Global Study of Nuclear Structure Functions
S. A. Kulagin, R. Petti
TL;DR
This work develops a comprehensive phenomenological framework for nuclear deep-inelastic scattering that combines incoherent scattering from bound nucleons with coherent shadowing, explicitly including Fermi motion, binding, pion excess, and off-shell modifications of bound nucleons. The model uses a nonrelativistic spectral function plus a constrained pion distribution and introduces universal off-shell corrections and an effective hadronic-scattering amplitude to describe nuclear effects across a wide x and Q^2 range. After fitting to extensive nuclear DIS data with MINUIT, the authors achieve excellent agreement across many nuclei and extract a small set of universal parameters, providing predictive power for deuteron structure, nuclear parton distributions, and neutrino scattering. The framework connects light-cone momentum balance, sum-rule constraints, and nuclear geometry to quantify how the nuclear medium alters quark and gluon distributions in a controlled, testable way.
Abstract
We present the results of a phenomenological study of unpolarized nuclear structure functions for a wide kinematical region of x and Q^2. As a basis of our phenomenology we develop a model which takes into account a number of different nuclear effects including nuclear shadowing, Fermi motion and binding, nuclear pion excess and off-shell correction to bound nucleon structure functions. Within this approach we perform a statistical analysis of available data on the ratio of the nuclear structure functions F_2 for different nuclei in the range from the deuteron to the lead. We express the off-shell effect and the effective scattering amplitude describing nuclear shadowing in terms of few parameters which are common to all nuclei and have a clear physical interpretation. The parameters are then extracted from statistical analysis of data. As a result, we obtain an excellent overall agreement between our calculations and data in the entire kinematical region of x and Q^2. We discuss a number of applications of our model which include the calculation of the deuteron structure functions, nuclear valence and sea quark distributions and nuclear structure functions for neutrino charged-current scattering.