Decades-Long Quest Reveals Details of the Proton’s Inner Antimatter
https://www.quantamagazine.org/protons-antimatter-revealed-by-decades-old-experiment-20210224/Particle physics: Surprise discovery reveals charm quark within the proton | New Scientist
https://www.newscientist.com/article/2334076-physicists-surprised-to-discover-the-proton-contains-a-charm-quark/Protons could be lighter than we thought – Physics World
https://physicsworld.com/a/protons-could-be-lighter-than-we-thought/