Recent progress on the parton distribution functions of the photon, both real and virtual, is briefly reviewed and experimental possibilities at HERA are discussed.

Perturbative QCD corrections to leptoproduction events can be introduced either in the form of matrix elements or of parton showers. Each of these approaches has its advantages and disadvantages, making a comparison of the two interesting. At present energies, both methods can be made to agree reasonably well with data, whereas differences appear at higher energies. The influence of these QCD effe

A number of interrelated topics on jet properties in e+e- annihilation is discussed. The need for different αs values in different fragmentation models is explained, with particular emphasis on the sensitivity to the choice of momentum conservation scheme in independent fragmentation models. Also other factors leading to a broad range of experimental αs values are discussed. Old and new methods to

In perturbative QCD matrix elements, the invariant mass of parton pairs is normally peaked at low values, due to the singularities of the q → qg and g →gg subprocesses. Whereas pairs at large invariant masses give rise to separately visible jets, one may expect a continuous merging back into one single jet, q or g, when the qg or gg invariant mass becomes small. Within the framework of string frag

We study the fragmentation of arbitrary parton configurations, with particular emphasis on events where two partons have a small invariant mass. Within the framework of string fragmentation, a natural transition is obtained between two nearby partons (qg or gg) and a single parton (q or g) carrying the full momentum (provided that colours match), i.e. the final state hadrons are distributed in the

We present a detailed model for exclusive properties of initial state parton showers. A numerically efficient algorithm is obtained by tracing the parton showers backwards, i.e. start with the hard scattering partons and then successively reconstruct preceding branchings in falling sequence of spacelike virtualities Q2 and rising sequence of parton energies. We show how the Altarelli-Parisi equati

After the 2008/2009 global financial crisis, significant policy and scientific attention has been given to ‘green growth’, which aims at the concurrent achievement of economic growth and GHG emissions reductions via de-coupling. Despite ambitious aims, there is a lack of empirical knowledge about the effects and the potential of green growth climate mitigation policies.This thesis aims at providin

Over a 12 year period, the 8π γ-ray spectrometer at the TRIUMF-ISAC facility was a world unique device for β-decay studies. Equipped with a variety of auxiliary devices, it was used in studies of Fermi superallowed β+ emitters, and nuclear structure studies far from stability and those employing high-statistics measurements. In the present contribution, this latter use is highlighted with examples