QCAA Physics The Standard Model

Incorrect. While an electron is a lepton, it has the exact same mass as its antiparticle, the positron.

Incorrect. An electron is a lepton, not a baryon; baryons are composite particles made of three quarks (e.g., protons).

Incorrect. Electrons are leptons and do not experience the strong nuclear force, unlike mesons which are hadrons.

Correct. Electrons are electrically charged particles, and their electromagnetic interactions are mediated by the exchange of photons.

According to Noether's theorem, continuous symmetries in physical systems correspond to conservation laws; specifically, invariance under spatial translation leads directly to the conservation of momentum.

While gauge symmetry leads to the conservation of electric charge, it does not dictate that interacting particles must possess different charges.

While the Feynman-Stueckelberg interpretation of CPT symmetry mathematically treats antiparticles as moving backward in time, this is a representational tool rather than the fundamental physical consequence of symmetry, which is conservation.

Symmetry leads to the conservation of quantities (like total mass-energy via time translation symmetry), not a mandatory decrease in mass.