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:
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 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.
- 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.
- 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 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.