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DOE OSTI Β· 3023996

Small-π‘₯ Factorization in the Target Fragmentation Region

Caucal, Paul [IMT Atlantique, Nantes (France); UniversitΓ© de Nantes (France); Centre National de la Recherche Scientifique (CNRS), Nantes (France). Inst. National de Physique Nucleaire et de Physique des Particules (IN2P3), SUBATECH] (ORCID:0000000290331473)Β·Salazar, Farid [Temple University, Philadelphia, PA (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); University of Washington, Seattle, WA (Untied States)] (ORCID:0000000240076136)
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Abstract

We consider the differential cross-section for single-inclusive jet production with transverse momentum 𝑃 βŠ₯ in deep inelastic scattering at small Bjorken π‘₯ Bj , mediated by a virtual photon with virtuality 𝑄 2 . Unlike most studies at small π‘₯, which focus on particle production in the current fragmentation region, we investigate the kinematic regime where the jet is produced in the target fragmentation hemisphere of the Breit frame, and with 𝑃 βŠ₯ β‰ͺ 𝑄. For a longitudinally polarized photon, we demonstrate that this cross section is not power suppressed in 𝑃 βŠ₯ /𝑄 and we derive a factorized expression in terms of extended quark and gluon jet fracture functions. Our formula, valid at next-to-leading order in 𝛼 𝑠 at small π‘₯, is akin to the Altarelli-Martinelli identity for the longitudinal DIS structure function. Numerical estimates show that the extended quark jet fracture function is the most sensitive to saturation effects in large nuclei.

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS

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Caucal, Paul [IMT Atlantique, Nantes (France); UniversitΓ© de Nantes (France); Centre National de la Recherche Scientifique (CNRS), Nantes (France). Inst. National de Physique Nucleaire et de Physique des Particules (IN2P3), SUBATECH] (ORCID:0000000290331473), Salazar, Farid [Temple University, Philadelphia, PA (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); University of Washington, Seattle, WA (Untied States)] (ORCID:0000000240076136). 2026-02-23. Small-π‘₯ Factorization in the Target Fragmentation Region. https://doi.org/10.1103/3b6j-th2m

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