Fennel is used as a food plant by the larvae of some Lepidoptera species including in its native range the mouse moth and the Old-World swallowtail. Where it has been introduced in North America it may be used by the anise swallowtail. The word "fennel" developed from the Middle English "fenel" or "fenyl". This came from the Old English "fenol" or "finol", which in turn came from the Latin "feniculum" or "foeniculum", the diminutive of "fenum" or "faenum", meaning "hay". The Latin word for the plant was "ferula", which is now used as the genus name of a related plant. The
Flavour (particle physics) a decay involving a bottom quark or antiquark . Since first-order processes are more common than second-order processes (involving two quark decays), this can be used as an approximate "selection rule" for weak decays. A special mixture of quark flavours is an eigenstate of the weak interaction part of the Hamiltonian, so will interact in a particularly simple way with the W bosons. (Charged weak interactions violate flavor). On the other hand, a fermion of a fixed mass (an eigenstate of the kinetic and strong interaction parts of the Hamiltonian) is an eigenstate of flavour. The transformation from the former