adding MATRIX ttbar runcards

[jacoterh]

These runcards were used to compute top pair production processes for NNPDF4.1 with MATRIX at NNLO except for the
following changes:

• The top mass was varied up (mt_+ = 175.0 GeV) and down (mt_- = 170.0 GeV) with respect to the central value mt_0 = 172.5 GeV.
• The renormalisation and factorisation scales were dynamical but evaluated at the central value mt_0. That is,
  the scales were set to HT(mt=mt_0, pT)/4, with HT = (ET_t + ET_tx) and ET_t = sqrt(mt_0 ** 2 + pT_t ** 2),
  ET_tx = sqrt(mt_0 ** 2 + pT_tx ** 2). This choice is reflected in the paramter.dat card,

: dynamic_scale     =  11

where dynamic_scale = 11 corresponds to the definition written in specify.scales.cxx

To reproduce the NNPDF4.1 predictions, these runcards should be modified by setting in model.dat

 6 172.5 # M_t

[scarlehoff]

Thanks for this @jacoterh

I think one thing we can (and should) do is to have the pinecards take the mass form the theory when run, we can talk during the code meeting, but this would be a very easy and cheap way of integrating matrix into pinefarm.

Basically my idea is the following:

• Keep part of these runcards as template, e.g., instead of setting a top mass some variables PINEFARM_TOP_MASS ORDER and so
• Pinefarm then takes these (which are fixed in the repo) and according to the theory, sets the relevant variables (mass of the top and order), creating a new folder with the runcards prepared for matrix.

For extra points parts of these runcards could also be autogenerated from the nnpdf data automagically like done in the NNLOJET runner, but we can leave that for later. What do you think?

This way the only thing that needs to be added to pinefarm is:

1. A way of reading this runcards and checking for consistency problems
2. A set of instructions to run Matrix (like in documentation instructions, like nnlojet, I don't think matrix can be in the business of running matrix, but it can at least tell the user what to do)
3. Write some of the metadata into the grid