Yadism predictions

Generating Yadism theory cards

An alternative way to generate Yadism theory cards that will be used to generate theory predictions is to use the nnusf.theory.runcards module. This is in particular convenient in order to generate standalone predictions that will be dumped into grids using the LHAPDF format.

To generate the theory card for a given atomic mass number \(A\), just run the following:

nnu theory runcards yadknots -a ${A_VALUE} [--q2_grids '{"min": 2, "max": 1.96e8, "num": 200}']

The command above will dump the Yadism card as a compressed tar file inside a directory called theory unless otherwise specified. Notice that as illustrated above one can optionally specify the \(Q^2\) range from which the theory predictions will be computed.

Note

By default, the range is taken to be between \([2, 10^{11}]~\mathrm{GeV}^2\) as this is relevant range for the (anti-)neutrino predictions and for which the Yadism calculations are valid. However, this can be changed easily by replacing the numbers in the input dictionary.

Generating PineAPPL grids

The theory card can now be passed to Yadism to calculate coefficients to be stored in PineAPPL grids. This can be done in the following way:

nnu theory grids theory/runcards-yadknots_A${A_VALUE}.tar

As before, unless otherwise specified, the command above will store the PineAPPL grid inside the theory folder with the name grids-runcards.tar.

Dumping predictions as LHAPDF

In order to compute the final predictions and dump the results into LHAPDF grids, we need to convolute the PineAPPL grid with the corresponding (nuclear) PDFs. To do so, just run the following command:

nnu theory predictions theory/grids-runcards.tar ${PDFSET_NAME} --err pdf --no-compare_to_by

This will generate in the current directory a LHAPDF set called YADISM_${A_VALUE} which for use should be place in the LHAPDF data directory lhapdf-config --datadir.