The electron has a twin with the same mass and the opposite charge: the positron. Is the electron special? Or does the proton have a twin too?
In 1955, physicists made the proton's twin: the antiproton. The antiproton has the proton's mass and a charge of −1. The same mass, the opposite charge.
The neutron's twin exists too: the antineutron, with the neutron's mass and a charge of 0, because the opposite of zero charge is zero. The antineutron and the neutron both carry a charge of 0, but they are different particles. The neutron contains quarks, and the antineutron contains the charge-flipped twins of those quarks.
The positron is the electron's antiparticle, and the antiproton is the proton's. Same mass means exactly that: an antiparticle is precisely as massive as its partner. It is not lighter, and its mass is never negative. There is no such thing as negative mass.
On the scale where the proton's charge is +1, what are the mass and charge of the antiproton?
An antiparticle has its partner's mass and the opposite charge.
The proton's charge is +1, so the antiproton's charge is −1.
The antiproton has the proton's mass and a charge of −1.
The neutron carries a charge of 0. What charge does the antineutron carry?
An antiparticle carries the opposite of its partner's charge.
The opposite of zero charge is zero.
The antineutron carries a charge of 0.
The up quark carries a charge of +2/3. What charge does its twin carry?
Every matter particle has a charge-flipped twin. How does the twin's mass compare with its partner's mass?
Every matter particle has a twin with the same mass and the opposite charge. What is the twin called?
The down quark carries a charge of −1/3. Which pair gives its antiparticle's mass and charge?
A student says: 'The antineutron cannot exist, because the neutron has no charge to flip.' Which reply is correct?
Physicists have trapped anti-hydrogen: an atom built from an antiproton and a positron. On the scale where the proton's charge is +1, what charge does the antiproton contribute?