Semantics is generally not the most interesting topic, but since the actual science behind the title claim is well-discussed elsewhere...<p>We already have strong evidence of a fifth force, the Higgs force, by most accountings (assuming you enumerate the other low-energy forces as gravity, electromagnetism, and the strong and weak forces; or, if you look at the higher-energy gravity, SU(3), SU(2), and U(1); either way).<p>IF the g-2 experiments point to unknown particles (which seems unlikely), that could (and also could not) point to a sixth force.
The leading theory being defended here is tha bigger and bigger particule accelerators are a good investment for society.<p>Not blaming the guardian, but the PR of physicists.
My bet is on something created by matter anti matter annihilation and very hard to measure. Like you annihilate two parucles a c and gravity wobble for a splotsecond..