High Energy Asymptotics Research Articles

Pressure-Velocity Correlation in a Reactive Turbulent Flow

Analysis is made of the often-neglected correlation between velocity and pressure gradient fluctuations which occurs in the turbulent kinetic energy equation (TKEE). Restricting attention to this correlation for normal turbulent flames in premixed gases using high activation energy asymptotics, a model is generated for the correlation. Splitting the velocity field into solenoidal and irrotational components, it is shown that the acoustic field can dominate the vortical field under several circumstances, in which case the TKEE is not a turbulence equation but an acoustic equation. Under conditions where the vortical field is dominant the pressure-velocity correlation is shown to be essential to the TKE balance.

Next-to-leading logarithms in the high-energy asymptotics of the quark form factor and the jet cross section

The logarithms ∼ α s n ln 2 n ( Q 2/ μ 2) and ∼ α s n ln 2 n−1 ( Q 2/ μ 2) in the asymptotics of the quark form factor in the Sudakov region Q 2 = | q 2|>| p 2| = | p′ 2| = μ 2 are summed. We get the simple result S(Q 2, μ 23) = exp − α s(μ 2 2φ C F 1n 2 Q 2 μ 2 + 3α s(μ 2)C F 4φ 1n Q 2 μ 2 The same expression S( Q 2, M 2) describes the jet cross section in the e + e −→ q q process where the jet is defined as a set of particles whose total invariant mass does not exceed M 2. The QCD predictions are compared with the experimental data available and the jets observed are shown to be much broader than QCD predicts.

The renormalization group and ultraviolet asymptotics

This article describes in detail the method of the renormalization group and outlines the possibilities of using it for the analysis of high-energy asymptotics in the framework of quantum field theory. The renormalization group formalism is constructed for an arbitrary scheme of renormalization. The exposition is based on the concepts of effective charge and effective mass. Principal attention is given to the problem of deriving reliable information about the ultraviolet properties of quantized-field models on the basis of perturbation theory calculations. A summary of the results of such calculations for a wide variety of models is given.