Due to its conceptual simplicity, Deeply Inelastic Scattering (DIS) often serves as a textbook example for Quantum Chromo Dynamics (QCD) and partonic structure of nucleons. However, it is this supposed simplicity, which makes DIS an ideal case for discussing many additional effects and corrections. In these lectures we discuss DIS within the domain of perturbative QCD covering a range of topics ranging from mathematical problems to kinematical corrections, and to practical challenges when attempting to interpret experimental measurements. Although here we focus on the exemplary case of DIS, the discussed topcis are relevant to a larger class of processes. We also give an overview of existing and future DIS measurements, and discuss their implementation into modern extractions of parton distribution functions (PDFs) which quantify the partonic structure of nucleons. The discussed features are all implemented in the open source code Yadism, which has been used for PDF extractions from a wide range of the available world data on fully inclusive DIS.
In these notes, basic concepts and necessary formulas for the modeling of elastic lepton-nucleon and quasielastic lepton-nucleus scattering using relativistic models are discussed. Certain theoretical developments are presented in meticulous detail, particularly those rarely found in papers or standard textbooks. In order to highlight the discrepancies between models and evaluate the impact of various nuclear effects, theoretical predictions are compared with inclusive electron scattering data. These notes are designed for Master's or PhD students embarking on their research in the field of neutrino-nucleus interactions at intermediate energies (ranging from several hundred MeV to a few GeV). They are intended to serve as a supplemental guide, never as a substitute for traditional textbooks on Scattering Theory and Quantum Field Theory. Currently, these notes are included in the course `Relativistic Quantum Theory: Nuclear Processes', which is integrated into both the Interuniversity Master in Nuclear Physics (https://master.us.es/fisicanuclear/index.php/) and the Erasmus Mundus Joint Master Degree in Nuclear Physics (https://www.emm-nucphys.eu/en), with the University of Seville as one of the partner institutions. Previously, this material was part of the course `Weak Interactions', within the same Master's programs.
Semi-inclusive deep-inelastic scattering (SIDIS) of leptons is a vital tool for probing the three-dimensional momentum space partonic structure of the nucleon. Reliable extraction of the intrinsic collinear or transverse momentum dependent parton distributions from SIDIS data requires careful treatment of QED radiative effects beyond the Born level. In this work we perform a detailed comparative analysis of QED effects in SIDIS using the traditional Bardin-Shumeiko approach, augmented by the electron structure function method, and a more recent factorized approach that treats QED and QCD radiation on equal footing. We compare analytical and numerical results of these approaches for the unpolarized $\pi^+$ electroproduction cross sections off the proton and the Collins and Sivers transverse single-spin asymmetries, and identify the sources of discrepancies between the calculations, which for the cross sections can reach up to $\approx 2\%$, $\approx 7\%$, and $\approx 5\%$ at Jefferson Lab, HERMES, and EIC kinematics, respectively. To provide a unified approach for reliably extracting partonic information from future SIDIS measurements, we propose a hybrid framework that employs the salient features of both frameworks in their respective regions of applicability.
I. Akushevich, Haiyan Gao, A. Ilyichev et al.· 0 citations
Deep-inelastic scattering (DIS) provides a powerful probe of physics beyond the Standard Model through precision measurements interpreted within the Standard Model Effective Field Theory (SMEFT). We study the impact of collision-induced QED radiation on SMEFT constraints using the joint QCD+QED factorization framework based on lepton distribution and fragmentation functions. QED radiation can substantially modify DIS cross sections and, in some kinematic regions, significantly alter the effective momentum transfer relevant for factorization. We find that while cross sections receive order-one corrections, longitudinal electron spin asymmetries are affected only at the few-percent level, making them significantly more robust observables for SMEFT studies. Benchmark projections for SoLID and the Electron-Ion Collider are provided to demonstrate the impact of QED radiation for future precision DIS analyses and the extraction of SMEFT constraints.
S. Mantry, Jian-Wei Qiu, Jia-Yue Zhang· 0 citations
We study the production of $c$ and $b$ quarks in photon-induced processes as a probe of gluon saturation, with a focus on the high-energy region accessible in ultra-peripheral collisions (UPCs) at the LHC. We compare predictions for inclusive and diffractive heavy quark production with and without saturation effects by using the nonlinear Balitsky--Kovchegov and the linear Balitsky--Fadin--Kuraev--Lipatov equations for the evolution of the dipole amplitude. The percentage of coherent diffractive events is predicted to be $~20\%$ in the saturation model, which is approximately twice as large as predictions based on parton distribution functions and shadowing. This indicates that measurements of diffractive heavy quark production in UPCs may provide a sensitive probe for distinguishing linear and nonlinear regimes of quantum chromodynamics.
Jani Penttala, C. Royon, Jarno Vierros· 0 citations
We show that the hierarchy of quantum correlations produced in deep-inelastic scattering (DIS) can serve as a novel probe of the proton's nonperturbative structure. Specifically, we show that quantum entanglement, discord, steering, and magic provide nontrivial and complementary sensitivities to the nucleon's parton distribution functions (PDFs), particularly those encoding the transverse-spin polarization of the interacting quark. This connection leads to a unique probe of the proton's parton-level tensor charges with implications for beyond Standard Model (BSM) physics searches. We propose how quantum information measures can be utilized for precision studies of hadron structure at DIS experiments like the upcoming Electron-Ion Collider (EIC).
We begin by summarizing a study of the ϕ
N
correlation function, motivated by recent femtoscopy measurements reported by the ALICE Collaboration. The analysis is carried out within a hadronic effective Lagrangian framework incorporating coupled-channel dynamics, and yields a quantitative description of the experimental data. We then present an overview of results from transport-model simulations of 12 GeV pA reactions, aimed at investigating the behavior of the ϕ meson in nuclear matter. Particular emphasis is placed on the underlying production mechanisms of the ϕ meson and their impact on the resulting dilepton spectra. Finally, QCD sum rule predictions on the modifications of the two independent polariation modes of the ϕ meson, which could be studied at the J-PARC E16 and/or E88 experiments, will also be discussed.
P. Gubler· EPJ Web of Conferences· 0 citations
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