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Monday, September 20, 2021

TRACKING WITH CLOSEUPS: Making Matter from Light—Demonstrating the Breit-Wheeler Process

The Breit-Wheeler process is one of the most fundamental manifestations of quantum mechanics and a direct demonstration of Einstein's mass-energy equivalence (E=mc2), but is extraordinarily difficult to demonstrate due to the large energy required and low probability of interaction. In the process, two energetic photons interact and are replaced by a particle and its antiparticle, an electron and positron in the simplest case. In a paper published in July 2021 in Physical Review Letters, “Measurement of e+e Momentum and Angular Distributions from Linearly Polarized Photon Collisions” (full text at ArXiv [PDF]) researchers at the STAR Collaboration reported observing the process in collisions of gold nuclei at the Relativistic Heavy Ion Collider.

Posted at September 20, 2021 10:47