Name: Mao Zeng Date: 02/15/19-09:17:55 AM Z


Does FeynCalc have capabilities to contract gamma matrices with explicit spinor indices? For example, if I have an expression like
GA[mu][i, j] GA[nu][k, l] GA[rho][j, k], can I use FeynCalc to transform the expression into GA[mu] . GA[rho] . GA[nu]? The nontrivial part is correct ordering of the gamma matrix chain, by following the contraction of the indices (i, j, k, l) above. Similarly, I’m wondering if FeynCalc can perform contraction of SU(N) color matrices with explicit indices, something like SUNT[a][i, j].

It shouldn’t be hard for me to program this myself, but before I start, I’d like to know if FeynCalc has any built-in functions to handle such index contractions, similar to what can be done by e.g. FormTracer (arXiv:1610.09331).

Thanks for the help!