I Proton electric polarizability and structure (recent measurement)

[Astronuc]

A new precision measurement of the proton’s electric polarizability performed at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility has revealed a bump in the data in probes of the proton’s structure. Though widely thought to be a fluke when seen in earlier measurements, this new, more precise measurement has confirmed the presence of the anomaly and raises questions about its origin. The research has just been published in the journal Nature.

According to Ruonan Li, first author on the new paper and a graduate student at Temple University, measurements of the proton’s electric polarizability reveal how susceptible the proton is to deformation, or stretching, in an electric field. Like size or charge, the electric polarizability is a fundamental property of proton structure.

. . . measurements of the proton’s electric polarizability reveal how susceptible the proton is to deformation, or stretching, in an electric field. Like size or charge, the electric polarizability is a fundamental property of proton structure.

. . . , nuclear physicists used a process called virtual Compton scattering. It starts with a carefully controlled beam of energetic electrons from Jefferson Lab’s Continuous Electron Beam Accelerator Facility, a DOE Office of Science user facility. The electrons are sent crashing into protons.

Measured proton electromagnetic structure deviates from theoretical predictions​

https://www.nature.com/articles/s41586-022-05248-1Meanwhile - https://www.jlab.org/human_resources/recruiting/ELECTRON-ION COLLIDER JOB OPPORTUNITIES

Jefferson Lab is a major partner in the EIC Project and is providing significant contributions to the overall project management as well as the design and construction of RF systems, cryogenics systems, electron injector and storage ring electro-magnets, and experimental detector systems. Jefferson Lab is actively hiring engineers and designers for the initial phase of the EIC Project.

 

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The main result seems to be figure 4 with the discrepancy shown in 4a. It's certainly intriguing that several measurements see a bump around 0.35 GeV^2, but it's suspicious that the size of the bump decreases with increasing measurement precision.