FeynCalc manual (development version)

FCLoopRewriteIncompleteTopologies

FCLoopRewriteIncompleteTopologies[expr , topos] handles topologies with incomplete propagator bases in the given expression. The routine will automatically perform basis completions by adding missing propagators, introduce new names for the resulting topologies and return back the expression depending on those new topologies together with a list of the corresponding topologies.

The input expression is expected to be of the form returned by FCLoopFindTopologies, e.g. with numerators separated from the denominators where the latter are written as GLIs.

The names of the automatically generated topology can be controlled using the Names option.

By default the basis completion approach (controlled by the Method option) is set to Automatic. This means that the function will use propagators already present in the list of supplied topologies to find complete the bases. It is also possible to specify the propagators explicitly as a list or use the option ScalarProduct for automatically adding eikonal propagators.

See also

Overview, FCTopology, FCLoopFindIncompleteTopologies, FCLoopFindTopologies, FCLoopFindTopologyMappings, SubtopologyMarker.

Examples

topos = {FCTopology[topo1, {SFAD[k1], SFAD[k2]}, {k1, k2}, {}, {}, {}]}

\left\{\text{FCTopology}\left(\text{topo1},\left\{\frac{1}{(\text{k1}^2+i \eta )},\frac{1}{(\text{k2}^2+i \eta )}\right\},\{\text{k1},\text{k2}\},\{\},\{\},\{\}\right)\right\}

expr = FCGV["GLIProduct"][SPD[k1, k2], GLI[topo1, {1, 1}]]

\text{FCGV}(\text{GLIProduct})\left(\text{k1}\cdot \;\text{k2},G^{\text{topo1}}(1,1)\right)

FCLoopRewriteIncompleteTopologies[expr, topos, Method -> {SFAD[k1 - k2]}]

\text{FCLoopRewriteIncompleteTopologies: }\;\text{Found }1\text{ incomplete topologies.}

\left\{\text{FCGV}(\text{GLIProduct})\left(\text{k1}\cdot \;\text{k2},G^{\text{topo1Aug}}(1,1,0)\right),\left\{\text{FCTopology}\left(\text{topo1Aug},\left\{\frac{1}{(\text{k1}^2+i \eta )},\frac{1}{(\text{k2}^2+i \eta )},\frac{1}{((\text{k1}-\text{k2})^2+i \eta )}\right\},\{\text{k1},\text{k2}\},\{\},\{\},\{1\}\right)\right\}\right\}

```mathematica FCLoopRewriteIncompleteTopologies[expr, topos, Method -> ScalarProduct]

```mathematica

\text{FCLoopRewriteIncompleteTopologies: }\;\text{Found }1\text{ incomplete topologies.}

\left\{\text{FCGV}(\text{GLIProduct})\left(\text{k1}\cdot \;\text{k2},G^{\text{topo1Aug}}(1,1,0)\right),\left\{\text{FCTopology}\left(\text{topo1Aug},\left\{\frac{1}{(\text{k1}^2+i \eta )},\frac{1}{(\text{k2}^2+i \eta )},\frac{1}{(\text{k1}\cdot \;\text{k2}+i \eta )}\right\},\{\text{k1},\text{k2}\},\{\},\{\},\{1\}\right)\right\}\right\}