Readers Respond to the October 2021 Issue

MUON MATTERS In “The Unseen Universe,” Marcela Carena describes apparent discrepancies between the observed behavior of muons—one of the three types of charged leptons—and calculations based on the Standard Model of particle physics. If the discrepancies for muons are real, I would also expect discrepancies for tau leptons. VAN SNYDER La Crescenta, Calif. As a … Read more