The ratio $F_2^n/F_2^p$ from the analysis of data using a new scaling variable

Abstract

We analyze the proton and deuteron structure functions at large $x$ using a recently introduced scaling variable $\bar x$. This variable includes power corrections to $x$-scaling, and thus allows us to reach the Bjorken limit at moderate $Q^2$. Using available data we extract the ratio $F_2^n(x)/F_2^p(x)$ for $x\leq 0.85$. Contrary to earlier expectations this ratio tends to the value $\sim$2/3 for $x\to 1$, which corresponds to the quark model prediction for equal distributions of valence quarks.