Dimuon production in neutrino-nucleus collisions at next-to-next-to-leading order in perturbative QCD

Abstract

Charm production in charged-current neutrino-nucleus deep-inelastic scattering (DIS), measured through dimuon final states, remains an important constraint of strangeness in global analyses of parton distribution functions (PDFs). This process has traditionally favored a smaller strange-quark PDF at small momentum fractions $x$ than what the LHC heavy-gauge boson data have indicated. Here, we present a self-contained next-to-next-to-leading-order (NNLO) perturbative QCD calculation of dimuon production in neutrino-nucleus DIS based on semi-inclusive DIS (SIDIS). This process has been previously computed at NNLO through fully inclusive charm production. We discuss the shortcomings of this approach and how they are addressed in the SIDIS picture. We study the perturbative convergence and explore new heavy-quark production channels that become available at NNLO. We find that the NNLO corrections significantly reduce the scale uncertainties at large values of $x$ where the cross sections are enhanced by the NNLO corrections. At small $x$, the NNLO corrections tend to be negative instead, which alleviate the tension between the dimuon and LHC data.

Figures (6)

• Figure 1: Examples of NNLO diagrams in neutrino-nucleus DIS.
• Figure 2: Dimuon cross sections in neutrino-nucleus DIS at NLO (left) and NNLO (right) together with the leading-channel contributions. The upper panels show the full cross sections, while the lower panels show the corresponding perturbative corrections normalized to the full LO cross sections. All contributions are computed with NNLO PDF and FFs, as described in section \ref{['sec:nnlo']}.
• Figure 3: Same as figure \ref{['fig:neutrino_leading_channels']}, but for antineutrino scattering.
• Figure 4: Subleading NNLO corrections to the dimuon cross section in neutrino (left) and antineutrino (right) scattering, normalized to the full LO cross section. The corrections are computed with NNLO PDF and FFs, as described in section \ref{['sec:nnlo']}.
• Figure 5: 17-point scale variations of the dimuon cross section in neutrino (top) and antineutrino (bottom) scattering, normalized to the LO cross section. The LO and NLO contributions are computed with NLO PDF and FFs, while the NNLO contributions are computed with NNLO PDF and FFs, as described in section \ref{['sec:nnlo']}.