Over 30 years ago, the discovery of charmonium (a bound state of charm and anti-charm quarks) helped establish Quantum Chromodynamics (QCD) as the correct theory of the strong interactions. Today, charmonia and other hadrons composed of charm quarks are produced and studied in high energy experiments around the world. In the past few years, experimentalists have discovered a large number of new charmed hadrons and observed anomalies in the production of well-established charmonia that were not anticipated by theorists. Notable among the recently discovered states is the X(3872), which is thought to be the first example of a molecular hadron whose constituents are charmed mesons.
This colloquium will focus on using effective field theories to better understand the physics of these charmed hadrons. Important results include new factorization theorems for the production of the J/Ψ, elucidating the nature of excited charmed strange mesons, and a new effective theory for the X(3872).
I will begin with a brief review of QCD, and then describe the basic ideas underlying the effective field theory approach to QCD phenomenology. I will then describe applications to these topical problems in the physics of charm quarks.
Coffee and cookies before the presentation at 3:15 pm, and refreshments after the presentation will both be served in Room 128.