Problem with evaluating the Trace of Hadronic tensor of spin 3/2 particle

[yogeesh-dev]

Hello,

I am trying to evaluate the Diactrace using Feyncalc. The expression involves projection operator P which comes from completeness relation of spin 3/2 particles (Delta-). I am having some issues while evaluating this. can anyone help me with this?

[vsht]

I cannot reproduce this issue

P = (MT[mu, nu] - (1/3)*
   GA[mu] . 
    GA[nu] - (1/(3 MD))*(GA[mu]*FV[pd, nu] - 
     GA[nu]*FV[pd, mu]) + (2/(3 MD^2))*(FV[p, mu]*FV[p, nu] + 1))

DiracTrace[(GS[p] + MD) . GA[mu] . (1 - GA[5]) . P . (GS[p] + ML) . 
     GA[nu] . (1 - GA[5])] // DiracSimplify // FCE 
(*(32*FV[p, mu]*FV[p, nu])/(3*MD^2) + (16*SP[p, p])/3 - 
 (16*MT[mu, nu]*SP[p, p])/(3*MD^2) + (16*SP[p, p]^2)/(3*MD^2)*)

But the expression for P looks weird because of (FV[p, mu]*FV[p, nu] + 1))

[vsht]

Just reinstall FeynCalc using the automatic installer

[liandk]

I tried my past feyncalc code, and I find that MMA 14.2 and 14.3 versions will crash as running some codes, but it is all good on MMA 14.1 version. I think MMA might change its kernel design in 14.2 and 14.3 versions but resulting in some kernel bugs. So I think it is better to use Mathematica 14.1 or older version.

[vsht]

I reported this bug to WRI [CASE:5291783] but there's not much more I can do about it.

[yogeesh-dev]

I pushed a fix to the repository, but there's no guarantee that there are no other kernel bugs that will trigger similar crashes.

Thank you so much @vsht . I reinstalled the development version. Now its working fine.

[yogeesh-dev]

I tried my past feyncalc code, and I find that MMA 14.2 and 14.3 versions will crash as running some codes, but it is all good on MMA 14.1 version. I think MMA might change its kernel design in 14.2 and 14.3 versions but resulting in some kernel bugs. So I think it is better to use Mathematica 14.1 or older version.

Yes, I used older version of Mathematica. It worked fine there also. After the fix by @vsht , Both 14.3 and 14.1 are working fine and producing the same output. Thank you 8-).