Lattice QCD
Quantum Chromodynamics (QCD) describes the interactions of quarks and gluons (by the force of Nature called the strong force) and predicts in principle the masses of their bound states (called hadrons). The calculation of hadron masses, however, can only be done by the numerical simulation of QCD on a lattice of space-time points. It is designated internationally as a "Grand Challenge" project, testing the fastest supercomputers that we have.
Research at Glasgow
Glasgow is part of the HPQCD collaboration (Cornell, Fermilab, Glasgow, Ohio State University, Simon Fraser University) who have recently teamed up with the MILC collaboration to make some significant progress towards this. We have been able, for the first time, to simulate something approaching the real world and, as a result, we have calculated masses for a range of hadrons (these include the Upsilon particle, the J/psi, the omega baryon, the B meson etc) and obtained answers in agreement with experiment at the few percent level. The key change is that the calculations have included the effects of energy fluctuations that create gluons and quark-antiquark pairs for a short time. This is computationally very hard but necessary to get the right answers. We are now continuing this work to calculate results for different decay rates of the B meson needed by the current B factory experimental programmes at Cornell, Stanford and KEK, Japan.
Further Reading
Joining up the dots with the strong force Cover feature in CERN courier, June 2004.
Getting to Grips with the Strong Force, Physics World, August 2000, pp35-40.
New Scientist: Inside Science no. 63, World of Quarks, 10th July 1993.
Summer school lectures at the 55th Scottish Universities Summer School, St Andrews, August 2001. Suitable for graduate students in experimental or theoretical particle physics.