The QCD Mass Spectrum

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Quantum chromodynamics (QCD) is the theory of physics that describes the strong nuclear force.  The strong force is responsible for binding together protons and neutrons to form atomic nuclei.  However, we now know that protons and neutrons themselves are made up of even smaller particles known as quarks and so, in this light, the strong force ought to be thought of as the interaction responsible for binding quarks together.  Particles like protons and neutrons which are comprised of quarks are collectively referred to as hadrons, and, in the last 75 years, loads of new hadrons have been discovered.  A major goal in particle physics today then is to predict hadron properties from known properties of quarks.  This is a lot tougher than it sounds!  The whole is not simply the sum of the parts here.Currently, my main research interests are in trying to compute masses of hadrons using our current understanding of the quarks that comprise them.  I plan to address this problem using two distinct but complementary approaches.  The first is called lattice QCD and involves running calculations on a supercomputer.  The second technique, QCD sum-rules, is more of of a pencil and paper (and personal computer!) approach to the problem.Computing hadron masses is a central outstanding problem in QCD, and a solution would greatly contribute to our fundamental understanding of the universe.