Simulation of Electron-Proton Scattering Events by a Feature-Augmented and Transformed Generative Adversarial Network (FAT-GAN)

We apply generative adversarial network (GAN) technology to build an event generator that simulates particle production in electron-proton scattering that is free of theoretical assumptions about underlying particle dynamics. The difficulty of efficiently training a GAN event simulator lies in learning the complicated patterns of the distributions of the particles physical properties. We develop a GAN that selects a set of transformed features from particle momenta that can be generated easily by the generator, and uses these to produce a set of augmented features that improve the sensitivity of the discriminator. The new Feature-Augmented and Transformed GAN (FAT-GAN) is able to faithfully reproduce the distribution of final state electron momenta in inclusive electron scattering, without the need for input derived from domain-based theoretical assumptions. The developed technology can play a significant role in boosting the science of existing and future accelerator facilities, such as the Electron-Ion Collider.

Measurement of the charged-current electron (anti-)neutrino inclusive cross-sections at the T2K off-axis near detector ND280

The electron (anti-)neutrino component of the T2K neutrino beam constitutes the largest background in the measurement of electron (anti-)neutrino appearance at the far detector. The electron neutrino scattering is measured directly with the T2K off-axis near detector, ND280. The selection of the electron (anti-)neutrino events in the plastic scintillator target from both neutrino and anti-neutrino mode beams is discussed in this paper. The flux integrated single differential charged-current inclusive electron (anti-)neutrino cross-sections, dσ/dp and dσ/d cos(θ), and the total cross-sections in a limited phase-space in momentum and scattering angle (p > 300 MeV/c and θ ≤ 45°) are measured using a binned maximum likelihood fit and compared to the neutrino Monte Carlo generator predictions, resulting in good agreement.

Comparison of optical potential for nucleons and $$\varDelta $$ resonances

Precise modeling of neutrino interactions on nuclear targets is essential for neutrino oscillations experiments. The modeling of the energy of final state particles in quasielastic (QE) scattering and resonance production on bound nucleons requires knowledge of both the removal energy of the initial state bound nucleon as well as the average Coulomb and nuclear optical potentials for final state leptons and hadrons. We extract the average values of the real part of the nuclear optical potential for final state nucleons ($$U_{opt}^{QE}$$UoptQE) as a function of the nucleon kinetic energy from inclusive electron scattering data on nuclear targets ($$_\mathbf{6 }^\mathbf{12 }{} \mathbf{C} $$612C+$$_\mathbf{8 }^\mathbf{16 }{} \mathbf{O} $$816O, $$_\mathbf{20 }^\mathbf{40 }{} \mathbf{Ca} $$2040Ca+$$_\mathbf{18 }^\mathbf{40 }{} \mathbf{Ar} $$1840Ar, $$_\mathbf{3 }^\mathbf{6 }{} \mathbf{Li} $$36Li, $$_\mathbf{18 }^\mathbf{27 }{} \mathbf{Al} $$1827Al, $$_\mathbf{26 }^\mathbf{56 }{} \mathbf{Fe} $$2656Fe, $$_\mathbf{82 }^\mathbf{208 }{} \mathbf{Pb} $$82208Pb) in the QE region and compare to calculations. We also extract values of the average of the real part of the nuclear optical potential for a $$\varDelta (1232)$$Δ(1232) resonance in the final state ($$U^\varDelta _{opt}$$UoptΔ) within the impulse approximation. We find that $$U^\varDelta _{opt}$$UoptΔ is more negative than $$U_{opt}^{QE}$$UoptQE with $$U^\varDelta _{opt}\approx $$UoptΔ≈1.5 $$U_{opt}^{QE}$$UoptQE for $$_\mathbf{6 }^\mathbf{12 }{} \mathbf{C} $$612C.

Towards a combined analysis of inclusive/exclusive electroproduction

In view of the major advances achieved by the CLAS experiments in studying the N* electroex citation amplitudes, as well as further extension of these studies in the experiments with CLAS12, we present an approach for the evaluation of the resonant contributions to inclusive electron scattering off protons. For the first time, the resonant contributions are determined from the experimental results on N* electrocouplings available from the data analyses of exclusive meson electroproduction off protons. This is a useful benchmark for future endeavours on understanding the transition region between low and high-energy regions, strongly related to tests on quark-hadron duality.