D(γ,n)H: Photodisintegration of the Deuteron at 18 MeV using Linearly Polarized Photons

Speaker: Glen Pridham
Location: Physics 175
Time: 3:30pm, June 12th, 2014

(Update) You can view the presentation here.

Abstract: The deuteron is probably the simplest nuclear system: it is composed of two (composite) particles and has only one bound state.  As such, it has long served as the first test case for new experimental and theoretical methods.  Although the deuteron is important on its own merit (e.g. for fusion), precision measurements and calculations also serve to enhance the accuracy of nucleon­nucleon potentials which, in turn, improve the accuracy of all nuclear calculations.

Despite its simplicity: deuteron photodisintegration has a history of inconsistent experimental results, which began being cleaned up in the late 1980s with the advent of monochromatic photon sources (i.e. free­ electron lasers and Compon laser scattering beams).  Concurrently, the use of retarded Green`s functions and realistic meson exchange potentials in modelling the nuclear force served to greatly enhance theoretical accuracy.  The pursuit of an experimental and theoretical consensus on deuteron photodisintegration continues to this day: gradually mapping out the energy landscape.

In this seminar, I will present the results of a deuteron photodisintegration experiment performed in October 2010 at the High­Intensity Gamma Source (HIγS) Free­Electron Laser (FEL) at Duke University in Durham, North Carolina.  These results are compared to a recent calculation by Schwamb and Arenhӧvel who used a one meson exchange nucleon­nucleon potential with delta baryon intermediate states, relativistic corrections, and retarded Green`s functions.

I will include an overview of the use of mesons as the effective quark degrees of freedom in the nuclear regime; which allows the nuclear force to be rigorously modelled as the exchange of virtual mesons.

Coupling the Higgs Boson to the Nucleon

Who (supervisor): Fred Sage (Rainer Dick)
Venue: PEGASUS Student Summer Seminar, Aug 9, 2012.
Abstract: The talk will explore possible methods of computing an effective Higgs-nucleon coupling. While the interaction of the Higgs with fundamental particles in the Standard Model of particle physics is well understood, how it couples to composite particles like the nucleon is less well understood. The physics of the Higgs boson itself will be reviewed, and then previous attempts at finding such a coupling will be discussed. Finally, several potential new methods will be given brief descriptions.