The X(3872) Files

Eric Braaten
Ohio State

Many new c c-bar mesons have been discovered in recent years that lie
above the charm meson pair threshold and have properties that seem
incompatible with charmonium.  There is one whose structure can be
deduced unambiguously from the current data:  the amazing X(3872).
I will explain what the X(3872) is, but that will not answer the question
of why it is.  I will offer some suggestions for how effective field
theory methods might help answer that question.