November 23 - How Does the Proton Spin?
Keith Griffioen, Chair and Professor of Physics, College of William & Mary
Building a proton from quarks has proved far more difficult than
building a hydrogen atom from a proton and an electron. Not only is
the nuclear force that holds the quarks together far stronger than the
electric force, there are three strong charges and only one electric
charge. The mathematics of the proton has, so far, been too tough a
nut to crack. Meanwhile, experiments probing the proton's internal
structure have continued to surprise us. After a decade of
measurements we know that only a third of the proton's spin comes from
the quarks' spin. Throughout the world, physicists are now actively
trying to find the rest. This talk will tell the story for anyone who
has heard of spin-1/2 and who will not be upset by a Fourier Transform.