessible to perturbative methods at asymptotically high temperatures. However, in 1979 Linde has pointed out the existence of an "infrared wall", beyond which an infinite number of Feynman diagrams contribute. Following a proposal by Braaten and Nieto, it is shown explicitly how the limits to computability that this infrared problem poses can be overcome in the framework of dimensionally reduced effective theories.Comment: To appear in the proceedings of SEWM04, Helsinki, Finland, 16-19 Jun 200

Long-distance contributions to the QCD pressure

The QCD pressure is a most fundamental quantity, for which lattice data is available up to a few times the critical temperature $T_c$. Perturbation theory, even at very high temperatures, has serious convergence problems. Combining analytical and 3d numerical methods, we show that it is possible to compute the QCD pressure from about $2 T_c$ to infinity. We also describe an algorithm to generate and classify high order Feynman diagrams which is tailored to minimize computational effort.Comment: 5 pages; talk at Statistical QCD, Bielefeld, August 26-30, 200

Weak-coupling expansion of the hot QCD pressure

We review recent progress made in determining the pressure of hot QCD up to the first non-perturbative term in its weak-coupling expansion.Comment: 11 pg, Talk given at 29th Johns Hopkins Workshop in Theoretical Physics: Strong Matter in the Heavens, Budapest, Hungary, 1-3 Aug 200

Loops for Hot QCD

In this talk we review the status concerning vacuum integrals needed in perturbative expansions of QCD at non-zero temperature. We will focus on the differences as compared to familiar zero-temperature techniques, and provide a list of known basic master integrals.Comment: 6 pages, to appear in the proceedings of the international conference on Loops and Legs in Quantum Field Theory, Sondershausen, 20-25 April 200

Two-loop QCD gauge coupling at high temperatures

We determine the 2-loop effective gauge coupling of QCD at high temperatures, defined as a matching coefficient appearing in the dimensionally reduced effective field theory. The result allows to improve on one of the classic non-perturbative probes for the convergence of the weak-coupling expansion at high temperatures, the comparison of full and effective theory determinations of an observable called the spatial string tension. We find surprisingly good agreement almost down to the critical temperature of the deconfinement phase transition. We also determine one new contribution of order O(g^6T^4) to the pressure of hot QCD.Comment: 17 page

Feasibility of Using Cryostored Colorado Potato Beetle (Coleoptera: Chrysomelidae) Eggs for Rearing \u3ci\u3eEdovum Puttleri\u3c/i\u3e (Hymenoptera: Eulophidae)

Cryostored eggs of Colorado potato beetle, Leptinotarsa decemlineata (Say) eggs were suitable hosts for Edovum puttleri. Parasitism rates were low, however this study was first to show that rearing the parasite on eggs stored at ultra low temperatures (-70 0 C) is feasible. This method of storage will facilitate mass production of E. puttleri as well as prevent loss of the parasite in the event of a crash in the Colorado potato beetle colony