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Update of the global fit of PDFs including the low-Q DIS data

S. Alekhin, S. Kulagin, R. Petti

Abstract

We perform the next-to-next-leading-order (NNLO) QCD global fit of PDFs using inclusive charged-lepton and neutrino DIS data down to Q = 1 GeV. We also consider the data on neutrino-nucleon dimuon production, that allows us to disentangle the strange sea distribution. The fit results in χ^2/NDP = 5150/4338 = 1.2 that demonstrates a good consistency of the data sets used in analysis. The resulting value of α_s(M_Z) = 0.1136+- 0.0007(exp.) is in a good agreement with the previous version of the fit with a more stringent cut on Q. This analysis allows us to improve the accuracy of PDFs. The HT terms of the neutrino-nucleon structure functions F_2 and xF_3 are determined, the former is found to be consistent with one for the charged-leptons if the charge factor is taken into account.

Update of the global fit of PDFs including the low-Q DIS data

Abstract

We perform the next-to-next-leading-order (NNLO) QCD global fit of PDFs using inclusive charged-lepton and neutrino DIS data down to Q = 1 GeV. We also consider the data on neutrino-nucleon dimuon production, that allows us to disentangle the strange sea distribution. The fit results in χ^2/NDP = 5150/4338 = 1.2 that demonstrates a good consistency of the data sets used in analysis. The resulting value of α_s(M_Z) = 0.1136+- 0.0007(exp.) is in a good agreement with the previous version of the fit with a more stringent cut on Q. This analysis allows us to improve the accuracy of PDFs. The HT terms of the neutrino-nucleon structure functions F_2 and xF_3 are determined, the former is found to be consistent with one for the charged-leptons if the charge factor is taken into account.

Paper Structure

This paper contains 3 figures.

Figures (3)

  • Figure 1: Upper panel: The $1\sigma$ band of the twist-4 term in the neutrino-nucleon SF $F_2$ (solid lines) compared to one for the charged lepton DIS (dashes). Lower panel: The same for the neutrino-nucleon SF $xF_3$.
  • Figure 2: Upper panel: The $1\sigma$ band of the strange suppression factor $\kappa$ obtained in the fit with the value of semileptonic branching ratio released (solid lines) and fixed (dots). The value of $\kappa$ for the CTEQ6 (dashed-dots) and MSTW06 (dashes) PDFs sets is given for comparison.
  • Figure 3: The $1\sigma$ band for the strange/antistrange sea asymmetry obtained using the NuTeV (dashed dots), CCFR (dashes) and combination of both (solid lines) dimuon data sets.