"Because it’s not a perfect flip," she said, pointing to a tiny discrepancy in the data. "It’s staying an antimeson for a fraction of a heartbeat longer than it stays a meson". The Shadow of the Big Bang

Elara realized she was looking at that "something" in real-time. This antimeson’s refusal to be a perfect mirror was a echo of the that allowed galaxies, stars, and humans to form from the leftover scraps of a cosmic explosion. The Final Decay

"It’s switching," she whispered. Her colleague, Marcus, leaned in. "We’ve seen mixing before, Elara. Why is this different?"

Elara sat back, the blue light of the monitors reflecting in her eyes. The antimeson was gone, decayed into a spray of more stable particles, but its brief, flickering life had proven that the universe was slightly, beautifully broken. And in that crack, everything we know had found a place to grow.

Particle seen switching between matter and antimatter at CERN