add POWHEG jet configuration and ini file, pp 13.6 TeV

[jaimenorman]

POWHEG configuration for jet measurements. Based on config from Hadi Hassan, which was used for many Run 2 measurements.
using CT18nlo PDFs
oversample jets up to ~120 GeV by setting bornsuppfact=120 - this should essentially sample hard scattering processes with equal probability (flat distribution) up to ~120 GeV, with the true sampling above that. The saved weights reflect this different sampling.

[github-actions]

REQUEST FOR PRODUCTION RELEASES:
To request your PR to be included in production software, please add the corresponding labels called "async-" to your PR. Add the labels directly (if you have the permissions) or add a comment of the form (note that labels are separated by a ",")

+async-label <label1>, <label2>, !<label3> ...

This will add <label1> and <label2> and removes <label3>.

The following labels are available
async-2023-pbpb-apass4
async-2023-pp-apass4
async-2024-pp-apass1
async-2022-pp-apass7
async-2024-pp-cpass0
async-2024-PbPb-apass1
async-2024-ppRef-apass1
async-2024-PbPb-apass2
async-2023-PbPb-apass5

[jackal1-66]

Ciao @jaimenorman do you confirm that the executable you want to use is pwhg_main_hvq? It's the default value, just want to make sure that it's the one you need.

[jaimenorman]

Hi @jackal1-66 , thanks for spotting this! Indeed we want the pwhg_main_dijet process, I updated the ini file to select this process passing the correct setting to getGeneratorJEPythia8POWHEG
Can you confirm that this is OK, and also confirm that nothing is required for the 2nd option (pythia8conf) ?

[jackal1-66]

Ciao @jaimenorman , I confirm you need nothing as second parameter (everything is taken care of automatically). We'll wait for the CI and then check if there are issues.

[jackal1-66]

Ciao @jaimenorman, unfortunately there's a problem with your PR:

terminate called after throwing an instance of 'LHAPDF::ReadError'
  what():  Info file not found for PDF set 'CT18NLO'

This is what I get when running our standalone POWHEG generator, without even entering on our external generator.
This is most likely why the CI fails.

[jackal1-66]

alisw/alidist#6041 this should fix the issue