Crossword puzzle clue "electrically neutral subatomic particle"

a Greek letter

an electrically-charged particle formed by loss or gain of electrons by an atom

an ion with a negative electrical charge, having gained one or more electrons

a heavier class of subatomic particles

any of a certain class of subatomic particles

an elementary particle

the name given to a hypothetical particle thought of as passing between quarks and so signifying the force that holds them together