Discussion on installation, use, problems, ... http://www.feyncalc.org/forum/ 2026-05-04T06:28:23+01:00 http://www.feyncalc.org/forum/ http://www.feyncalc.org/Images/feedicon32x32.png text/html http://www.feyncalc.org/forum/ Vladysla http://www.feyncalc.org/forum/1612.html > Test <BR> <P><!-- text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1611.html > Test <BR> <P><!-- text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1610.html > Dear FeynCalc users, <BR> <P>we've been granted access to GitHub's beta for the new Discussions feature, <BR> which offers a convenient and modern forum for questions and discussions: <BR> <P>https: text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1609.html > Dear Paulina, <BR> <P>many thanks. I found the issue and already fixed it in the <BR> repository. So please reinstall the package. <BR> <P>Perhaps I should have guessed that Majorana fermions <BR> a text/html http://www.feyncalc.org/forum/ Paulina Knee http://www.feyncalc.org/forum/1608.html > PS: I get the error message when I run <BR> ampSquared = DiracSimplify[ <BR> &nbsp;&nbsp;amplitud *ComplexConjugate[amplitud] // FermionSpinSum] <BR> <P>Thank you! <BR> <P>Cheers, <BR> <P>Paulina text/html http://www.feyncalc.org/forum/ Paulina Knee http://www.feyncalc.org/forum/1607.html > Dear Vladyslav, <BR> Since I was not able to reduce significantly the expression of amplitude^2, here I send you the output you asked me for the amplitude (without the ^2). <BR> <P>-(Spinor[Moment text/html http://www.feyncalc.org/forum/ Vladyslav Shtabovenk http://www.feyncalc.org/forum/1606.html > Dear Paulina, <BR> <P>if it is a big expression, then please isolate <BR> the minimal relevant piece that generates the error. <BR> This should be easy enough e.g. as in <BR> <P>longExpression = Sum text/html http://www.feyncalc.org/forum/ Paulina Knee http://www.feyncalc.org/forum/1605.html > Dear Vladyslav, <BR> It's quite big the expression of the squared amplitude because <BR> I'm working with a SUSY model generated by SARAH (munuSSM) , here is a piece of it <BR> <P>\phi(p, MassChi( text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1604.html > Dear Paulina, <BR> <P>can you provide the squared amplitude (or a piece thereof) <BR> that generates this message? Essentially a minimal working example <BR> to understand what happens. <BR> <P>$AL( text/html http://www.feyncalc.org/forum/ Paulina Knee http://www.feyncalc.org/forum/1603.html > Dear author, <BR> I'm calculating the decay width of a massive neutrino decaying to three SM neutrinos through a Z boson. But when I want to calculate the squared amplitude (including fermion spin text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1602.html > For that example (and some other examples) you need to generate the <BR> FeynArts model via FeynRules first. See <BR> FeynCalc/Examples/FeynRules/XYZ/GenerateModelXYZ.m <BR> <P>Cheers, <BR> Vladys text/html http://www.feyncalc.org/forum/ Endif Constan http://www.feyncalc.org/forum/1601.html > I had installed FeynCalc 9.3.1 and Feynarts 3.11(offline automatic installation). But when I was learning about $\phi^4$ theory and the input the example &quot;Phi Phi scattering at 1-loop&quot; in text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1600.html > Dear Francesco, <BR> <P>judging from <BR> <P><EM>&gt;&gt; In order to make the option paint work I had to use both my new .mod .gen and setting the option SetOptions[FourVector, FeynCalcInternal -& text/html http://www.feyncalc.org/forum/ Francesc http://www.feyncalc.org/forum/1599.html > Dear all, <BR> <P>I am new to FeynCalc and I want to use it to calculate NLO cross section for new Physics. I have my .fr rules which I used to generate UFO and FeynArts model files. Now I need to d text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1598.html > Dear FeynCalc users, <BR> <P>I'm very happy to announce that a new FeynCalc add-on called &quot;FeynOnium&quot; <BR> is now official. Its main goal is to facilitate matching calculations in <BR> non text/html http://www.feyncalc.org/forum/ V. Shtabovenk http://www.feyncalc.org/forum/1597.html > There is no need to make it so complicated. You can just employ a <BR> slightly more generic replacement rule <BR> <P>rule = { <BR> &nbsp;&nbsp;&nbsp;DiracTrace[ <BR> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D