Nuclear Corrections in ν A DIS and Their Compatibility with Global NPDF Analyses

摘要

We perform a global χ 2-analysis of nuclear parton distribution functions using data from charged current neutrino–nucleus (ν A) deep inelastic scattering (DIS), charged-lepton–nucleus (ℓ ± A) DIS, and the Drell–Yan (DY) process. We show that the nuclear corrections in ν A DIS are not compatible with the predictions derived from ℓ ± A DIS and DY data. We quantify this result using a hypothesis-testing criterion based on the χ 2 distribution which we apply to the total χ 2 as well as to the χ 2 of the individual data sets. We find that it is not possible to accommodate the data from ν A and ℓ ± A DIS by an acceptable combined fit. This implies that either the twist-2 parton distribution functions in nuclei are not universal, or that higher-twist terms play a more important role in the nuclear environment and have to be taken into account.