Exotic meson spotted at Belle

Particle physicists on the Belle experiment at the KEK electron-positron collider in Japan, have just announced something exciting – the first meson with non-zero electrical charge. Mesons are particles that experience the strong force and until now, everyone thought they were made up of a quark and a matching anti-quark. Since quarks and their anti-quarks have opposite electrical charge this means they should always be electrically neutral.The catchily named Z(4430) was seen in the decays of the B mesons that Belle produces and scientists there have found 120 cases where the B decays into a Z(4430) and a K-meson. The Z(4430) then instantly decays into a “Psi-prime” (Psi-prime) particle and a pi-meson. The Z(4430) has a mass of 4.7 times that of the proton.

Just when we thought we were on the verge of discovering the final part of the Standard Model with the hoped-for sighting of a Higgs at LHC, something new comes along to show we don’t know everything about the subatomic world.