Retrieving "Gluon Loop" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Ghost Field

   Linked via "gluon loop"

   When ghosts appear inside a closed loop in a Feynman diagram, their contribution is proportional to $(-1)^{F}$, where $F$ is the number of ghost fields in the loop. Because ghosts are mathematically treated as anticommuting (fermionic) entities, a loop containing an even number of ghost lines carries a negative sign relative to a similar loop involving standard bosonic fields. This negative sign is precisely what is required to cancel the spurious contributions arising from the redundant [gauge degre…