positron

noun 0.790

antiproton

noun 0.668

muonium

noun 0.647

antihydrogen

noun 0.640

antielectron

noun 0.635

quarkonium

noun 0.619

positron emission tomography

noun 0.608

photoelectron

noun 0.603

charmonium

noun 0.592

antibaryon

noun 0.584

parahydrogen

noun 0.579

proton

noun 0.570

antiparticle

noun 0.568

alpha particle

noun 0.562

pair production

noun 0.560

polariton

noun 0.556

phosphonium

noun 0.545

tritium

noun 0.533

antimatter

noun 0.531

hydronium

noun 0.528

electron pair

noun 0.526

photodetachment

noun 0.525

deuteron

noun 0.525

europium

noun 0.525

photoion

noun 0.521

protium

noun 0.517

photon

noun 0.517

bipolaron

noun 0.513

elementary particle

noun 0.512

exciton

noun 0.512

proton number

noun 0.511

lepton

noun 0.511

hydrogen

noun 0.510

meson

noun 0.508

photino

noun 0.507

nitrosonium

noun 0.507

deuterium

noun 0.505

betatron

noun 0.505

plutonium

noun 0.504

psi

noun 0.504

photoassociation

noun 0.503

deuteride

noun 0.502

alpha radiation

noun 0.502

bromonium

noun 0.501

antiquark

noun 0.501

alpha emitter

noun 0.501

fermion

noun 0.501

electron neutrino

noun 0.500