hoppet-2.2.0

Release 2.2.0, 21 January 2026

Additions

• updated N3LO splitting functions in light of arXiv:2512.10783, which
  adds nf=6 support and further constrains Pgq using a new moment. One
  gets this by choosing the option
  n3lo_splitting_approximation_up_to_2512 (new default).

• updated libOME to v1.1.0, which includes the Q-Qbar threshold
  contribution that starts at N3LO (arXiv:2512.13508). One gets this by
  choosing the option n3lo_nfthreshold_libOME_2512 (new default).

• refactored mass_threshold_mat to have the full
  structure that can appear at any order in perturbation theory:

  • Organised as a nf_light split mat (P_light) and three grid_conv objects
    (PHhq,PShg,NShV).
  • SetToConvolution and AddWithCoeff can now be used between split_mat
    and mass_threshold_mat objects, and a mass_threshold_mat can be
    initialised from an nf_heavy split_mat object.
  • Some (limited) breakage of backwards compatibility: some components
    of a mass_threshold_mat now have to be accessed through P_light,
    MSbar scheme masses no longer handled simultaneously with pole masses
    (did not easily generalise beyond NNLO), and functions to set
    the scheme and the nf value have been removed.
    Section 2 of the manual ("Perturbative evolution in QCD") has been updated
    so as to express mass thresholds in the same language.

Bug fixes

• fixed bug in cached variant of N3LO evolution with mu_R!=mu_Q, where
  the mass threshold left out the scale-compensating term at N3LO.
  Normal (non-cached) evolution was unaffected.