arXiv subjects

Pierre Chatagnon

Publications and source records attributed to Pierre Chatagnon.

3 recordsLinked to original sources

arXiv2026

Validating a BDT-based Electron-Positron Identification Algorithm at CLAS12 with Experimental Data

This article presents a machine-learning, particle-identification algorithm for electrons and positrons in the CLAS12 experiment. The main objective was to minimize charged-pion contamination for both experimental and simulated data. We developed, evaluated and validated two BDT models with different input features, both trained on simulated samples, and conducted rigorous validation using both simulated and experimental data to ensure reliability. Our results show the effectiveness of the applied models in mitigating background contamination. By retaining more than 90\% of leptons in the simulated samples, the charged-pion background is largely reduced. Performance was evaluated on experimental data, providing a framework to validate such approaches at CLAS12 and future electron-beam facilities.

hep-ex↗

arXiv2024

Exploring Baryon Resonances with Transition Generalized Parton Distributions: Status and Perspectives

QCD gives rise to a rich spectrum of excited baryon states. Understanding their internal structure is important for many areas of nuclear physics, such as nuclear forces, dense matter, and neutrino-nucleus interactions. Generalized parton distributions (GPDs) are an established tool for characterizing the QCD structure of the ground-state nucleon. They are used to create 3D tomographic images of the quark/gluon structure and quantify the mechanical properties such as the distribution of mass, angular momentum and forces in the system. Transition GPDs extend these concepts to $N \rightarrow N^\ast$ transitions and can be used to characterize the 3D structure and mechanical properties of baryon resonances. They can be probed in high-momentum-transfer exclusive electroproduction processes with resonance transitions $e + N \rightarrow e' + M + N^\ast$, such as deeply-virtual Compton scattering ($M = \gamma$) or meson production ($M = \pi, K$, $etc.$), and in related photon/hadron-induced processes. This White Paper describes a research program aiming to explore baryon resonance structure with transition GPDs. This includes the properties and interpretation of the transition GPDs, theoretical methods for structures and processes, first experimental results from JLab 12 GeV, future measurements with existing and planned facilities (JLab detector and energy upgrades, COMPASS/AMBER, EIC, EicC, J-PARC, LHC ultraperihperal collisions), and the theoretical and experimental developments needed to realize this program.

hep-ph↗

arXiv2021

Deeply virtual Compton scattering on the neutron with positron beam

Measuring DVCS on a neutron target is a necessary step to deepen our understanding of the structure of the nucleon in terms of Generalized Parton Distributions (GPDs). The combination of neutron and proton targets allows to perform a flavor decomposition of the GPDs. Moreover, neutron-DVCS plays a complementary role to DVCS on a transversely polarized proton target in the determination of the GPD $E$, the least known and constrained GPD that enters Ji's angular momentum sum rule. A measurement of the beam-charge asymmetry (BCA) in the $e^{\pm} d\to e^{\pm}nγ(p)$ reaction can significantly impact the experimental determination of the real parts of the $E$ and, to a lesser extent, $\widetilde{H}$ GPDs.

nucl-ex↗