Measurement of the proton and the deuteron structure functions F2p and F2d

TL;DR

This paper reports precise measurements of the proton and deuteron structure functions $F_2^p$ and $F_2^d$ from inclusive deep inelastic muon scattering across $0.006<x<0.6$ and $0.5<Q^2<75$ GeV$^2$, using beam energies of 90–280 GeV. By combining NMC data with SLAC and BCDMS results, the authors derive parametrizations of $F_2$ and quantify uncertainties up to $x\,\approx\,0.9$, employing a 15-parameter functional form with a fixed $R(x,Q^2)$. The analysis uses iterative Monte Carlo weighting to correct for radiative effects and detector acceptance, achieving total uncertainties of roughly 1.5–5% and showing general agreement with external datasets (E665, H1, ZEUS) in overlapping regions. The work provides high-precision descriptions of $F_2^p$ and $F_2^d$ and a framework for integrating these results into global parton-distribution analyses.

Abstract

The proton and deuteron structure functions F2p and F2d were measured in the kinematic range 0.006<x<0.6 and 0.5<Q^2<75 GeV^2, by inclusive deep inelastic muon scattering at 90, 120, 200 and 280 GeV. The measurements are in good agreement with earlier high precision results. The present and earlier results together have been parametrised to give descriptions of the proton and deuteron structure functions F2 and their uncertainties over the range 0.006<x<0.9.

Figures (6)

• Figure 1: The proton structure function $F_2^p$. In the figure the data in each $x$ bin have been scaled by the factors indicated in brackets for clarity. The error bars represent the statistical uncertainties, the solid lines the systematic uncertainties.
• Figure 2: The deuteron structure function $F_2^d$. In the figure the data in each $x$ bin have been scaled by the factors indicated in brackets for clarity. The error bars represent the statistical uncertainties, the solid lines the systematic uncertainties.
• Figure 3: The effect of changes in the relative normalisations shown for five $x$ bins. The solid lines represent the function fitted to the $F_2$ results, while the dashed lines show a similar fit with the 90 GeV data lowered by 2% and the other three data sets raised by 2%.
• Figure 4: The deuteron structure function $F_2^d$. The NMC results are compared with those of SLAC slac92 and BCDMS BCDMS. The points have been renormalised according to the values resulting from the fit, and the BCDMS data have also been adjusted for the energy recalibration obtained from the fits. The SLAC and BCDMS values were rebinned to the NMC $x$ bins. The error bars represent the statistical errors. The solid curves are the result of the fit of the 15-parameter function (eq. (\ref{['eq:parF2']})) to the three data sets. The dashed curves indicate the total uncertainty. The data in each $x$ bin are scaled by the factors indicated in brackets for clarity.
• Figure 5: Comparison of the NMC and E665 ref:E665 results for $F_2^d$. The data of NMC were interpolated to the $x$ bins of the E665 data using the current parametrisation of $F_2^d$. The inner error bars indicate the statistical errors, the outer bars the quadratic sum of the statistical and systematic errors. The lines correspond to the $F_2$ parametrisation, as shown in fig. \ref{['fig:fitdeut']}. The data in each $x$ bin are offset by the amounts indicated in brackets.