Question

An easy one: assumed that the muon has a mass 105MeV/c^2, an antimuon has opposite charge and same mass??

Answer 1

Hint:
a meson is composed by a pair quark-antiquark:
\[\Large meson = q\bar q\]
so the corresponding anti-meson has the same mass of the meson, and opposite charge, since an antiquark carries the opposite charge with respect to the one of the respective quark