Physics Seminar - FIU PhD students colloquium
This is a past event.
Friday, November 20 at 1:00pm to 2:15pmVirtual Event
"PHOTO-PRODUCTION OF η MESONS"
The GlueX experiment studies the light meson spectrum and searches for hybrid and exotic mesons. As part of the GlueX program, photo-production cross sections of η mesons have been measured in the γ + p → η + p reaction in a new, previously unexplored regime of higher beam energy and smaller production polar angles. This will provide new information about the underlying reaction mechanisms. η mesons have been identified through their γγ decay channel which has a branching ratio of 39.41%. Besides the high energy data, an additional set of low energy photo-production data has been collected that are overlapping with previously published data. Differential cross sections for center of mass energies between 2.52 and 4.75 GeV will be presented. The results at the low center of mass energies will be compared to previously published data and all results will be compared with recent model calculations.
“The Structure of the Deuteron at Very Short Distance”
We study (quasi-elastic) deuteron electrodisintegration as a probe for a number of phenomena relevant to short distance structure in nuclei. In this reaction an electron hits a nucleus of deuterium, which breaks up into a pair of nucleons (proton-neutron). We focus our attention on events where very fast nucleons emerge, which can be traced back to configurations where the bound nucleons had high relative momentum (exceeding 700 MeV/c).
Many of the difficulties inherent to the relativistic nature of the processes involved are simplified by adopting a framework known as Light Front dynamics. These include a consistent treatment of the relativistic spinor-spinor bound state wave function, the bound nucleon electromagnetic current, and the interaction between the emerging nucleons in the final state of the scattering. Our calculation of deuteron’s relativistic wave function shows the appearance of a structure related to the off-shell properties of the bound state, which does not appear in non-relativistic quantum mechanics. The contribution of this term, of relativistic origin, becomes increasingly important at high relative momentum of the bound nucleons. This new theoretical calculation can bring important insight on the relativistic structure of nuclear matter. A comparison with the first experimental data that are not dominated by final state interactions, which has become recently available from Jefferson Lab, is still under study.