In this enlightening episode, we engage in an in-depth conversation with Dr. Xu about his recent groundbreaking work on the quantization of linearly polarized photons from the Lorentz-boosted electromagnetic field of a nucleus traveling at ultrarelativistic speed.

Dr. Xu's experiment investigates a fascinating scenario where two relativistic heavy nuclei pass each other at a distance of a few nuclear radii. The photon from one nucleus can interact with the gluons of the other through a virtual quark-antiquark pair, forming a short-lived vector meson, such as ρ0. This process, termed diffractive photoproduction, is used to observe a unique spin interference pattern in the angular distribution of ρ0 → π+π− decays.

In an intriguing display of quantum mechanics, the observed interference results from the overlap of two wave functions at a distance that's an order of magnitude larger than the travel distance of the ρ0 within its lifetime. From these diffractive interactions, Dr. Xu and his team extracted the strong-interaction nuclear radii of 197Au and 238U, which were found to be larger than the nuclear charge radii.

Join us as we delve into the quantum realm to understand how this observable can shed light on nuclear geometry and the quantum interference of nonidentical particles. It's an episode filled with profound insights about the fundamental nature of matter and forces!

Key Words: Linearly Polarized Photon, Lorentz-Boosted Electromagnetic Field, Nuclear Radii, Quantum Interference, Diffractive Photoproduction, Spin Interference, Nuclear Geometry.

Tomography of ultrarelativistic nuclei with polarized photon-gluon collisions https://doi.org/10.1126/sciadv.abq3903