Engineering topics

Hung, Yu-Chun [Old Dominion University]

Publications and source records attributed to Hung, Yu-Chun [Old Dominion University].

3 records

DOE OSTI2026

Polarization observables 𝑇 and 𝐹 in the 𝛾⁢𝑝→𝜋 0 ⁢𝑝 reaction at CLAS

Pion photoproduction in the $\vec{γ}$$\vec{p}$ → π 0 p reaction has been measured in the FROzen Spin Target (FROST) experiment at the Thomas Jefferson National Accelerator Facility. In this experiment, circularly polarized photons with energies up to 3.082 GeV impinged on a transversely polarized frozen-spin target. Final-state protons were detected in the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer. The polarization observables T and F have been extracted for W from 1445 to 2525 MeV, of which the energy range is much broader, and the precision is better than the existing measurements in higher W ranges. The data generally agree with predictions of present partial-wave analyses but also show marked differences for higher W ranges. By incorporating the present data into the databases, the Scattering Analysis Interactive Data (SAID) fits have been improved with relatively small χ 2 and significant changes in the parameters of the (1910)1/2 + and N(2190)7/2 − have been found with the JüBo model.

particle production↗

DOE OSTI2026

Proton transparency and neutrino physics: New methods and modeling

Extracting accurate results from neutrino oscillation and cross section experiments requires accurate simulation of the neutrino-nucleus interaction. The rescattering of outgoing hadrons (final state interactions) by the rest of the nucleus is an important component of these interactions. We present a new measurement of proton transparency (defined as the fraction of outgoing protons that emerge without significant rescattering) using electron-nucleus scattering data recorded by the CLAS detector at Jefferson Laboratory on helium, carbon, and iron targets. This analysis uses a new data-driven method to extract the transparency. It defines transparency as the ratio of electron-scattering events with a detected proton to quasi-elastic electron-scattering events where a proton should have been knocked out. Our results are consistent with previous measurements that determined the transparency from the ratio of measured events to theoretically predicted events. We find that the GENIE event generator, which is widely used by oscillation experiments to simulate neutrino-nucleus interactions, needs to better describe both the nuclear ground state and proton rescattering in order to reproduce our measured transparency ratios, especially at lower proton momenta.

direct reactions↗

DOE OSTI2025

Recoil polarization in 𝐾 + ⁢𝑌 electroproduction in the nucleon resonance region with CLAS12

Hyperon recoil polarization measurements for the exclusive electroproduction of 𝐾 + ⁢Λ and 𝐾 + ⁢Σ 0 final states from an unpolarized proton target have been carried out using the CLAS12 spectrometer at Jefferson Laboratory. The measurements at beam energies of 6.535 and 7.546 GeV span the range of four-momentum transfer 𝑄 2 from 0.3 to 4.5GeV 2 and invariant mass 𝑊 from 1.6 to 2.4 GeV, while covering the full center-of-mass angular range of the 𝐾 + . These new Λ polarization observables extend the existing data in a similar kinematic range but from a significantly larger dataset. However, they represent the first electroproduction measurements of this observable for the Σ 0 . These data will allow for better exploration of the reaction mechanism in strangeness production, for further understanding of the spectrum and structure of excited nucleon states that couple to 𝐾⁢𝑌, and for improved insight into the strong interaction in the nonperturbative domain.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗