IMSc Webinar

(g-2) of the Muon: Theory and Experiment Challenge One Another

B. Ananthanarayan

CHEP, Indian Institute of Science

The muon is a heavy cousin of the electron and has a gyromagnetic
ratio of 2 in the classical limit, which was predicted by Dirac. In QED it
receives an anomalous magnetic moment which was
computed by Julian Schwinger at leading order. Today, in QED it is evaluated
to very high loop order, and also receives corrections from virtual processes
in the vacuum as dictated by the laws of
quantum field theory, which have to be evaluated in a variety of ways. It is
also measured at high precision today at Fermilab, whose recent results
confirm the value measured at Brookhaven about 20
years ago. More data is being gathered to lower the uncertainty. The
theoretical value which is known at high precision deviates from the
experimental measurement at several standard deviations. The
quantity is also measured on the lattice with larger errors. In this talk,
meant for a non-specialist audience, we will review these developments. Time
permitting, we will speak about our own work
that has played a role in lowering the uncertainties in the theoretical
hadronic vacuum polarization contributions.