arXiv subjects

Diego Padilla

Publications and source records attributed to Diego Padilla.

4 recordsLinked to original sources

arXiv2026

One-point charge correlator as a probe for the odderon

We propose the one-point charge correlator (OPCC) in transversely polarized deep inelastic scattering as a new probe of the spin-dependent odderon. The OPCC is an infrared and collinear safe observable constructed solely from the charge and angular information of final-state charged particles. Because the charge weight is odd under charge conjugation, the contribution of the C-even pomeron to the OPCC vanishes identically in the small-$x$ eikonal limit, whereas the contribution of the C-odd spin-dependent odderon survives. We define a transverse single-spin asymmetry by normalizing the spin-dependent OPCC to the unpolarized charged-hadron one-point energy correlator. At small $x$, this asymmetry reduces to a ratio of spin-dependent odderon and pomeron contributions. We provide illustrative estimates of this asymmetry for Electron-Ion Collider kinematics within the small-$x$ dipole framework with Balitsky--Kovchegov evolution to guide experimental studies. Dedicated measurements of the OPCC asymmetry with a transversely polarized proton beam would provide new quantitative constraints on the currently unconstrained spin-dependent odderon.

hep-ph↗

arXiv2026

Probing the Sivers Asymmetry with Transverse Energy-Energy Correlators in the Small-$x$ Regime

We investigate transverse energy-energy correlators (TEECs) for both polarized and unpolarized targets in the small-$x$ regime at the Electron-Ion Collider (EIC). Focusing on the approximately back-to-back electroproduction of a hadron-electron pair, we apply transverse-momentum-dependent (TMD) factorization formulas that incorporate TMD evolution for both event-shape observables and expand them in terms of the small-$x$ dipole amplitude. This allows us to write the TEEC off the transversely polarized proton in terms of a C-odd interaction, corresponding to an odderon exchange. Due to the charge-conjugation-odd nature of the small-$x$ quark Sivers function, we restrict the sum over final hadronic states to positively and negatively charged hadrons separately. We present numerical predictions for the TEEC Sivers asymmetry at the EIC and find the magnitude of the asymmetry to be on the $0.01 \%$ level. This channel offers a promising avenue for benchmarking the still largely unconstrained odderon amplitude.

hep-ph↗

arXiv2026

Parton distributions in the shockwave formalism

In this work, we calculate a broad class of parton distributions - including parton distribution functions (PDFs), transverse-momentum-dependent distributions (TMDs), generalized parton distributions (GPDs), generalized transverse-momentum-dependent distributions (GTMDs), and diffractive parton distributions - directly from their operator-level definition in the shockwave approximation for the target nucleon. This approximation is valid in the high-energy limit of scattering, corresponding to the small-$x$ regime. The shockwave framework allows us to employ the eikonal approximation and express the parton distributions in terms of Wilson-line correlators, naturally formulated within the color-glass condensate effective field theory. We present a comprehensive set of Feynman rules for evaluating parton distributions in this limit, and demonstrate how they can be systematically applied to calculate all phenomenologically relevant leading-twist parton distributions at leading order. This work establishes a unified starting point for future studies that aim to bridge the color-glass condensate approach with the partonic description of the nucleon.

hep-ph↗

arXiv2026

Matching collinear factorization with color-glass condensate for inclusive and exclusive deep inelastic scattering

Collinear factorization and color-glass condensate (CGC) effective field theory are generally treated as separate approaches for calculating scattering amplitudes, valid in different kinematic regimes. For deep inelastic scattering at high photon virtuality and high center-of-mass energy, however, both of these approaches should be applicable. By expressing collinear parton distributions and generalized parton distributions in the shockwave approximation, we show that the resulting collinear-factorization amplitudes exactly reproduce the large-$Q^2$ expansion of CGC amplitudes for inclusive deep inelastic scattering, deeply virtual Compton scattering, and deeply virtual meson production. The matching holds directly at the amplitude level and includes both logarithmically enhanced and finite contributions. Our results establish the consistency between collinear factorization and the CGC in their common region of validity, clarify the origin of large momentum logarithms within the CGC framework, and provide a path toward combining high-energy and collinear evolution in a unified description of hadronic structure at small $x$ and large momentum scales.

hep-ph↗