Time & Place: June 20, Thursday, 2:00 pm, Room 9409

Speaker: Prof.  Sammuel B. Emmons, Carson-Newman University

Title:  Nuclear polarization effects in muonic deuterium

Abstract:
Certain nuclear properties may be determined from precise spectroscopic
measurements of atomic level spacings. For atoms such as electronic or
muonic hydrogen or deuterium, the spectroscopic measurement of the 2S-2P
Lamb shift is a good path to arrive at an estimate of a finite nuclear
size. However, in such a measurement, three different quantities make
contributions, and experiments cannot untangle them from each other. The
three contributions to the Lamb shift come from the effects of QED, the
finite size of the nucleus, and two-photon-exchange (TPE) between the
orbiting lepton and the nucleus. If one desires to know the finite
mean-square charge radius, theoretical calculations of the QED and TPE
contributions must be made, and the precision with which one knows the
radius from the Lamb shift calculation will be limited by the
uncertainties in these other calculations. The QED contributions to the
Lamb shift are known very precisely. Calculations of the TPE part of the
Lamb shift have been made for several light nuclei, including muonic
deuterium. We present some early results in our efforts to make a new
calculation of the portion of the TPE correction coming from the
polarization of the nucleus in muonic deuterium. We utilize pionless
effective field theory (EFT), which has the promise of providing a
systematic way of reducing error in the TPE shift estimate.