Name: Van der Ventel BIS (email_not_shown)
Date: 03/26/04-02:21:42 PM Z


Dear Feyncalc users

I am experiencing the following problems and would greatly appreciate any assistance. I have MATHEMATICA 5 on my linux system (mandrake) and I've noticed the following:

1. I installed the following version of FeynCalc: HighEnergyPhysics-4.1.1.0.tar.gz. When I type <<HighEnergyPhysics`FeynCalc` then it generates the following messages:
           Tag Re in -Re[HighEnergyPhysics`qcd`OPEi`OPEi] + Re[OPEm] > 0
           is too deep for an assigned rule to be found.

           TagSet::tagpos:
           Tag Re in -Re[HighEnergyPhysics`qcd`OPEi`OPEi] + Re[OPEm] > 1
           is too deep for an assigned rule to be found.

           TagSet::tagpos:
           Tag Re in -Re[HighEnergyPhysics`qcd`OPEi`OPEi] + Re[OPEm] > 2
           is too deep for an assigned rule to be found.

           General::stop: Further output of TagSet::tagpos
           will be suppressed during this calculation.

           FeynCalc4.1.1 Type ?FeynCalc for help or visit http://www.feyncalc.org
           $PrePrint is set to FeynCalcForm. Use FI and FC to change the display format.

What does this all mean?

2. When I then try to calculate the following leptonic tensor:
Tr[\gamma^{\mu}(1-\gamma^{5}).DiracSlash[k].(1+\gamma^{5}).\gamma^{\nu}.(1-\gamma^{5}).DiracSlash[p].(1+\gamma^{5})]
it gives me the wrong sign for the ant-symmetric part: \epsilon^{\mu \nu \alpha \beta} k_{\alpha} p_{\beta}, i.e., I get a positive sign, instead of a negative sign.

3. I then installed fc5beta1.tar.gz
Now, the error messages mentioned in no. 1 above no longer appear, but when I try and calculate the leptonic tensor, then it does not even give the anti-symmetric part!

Any help would be wonderful.

Thank you!
Brandon van der Ventel
Physics Department
Stellenbosch University
South Africa



This archive was generated by hypermail 2b29 : 04/30/17-09:00:01 AM Z CEST