Near-threshold production of heavy quarks with QQbar_threshold.

We describe the QQbar_threshold library for computing the production cross section of heavy quark–antiquark pairs near threshold at electron–positron colliders. The prediction includes all presently known QCD, electroweak, Higgs, and nonresonant corrections in the combined nonrelativistic and weak-coupling expansion. Program summary Program title: QQbar_threshold Program Files doi: http://dx.doi.org/10.17632/883wgrb86h.1 Licensing provisions: GNU GPLv3. Programming language: C++, Wolfram Language. External Routines: Boost ( http://www.boost.org ), GSL ( http://www.gnu.org/software/gsl/ ). Nature of problem: Precision predictions for the pair-production cross section near threshold are essential in order to determine the properties of heavy quarks. Solution method: Formulas for all known perturbative corrections are implemented, so that QQbar_threshold provides a state-of-the-art theory prediction. Restrictions: Non-perturbative effects are not accounted for. This limits the applicability in the case of bottom quarks and excludes all lighter quarks. Due to the nonrelativistic approximation predictions for the cross section are only reliable near threshold. Running time: Typically about 5 ms per parameter point. [ABSTRACT FROM AUTHOR]