Quark fracture function at small x from the Color Glass Condensate
Abstract
The target-fragmentation region in deeply inelastic electron-nucleus scattering provides insight into the partonic structure of the target, as hadrons measured in the final state retain information about the nonperturbative dynamics of spectator partons inside the nucleus. In QCD factorization theorems, this nonperturbative dynamics is encoded in objects known as fracture functions. In this paper, we study the extended quark fracture function in the limit where the struck (anti)quark carries a very small longitudinal momentum fraction, x. We first present an elementary derivation within the Color Glass Condensate effective field theory of the quark fracture function in terms of the dipole operator at small x. At the parton level, the quark extended fracture function is sensitive to gluon saturation when the transverse momentum P⊥ of the outgoing parton produced in the target-fragmentation region is smaller than the nuclear saturation scale Qs, in which regime the P⊥ distribution becomes approximately flat. We then show, through a numerical study that incorporates the convolution of this parton-level result with a collinear fragmentation function, that hadronization largely washes out these saturation effects, as the convolution predominantly probes partonic transverse momenta that are typically larger than Qs.
Related
- Gluonic nucleon energy correlators and fracture functions for Color Glass Condensate
- The signature-changing soft-gluon term as a possible source of non-planar ζ2 terms at small x in the non-singlet quark-plus-antiquark splitting function
- Reassessing the Connection Between the Color Glass Condensate and TMD PDFs
- One-nucleon intermediate-state contribution to the pion-coupled four-quark condensate in the N--J/ψ interaction
- Derivation of color projectors on multi-quark states using the Casimir operator
BibTeX
@misc{caucal2026quark,
title = {{Quark fracture function at small $x$ from the Color Glass Condensate}},
author = {Paul Caucal and Nolann Juet and Farid Salazar},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.16953},
eprint = {2609.16953},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.16953},
}
RIS
TY - UNPB
TI - Quark fracture function at small x from the Color Glass Condensate
AU - Paul Caucal
AU - Nolann Juet
AU - Farid Salazar
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.16953
UR - https://arxiv.org/abs/2609.16953
AB - The target-fragmentation region in deeply inelastic electron-nucleus scattering provides insight into the partonic structure of the target, as hadrons measured in the final state retain information about the nonperturbative dynamics of spectator partons inside the nucleus. In QCD factorization theorems, this nonperturbative dynamics is encoded in objects known as fracture functions. In this paper, we study the extended quark fracture function in the limit where the struck (anti)quark carries a very small longitudinal momentum fraction, x. We first present an elementary derivation within the Color Glass Condensate effective field theory of the quark fracture function in terms of the dipole operator at small x. At the parton level, the quark extended fracture function is sensitive to gluon saturation when the transverse momentum P_⊥ of the outgoing parton produced in the target-fragmentation region is smaller than the nuclear saturation scale Q_s, in which regime the P_⊥ distribution becomes approximately flat. We then show, through a numerical study that incorporates the convolution of this parton-level result with a collinear fragmentation function, that hadronization largely washes out these saturation effects, as the convolution predominantly probes partonic transverse momenta that are typically larger than Q_s.
ER -