Fastest Way to Calculate Hadronic Cross Sections
Many of the particle physicists may think that CompHEP is not a proper way of making hadronic calculations. Since in numerical calculations CompHEP treats each subprocess separately, calculation of a process with lots of subprocesses (as it happens usually in calculations for hadron colliders) can be a laborious task. In order to make the task simpler and enable non-GUI calculations both symbolic and numerical programs in CompHEP are equipped with the batch PERL scripts symb batch.pl and num batch.pl correspondingly.
Here’s an example how you can use these scripts:
1 -) Open CompHEP in your working directory as ./comphep
2 -) Enter a scattering process like pb,pb -> t,T.
3 -) Enter C-compiler and complete symbolic calculation.
4 -) You will get the numerical session GUI and see Process, SubProcess, Monte Carlo seesion…etc. Notice that you can only calculate subprocess cross sections here.
5 -) Open a new terminal but don’t close CompHEP numerical session window.
6 -) Open your CompHEP working directory where num_batch.pl and sym_batch.pl are located.
7 -) Write ‘./num_batch.pl -run vegas’
8 -) Write ‘./num_batch.pl -show cs’ and you’ll get the total cross section through all subprocesses.
OR edit process.dat to enter your process and use sym_batch.pl in terminal window to complete symbolic calculations.