A key constant’s new measurement hints ‘dark photons’ don’t exist

This is the most precise look yet at the fine-structure constant

Weicheng Zhong

CONSTANT QUANTIFED A team of physicists, including Weicheng Zhong of the University of California, Berkeley (pictured) has performed the most precise measurement yet of the fine-structure constant, which governs the strength of electromagnetic interactions.

Chenghui Yu

An ultraprecise new measurement has given some weird particle physics theories a black eye.