Visualization of Rosenbluth Separations

The electromagnetic form factors of the proton can be determined by making measurements at the same four momentum transfer, Q², but with different beam energies. This is a technique known as a Rosenbluth separation. The results of this type of measurement are typically plotted as the reduced cross-section against the values of epsilon, a value calculated from the beam energy and scattering angle, and fitting a line to the data; but this method makes it very hard to see the physical quantities of interest from such a plot. Back in the late 60’s, Nobel laureate Robert Hofstadter proposed a different way to visual Rosenbluth data. In this talk we will use classic SLAC elastic scattering data to show these two different ways of presenting the data and illustrate the value of Hofstadter’s visualization technique.