Systematic effective-field-theory operator expansion for saturation-scale matching

Construct a systematic effective-field-theory operator expansion for matching the nuclear light-front stress tensor or thickness function to the saturation scale, including subleading short-range structures, transverse-gradient corrections, and higher-body operators.

Background

The paper uses a leading coarse-grained relation between the nuclear thickness function and the local saturation momentum, namely that the squared saturation scale is proportional to the thickness. The omitted terms may contain short-range structures, transverse-gradient corrections, and higher-body operators. A systematic operator expansion would organize these corrections and provide an effective-field-theory foundation for the matching between incoming nuclear structure and the produced collision field.

The authors explicitly identify this construction as unfinished and defer it to future work. This is unresolved rather than merely aspirational because the desired expansion is specified together with the classes of corrections it must incorporate.