Determination of the pattern of nuclear binding from the data on lepton–nucleus deep inelastic scattering

Abstract.

Nucleon structure function ratios $r^A(x) = F_2^A(x)/F_2^{\mathrm {D}}(x)$ measured in the range of atomic masses $A \geq 4$ are analyzed with the aim of determining the pattern of the x and A dependence of $F_2(x)$ modifications caused by the nuclear environment. It is found that the x and A dependence of the deviations of the $r^A(x)$ from unity can be factorized in the entire range of x. The characteristic feature of the factorization is represented with the three cross-over points $x_i$, i = 1–3 in which $r^A(x)= 1$ independently of A. In the range $x > 0.7$ the pattern of $r^A(x)$ is fixed with $x_3 = 0.84 \pm 0.01$. The pattern of the x dependence is compared with theoretical calculations of Burov, Molochkov and Smirnov to demonstrate that the evolution of the nucleon structure as a function of A occurs in two stages: first for $A \leq 4$ and second for $A > 4$. The long-standing problem of the origin of the EMC effect is understood as a modification of the nucleon structure in the field responsible for the binding forces in a three-nucleon system.