DeTar's Research Program in Plain Language

Quarks and gluons make up protons and neutrons and many other elementary particles. My research deals with the interactions of quarks and gluons. Understanding their interactions helps advance science in several ways:
  1. The early universe was filled with a novel form of matter, namely a vast plasma of quarks and gluons. Knowing the properties of such a plasma helps us understand the very origins of our universe.
  2. Our present understanding of the most fundamental interactions and particles in nature is summarized in the "Standard Model". We are certain this model is incomplete. For example, it doesn't explain the dark matter that pervades the universe. So we know there are more fundamental processes and particles. To discover them, we build and operate very high energy accelerators, such as the Tevatron at Fermilab in Illinois and the LHC (Large Hadron Collider) in Europe. But we need a thorough and accurate understanding of the interactions of quarks and gluons in order to make new discoveries.
  3. The cores of very dense stars contain an unusual form of matter consisting of highly compressed neutrons. Solving QCD helps us understand the properties of such stars.
The well-accepted theory of interacting quarks and gluons is called quantum chromodynamics, or just "QCD". Although QCD is a relatively simple theory, except in special circumstances, it has resisted attempts to find solutions using standard pencil-and-paper methods. Numerical solutions are possible, however, and with the dramatic increase in computing technology and equally important advances in computational methods, we are now able to obtain impressively accurate results for some quantities, such as the mass of the proton.

The Utah lattice gauge theory group collaborates with theorists worldwide, and it carries out its calculations on the most powerful computers in the US.
Precision test of the Standard Model. The plot shows two parameters of the Standard Model. They are determined from experimental measurements. Each band represents a different measurement, which gives a different range of possible values for the two parameters. Theoretical calculations like ours are required in order to get these parameters from the experiment. If the Standard Model is correct, the colored bands must intersect at a common point. That point is shown as a tiny black ellipse. This figure shows the status of the test as of 2015. So far, everything looks pretty consistent with the Standard Model. More precise experiments and theoretical calculations are currently under way. They will make the bands shrink, tighten the noose, and, perhaps, expose an inconsistency that will point us to new, more fundamental particles and processes.