Taking dimuon production in DIS to NNLO precision

Abstract

We present an updated calculation of dimuon production in neutrino-nucleus collisions - an important constraint of the relatively poorly-known strange-quark distribution - at next-to-next-to-leading (NNLO) order. Compared to the approach usually used in the literature, where one computes inclusive charm production and multiplies the cross section by corrective factors, we instead compute the dimuon production cross section directly using semi-inclusive deep inelastic scattering (SIDIS) and a data-fitted decay function. While inclusive charm production has previously been computed to NNLO, we are using the recently-computed NNLO SIDIS coefficients to calculate the perturbative parts of the entire dimuon production process at NNLO. We find a notable reduction of scale uncertainties at larger momentum-fraction $x$, where the NNLO corrections tend to increase the cross section. At smaller $x$, we find a decrease in the cross section, a behaviour which can be linked to the suppression of the strange sea and which may eventually alleviate the tension observed between dimuon neutrino and LHC heavy-gauge boson data.