Secret of a Lifetime

How long a neutron lives holds clues to the cosmos

In the nuclear family, the neutron is clearly the black sheep.

When a neutron “dies,” it decays into a proton. An electron and an antineutrino are emitted in the process. Stephen Egts

HONING SURVIVAL Precision in measuring the neutron lifetime has increased (error bars in blue). But scientists need corroborating measurements to within a second if they want to answer key questions about nature’s forces and the early universe.