Progress on nuclear modifications of structure functions

TL;DR

This paper discusses recent progress in understanding nuclear modifications of structure functions, introduces a new tensor structure function for the deuteron, and highlights implications for QCD, heavy-ion collisions, and neutrino physics.

Contribution

It presents new insights into nuclear modifications of structure functions and introduces a novel tensor-polarized structure function for the deuteron, challenging conventional models.

Findings

Inconsistency of HERMES data with standard deuteron models

Indication of new hadronic phenomena in tensor-polarized deuterons

Potential experimental investigations at JLab from 2010s

Abstract

We report progress on nuclear structure functions, especially on their nuclear modifications and a new tensor structure function for the deuteron. To understand nuclear structure functions is an important step toward describing nuclei and QCD matters from low to high densities and from low to high energies in terms of fundamental quark and gluon degrees of freedom beyond conventional hadron and nuclear physics. It is also practically important for understanding new phenomena in high-energy heavy-ion collisions at RHIC and LHC. Furthermore, since systematic errors of current neutrino-oscillation experiments are dominated by uncertainties of neutrino-nucleus interactions, such studies are valuable for finding new physics beyond current framework. Next, a new tensor-polarized structure function $b_1$ is discussed for the deuteron. There was a measurement by HERMES; however, its data are inconsistent with the conventional convolution estimate based on the standard deuteron model with D-state admixture. This fact suggests that a new hadronic phenomenon should exist in the tensor-polarized deuteron at high energies, and it will be experimentally investigated at JLab from the end of 2010's.