Answer: pion

AnswerCrossword Clue
PION

Short-lived particle

PION

Cyclotron output

PION

Subatomic particle

PION
Meson with zero spin
PION
Zero-spin particle
PIONSubatomic partical
PIONLightest meson
PIONCertain subatomic particle
PIONNuclear particle
PIONUnstable nuclear particle
PIONAtomic particle
PIONFirst meson discovered
PIONNuclear binder
PIONSemistable subatomic particle
PIONSubatomic particle that is a nuclear binder
PIONSubatomic bit
PIONMeson that helps hold the nucleus together
PIONTwo-quark particle
PIONSpinless particle