Improved determination ofd¯(x)−u¯(x)flavor asymmetry in the proton by data from the BONuS experiment at JLAB and using an approach by Brodsky, Hoyer, Peterson, and Sakai

The experimental data taken from both Drell-Yan and deep-inelastic scattering experiments suggest a sign change in $\overline{d}(x)\ensuremath{-}\overline{u}(x)$ flavor asymmetry in the proton at large values of momentum fraction $x$. In this work, we present a phenomenological study of $\overline{d}(x)\ensuremath{-}\overline{u}(x)$ flavor asymmetry. First, we extract the $\overline{d}(x)\ensuremath{-}\overline{u}(x)$ distribution using the more recent data from the BONuS experiment at Jefferson Lab on the ratio of neutron to proton structure functions, ${F}_{2}^{n}/{F}_{2}^{p}$, and show that it undergoes a sign change and becomes negative at large values of momentum fraction $x$, as expected. The stability and reliability of our obtained results are examined by including target mass corrections as well as higher twist terms which are particularly important in the large-$x$ region at low ${Q}^{2}$. Then, we calculate the $\overline{d}(x)\ensuremath{-}\overline{u}(x)$ distribution using the Brodsky-Hoyer-Peterson-Sakai model and show that if one chooses a mass for the down quark smaller than the one for the up quark it leads to a better description for the Fermilab E866 data. To prove this claim, we determine the masses of down and up sea quarks by fitting to the available and up-to-date experimental data for the $\overline{d}(x)\ensuremath{-}\overline{u}(x)$ distribution. In this respect, unlike the previous theoretical studies, we have shown that this distribution has a sign change at $xg0.3$ after evolution to the scale of available experimental data.