Ordering variable for parton showers

The parton splittings in a parton shower are ordered according to an ordering variable, for example the transverse momentum of the daughter partons relative to the direction of the mother, the virtuality of the splitting, or the angle between the daughter partons. We analyze the choice of the ordering variable and conclude that one particular choice has the advantage of factoring softer splittings from harder splittings graph by graph in a physical gauge.Comment: 28 pages, 5 figure

The effect of waste logistics on the environmental impact of road transport

Nowadays we should consider the wastes in a much wider sense as an expedient raw material source. From a logistic point of view the fact that the flows of the second raw materials are not constant in the waste logistics systems is a challenge. The quantity of the wastes of production, consumption and recycling are varying in time and space. The arising municipal wastes usually can be found in smaller items then previously, have relatively more utilization opportunity when they appear separated on the refuse dumps. Optimal cargos should be organized by the environmental aspect of road transport services. Recently road transport is one of the main polluters. With the internalisation of external costs of road transportation the price of waste as basis of secondary raw material will increase. The article describes these problems and the methods of which can be used for the solution

Phase structure of the O(2)O(2) ghost model with higher-order gradient term

The phase structure and the infrared behaviour of the Euclidean 3-dimensional $O(2)$ symmetric ghost scalar field model with higher-order derivative term has been investigated in Wegner and Houghton's renormalization group framework. The symmetric phase in which no ghost condensation occurs and the phase with restored symmetry but with a transient presence of a ghost condensate have been identified. Finiteness of the correlation length at the phase boundary hints to a phase transition of first order. The results are compared with those for the ordinary $O(2)$ symmetric scalar field model.Comment: 15 pages, 13 figure

Multi-jet cross sections in deep inelastic scattering at next-to-leading order

We present the perturbative prediction for three-jet production cross section in DIS at the NLO accuracy. We study the dependence on the renormalization and factorization scales of exclusive three-jet cross section. The perturbative prediction for the three-jet differential distribution as a function of the momentum transfer is compared to the corresponding data obtained by the H1 collaboration at HERA.Comment: 5 pages, 3 figure