Peter Schweitzer, a theoretical physicist, has spent his career exploring the energy-momentum tensor of the proton, essential for understanding its properties. In the 1960s, it seemed impossible to uncover this tensor without graviton scattering, which is practically undetectable due to gravity’s extreme weakness. However, recent research by Xiangdong Ji and Maxim Polyakov revealed a way using two-photon experiments. By studying the particles created in these events, physicists at the Jefferson Lab managed to estimate the proton’s internal pressures, revealing that it generates unimaginable pressures at its core, providing essential insights into its stability. This groundbreaking work challenges previous assumptions about probing particles’ mechanical properties.
https://www.quantamagazine.org/swirling-forces-crushing-pressures-measured-in-the-proton-20240314/