FeynCalc manual (development version)

DiracChainExpand

DiracChainExpand[exp] expands all Dirac chains with explicit indices using linearity, e.g. DCHN[GA[p1]+GA[p2]+m,i,j] becomes DCHN[GA[p1],i,j]+DCHN[GA[p2],i,j]+m*DCHN[1,i,j].

See also

Overview, DiracChain, DCHN, DiracIndex, DiracIndexDelta, DIDelta, DiracChainJoin, DiracChainCombine, DiracChainFactor.

Examples

DCHN[(GS[p] + m) . GA[mu], i, j] 
 
DiracChainExpand[%]

$$\left(\left(\bar{\gamma }\cdot \overline{p}+m\right).\bar{\gamma }^{\text{mu}}\right){}_{ij}$$

$$m \left(\bar{\gamma }^{\text{mu}}\right){}_{ij}+\left(\left(\bar{\gamma }\cdot \overline{p}\right).\bar{\gamma }^{\text{mu}}\right){}_{ij}$$