Suppression of diffraction in DIS on nuclei and dynamical mechanism of leading twist nuclear shadowing

TL;DR

This paper uses the leading twist approach to analyze nuclear shadowing in deep inelastic scattering, showing suppression of diffraction and its relation to the saturation scale, with implications for understanding nuclear effects in high-energy physics.

Contribution

It demonstrates that the ratio of diffractive to total DIS cross sections in nuclei is controlled by an effective dipole cross section, providing new insights into nuclear shadowing mechanisms.

Findings

The ratio R_diff/tot is approximately 0.5-1 for nuclei, contrasting with dipole model predictions.

R_diff/tot approaches 1 in the black disk limit, indicating diffraction suppression.

Nuclear shadowing depletes the enhancement of the saturation scale in nuclei.

Abstract

Using the leading twist approach (LTA) to nuclear shadowing (NS), we calculate the ratio of the diffractive-to-total DIS cross sections $R_{\rm diff/tot}$ for a heavy nucleus and proton and confirm that $R_{\rm diff/tot} \approx 0.5-1$ in contrast with $R_{\rm diff/tot} \approx 1.5-2$ in the dipole model. We show that the magnitude of $R_{\rm diff/tot}$ is controlled by an effective dipole cross section so that $R_{\rm diff/tot} \to 1$ in the black disk limit. We also argue that strong leading twist NS as well as the dilute nuclear density deplete nuclear enhancement of the saturation scale leading to $Q_{sA}^2(b=0)/Q_{sp}^2(b=0) \sim 1$.