Published in Phys. Lett. B: “Comparing proton momentum distributions in A = 2 and 3 nuclei via 2H, 3H, and 3He (e,e’p) measurements”

The Journal “Physics Letters B” has just published our paper measuring (e,e’p) cross section ratios in deuterium, tritium, and Helium-3 using the Jefferson Lab Hall A high resolution spectrometers. This experiment was part of the “Tritium Run Group” at Jefferson Lab, a once in a generation opportunity to perform electron-scattering experiments on the radioactive isotope of hydrogen with one proton and two neutrons. Tritium decays with a half life of about 12 years, which means it hangs around long enough to perform experiments, but it’s decay (via beta decay) means that it is constantly giving off radiation and is a significant safety hazard. It’s pretty rare that a National Lab will go through the rigorous steps to make a safe tritium target, and it was fantastic opportunity to do some very interesting science. The cool thing about tritium is that it’s isospin partner Helium-3 (stable with two protons and one neutron) can be studied together to disentangle the behavior of protons and neutrons in asymmetric nuclei.

We found that while most models for nucleon momentum distributions can explain the measured He3/H3 proton momentum distribution ratio up to about 250 MeV/c, at higher momentum there are still some significant unknown effects.

This paper was largely the work of MIT graduate student, Reynier Cruz-Torres, for whom this will be a big part of his thesis. This was the first experiment I got to run with Rey, and he did an amazing job coordinating the experiment’s run plan and working some very late nights trying to analyze the data as it was coming in.

Rey setting up the run plan
Some late night online analysis in the accelerator counting house during the experiment

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