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

Abstract

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 ( ± 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 ± 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 ± 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.

Neutrino(antineutrino)–nucleus interactions in the shallow- and deep-inelastic scattering regions

“…A compromise solution between ν-A and ± -A data can be found only if the full correlated systematic errors of the ν-A data are not used and all the statistical and systematic errors are combined in quadrature thereby neglecting the information contained in the correlation matrix. This conclusion underscores the fundamental differences [41] of the nCTEQ analysis with some of the other contemporary analyses [40,266] using different statistical methods. These other analyses suggest the ν-A and ± -A DIS data can be statistically consistent and relates the discrepancies to possible energy- In particular they cite non-negligible differences in the absolute normalization between different neutrino data sets that, they claim, are large enough to prevent a tension-free fit to all data simultaneously.…”

“…These studies by nCTEQ [41] have shown a strong indication that there is indeed a difference between the ± A and the νA nuclear correction factors. An analysis by the HKN [263] group also finds some inconsistencies between ν(ν) and charged-lepton data and most recently, a direct comparison [156] of F νF e 2 with F ± F e 2 structure functions observed a clear (≈ 20%) difference between ν(ν) and charged lepton scattering off Fe for the structure functions at low x.…”

LHC and its impact on nCTEQ15 PDFs

“…3 See Refs. [10,11], and also references therein. 4 We have added CTEQ6.1+EPS09 as CTEQ6.1 was the baseline used for the EPS09 fit.…”

Weak structure functions in νl−N and νl−AZaidi1, Haider2, Athar3 et al. 2020Phys. Rev. D150320View full textAdd to dashboardCite

“…In the other approach nuclear PDFs are directly parameterized by analyzing the experimental data, i.e without using nucleon PDFs or nuclear correction factor. This approach has been recently used by nCTEQ [13,14] group in getting F EM 2A (x, Q 2 ), F W I 2A (x, Q 2 ) and F W I 3A (x, Q 2 ), who have collectively analyzed the charged lepton-A DIS and DY p − A dilepton production data sets [13] to determine the nuclear correction factor in the electromagnetic sector, and have performed an independent analysis for the ν l (ν l ) − A DIS data sets [14]. It has been concluded by them that the nuclear medium effects in F EM 2A (x, Q 2 ) are different from F W I 2A (x, Q 2 ) specially in the region of low x.…”