Investigation of proton structure function $F_2 ^p$ at HERA in light of an analytical solution to Balitsky-Kovchegov equation

Abstract

In this paper, the proton structure function $F_2 ^p (x,Q^2)$ at small-$x$ is investigated using an analytical solution of the Balitsky-Kovchegov (BK) equation. In the context of the color dipole description of deep inelastic scattering (DIS), the structure function $F_2 ^p (x,Q^2)$ is computed by applying the analytical expression for the scattering amplitude $N(k,Y)$ derived from the BK solution. At transverse momentum $k$ and total rapidity $Y$, the scattering amplitude $N(k,Y)$ represents the propagation of the quark-antiquark dipole in the color dipole description of DIS. Using the BK solution we extracted the integrated gluon density $xg(x,Q^2)$ and then compared our theoretical estimation with the LHAPDF global data fits NNPDF3.1sx and CT18. Finally, we investigated the behavior of $F_2 ^p (x,Q^2)$ in the kinematic region of $10^{-5} \leq x \leq 10^{-2}$ and $2.5$ $GeV^{2}$ $\leq$ $Q^2$ $\leq$ $60$ $GeV^{2}$. Our predicted results for $F_2 ^p (x,Q^2)$ within the specified kinematic region are in good agreement with the recent high-precision data for $F_2 ^p (x,Q^2)$ from HERA (H1 Collaboration) and the LHAPDF global parametrization group NNPDF3.1sx.