College of Science

"Heavyweights battle to expose the naked quark"

Purdue Physics Professor Ian Shipsey was interviewed for the article "Heavyweights battle to expose the naked quark" in issue 2512 of New Scientist magazine, 13 August 2005, page 33. The article tells the story of a breakthrough in Lattice QCD a method for calculating the strong nuclear force and a particle physics experiment, CLEO-c at Cornell, of which Ian Shipsey is one of the leading members, that tests the Lattice calculations.

The strong force is an essential ingredient of our world. Without it, the atomic nucleus, and the protons and neutrons in the nucleus, would fall apart. It is the strong force that contributes most of the mass to the matter of which stars planets and humans are made. Until recently, almost all of the Lattice calculations have been devoted to reproducing strong force effects in sub atomic particles that had been measured years previously. However, last year, in a relatively straightforward calculation by Lattice standards (it took two years on a supercomputer) for the first time the mass of a subatomic particle was successfully predicted just before the mass was measured. [See I. Shipsey Nature 436, 186-187 (14 July, 2005) ]. On June 28 2005 in an even more challenging calculation a strong force effect on the radioactive disintegration rate of a subatomic particle was completed. Just 48 hours later the same effect was measured. by CLEO-c and the calculation and measurement agree. Further similar calculations are underway for disintegration rates where the strong force effect cannot be measured experimentally but must be taken into account before the disintegration rates, which are very sensitive to new physical phenomena, can be compared to theory. Within several years these strong force effects will be calculated and the data can then be fully interpreted for the first time. If the data do not conform to the Standard Model of particle physics, it could provide hints about new physical phenomena such as hidden dimensions of space, explain why the electric charge on an electron is exactly opposite the charge of a proton, why a top quark is 360,000 time more massive than an electron, and why there is matter in the Universe.

http://www.newscientist.com/article/mg18725121.800.html