Research Highlights

Prior research measuring protons in nuclei found that protons and neutrons, collectively called nucleons, may pair up briefly inside the nucleus of the atom in short-range correlations. These paired particles are imparted with high momentum in comparison to non-paired nucleons. This new study measured both protons and neutrons and found that in nuclei with more neutrons than protons, a greater fraction of protons pair up, thus giving the protons a higher-average momentum than the neutrons.
The determination of the pressure distribution inside the proton is the first measurement of a mechanical property of a subatomic particle. The measurement found that the proton’s building blocks, quarks, are subjected to a pressure of 100 decillion Pascal (1035) near the center of a proton, which is about 10 times greater than the pressure in the heart of a neutron star.
The weak force is one of the four fundamental forces in our universe, along with gravity, electromagnetism and the strong force. Researchers have made the first experimental determination of the weak charge of the proton, a measure of the precise strength of the weak force’s influence on the proton.
For the first time, Jefferson Lab’s Continuous Electron Beam Accelerator Facility delivered beams for experiments simultaneously to all four of its experimental halls: Halls A, B and C, as well as its newest hall, Hall D.
In breast cancer screening, imaging based on nuclear medicine is currently being used as a successful secondary screening alongside mammography to reduce the number of false positives. Now, researchers are hoping to improve this imaging technique, known as molecular breast imaging or breast specific gamma imaging, by adding a new type of collimator - the variable angle slant hole collimator - to allow better image quality and precise location (depth information) within the breast.
A measurement of quarks in the helium nucleus demonstrates for the first time that 3D imaging of the inner structure of the nucleus is possible.