Hadrons Without Strings

Descriptions of hadrons and glueballs can be constructed using strings to preserve gauge invariance. We show how this string dependence may be removed to all orders in perturbation theory.Comment: 11 pages, 3 figures, LaTe

The Glue Around Quarks and the Interquark Potential

The quarks of quark models cannot be identified with the quarks of the QCD Lagrangian. We review the restrictions that gauge field theories place on any description of physical (colour) charges. A method to construct charged particles is presented. The solutions are applied to a variety of applications. Their Green's functions are shown to be free of infra-red divergences to all orders in perturbation theory. The interquark potential is analysed and it is shown that the interaction responsible for anti-screening results from the force between two separately gauge invariant constituent quarks. A fundamental limit on the applicability of quark models is identified.Comment: 4 pages, LaTeX, talk given at Montpellier meeting QCD9

The Colour of Quarks

It is shown that colour can only be defined on gauge invariant states. Since the ability to associate colour with constituent quarks is an integral part of the constituent quark model, this means that, if we want to extract constituent quarks from QCD, we need to dress Lagrangian quarks with gluons so that the result is gauge invariant. We further prove that gauge fixings can be used to construct such dressings. Gauge invariant dressed quark states are presented and a direct approach to the interquark potential is discussed. Some further aspects of dressing quarks are briefly discussed.Comment: Extended version, to appear in Phys. Lett B., 7 pages, Te

Replacement of traditional lectures with computer‐based tutorials: A case study

A set of computer‐based tutorial files were produced in‐house and used to replace two traditional lectures. Students submitted feedback on their use of the CAL material. The ease of production and delivery, and the positive responses from the students, have provided justification for further development of in‐house CAL material. Further insights are given into the integration of CAL into a curriculum

The availability of declaratory relief

In spite of the unequivocal decision of the ECJ in The Front Comor [2009] 1 Lloyd’s Rep 413 that anti-suit injunctions are incompatible with the Regulation and fundamentally, the principle of mutual trust, the Court of Appeal in National Navigation Co v Endesa [2009] EWCA Civ has controversially opined that declarations of validity may be used as grounds for non-recognition of a foreign judgment where the declaration is given prior to the foreign court’s decision. This reading however is unlikely to be favourable in Europe, as declarations may now be seen as having the same adverse effect as anti-suit injunctions

The Physical Propagator of a Slowly Moving Charge

We consider an electron which is electromagnetically dressed in such a way that it is both gauge invariant and that it has the associated electric and magnetic fields expected of a moving charge. We study the propagator of this dressed electron and, for small velocities, show explicitly at one loop that at the natural (on-shell) renormalisation point, $p_0=m$, ${\bold p}= m{\bold v}$, one can renormalise the propagator multiplicatively. Furthermore the renormalisation constants are infra-red finite. This shows that the dressing we use corresponds to a slowly moving, physical asymptotic field.Comment: 10 pages, plain TeX, 1 Figure (uuencoded needs epsfig.sty

Electrons and Photons: Fact not Fiction

The particle Fock space of the matter fields in QED can be constructed using the free creation and annihilation operators. However, these particle operators are not, even at asymptotically large times, the modes of the matter fields that enter the QED Lagrangian. In this letter we construct the fields which do recover such particle modes at large times. We are thus able to demonstrate for the first time that, contrary to statements found in the literature, a relativistic description of charged particles in QED exists.Comment: 8 pages, LaTe