[PAST EVENT] Physics Colloquium

February 7, 2013
4pm - 5pm
Small Hall, Room 111
300 Ukrop Way
Williamsburg, VA 23185Map this location
Today, protons and neutrons are understood to be composed of quarks and gluons, and Quantum Chromodynamics (QCD) is the accepted fundamental theory of quark-gluon dynamics. Ultimately, QCD underlies all strong nuclear interactions, including those responsible for binding protons and neutrons into the atomic nuclei of everyday matter.

QCD has shown remarkable success over the past several decades in describing high energy hadronic collisions. Methods of perturbative QCD in particular are now basic tools of high energy particle phenomenology. In spite of these successes, however, the standard perturbative QCD formalism, called "collinear factorization," has a limited range of applicability. Many studies of the quark and gluon structure of hadrons require new and extended perturbative QCD formalisms. For instance, high energy processes that are sensitive to the intrinsic internal motion of bound state quarks and gluons require a modified perturbative QCD formalism called "transverse momentum dependent (TMD) factorization."

In my talk, I will give an overview of the standard collinear perturbative QCD formalism and explain how it must be extended in order to accommodate the intrinsic motion of quarks and gluons inside colliding hadrons. Next, I will describe my recent work in applying this formalism and discuss future plans to develop more advanced implementations which, when combined with data from current and planned experiments, may yield rich and detailed information about the structure of strongly interacting particles.

I will end by presenting a summary of my recent work on the identification of surprising situations where the classic picture of quark-gluon interactions in high energy collisions fails in perturbative QCD.