Thu·Sep 21, 2023Thursday·September 21, 2023

1. 01*

   Methodology for measuring photonuclear reaction cross sections with an electron accelerator based on Bayesian analysis

   Saverio Braccini · Pierluigi Casolaro · Gaia Dellepiane · Christian Kottler · Matthias Lüthi · Lorenzo Mercolli · Peter Peier · Paola Scampoli🇨🇭 · Andreas Türler

   Accurate measurements of photonuclear reaction cross sections are crucial for a number of applications, including radiation shielding design, absorbed dose calculations, reactor physics and engineering, nuclear safeguard and inspection, astrophysics, and nuclear medicine. Primarily motivated by the study of the production of selected radionuclides with high-energy photon beams (mainly 225Ac, 47Sc, and 67Cu), we have established a methodology for the measurement of photonuclear reaction cross sections with the microtron accelerator available at the Swiss Federal Institute of Metrology (METAS). The proposed methodology is based on the measurement of the produced activity with a High Purity Germanium (HPGe) spectrometer and on the knowledge of the photon fluence spectrum through Monte Carlo simulations. The data analysis is performed by applying a Bayesian fitting procedure to the experimental data and by assuming a functional trend of the cross section, in our case a Breit-Wigner function. We validated the entire methodology by measuring a well-established photonuclear cross section, namely the 197Au({\gamma},n)196Au reaction. The results are consistent with those reported in the literature.

   nucl-exphysics.ins-detAppl.Radiat.Isot.(2024)·0 citations
2. 02*

   Tetraquark mixing model is superior to meson molecules in explaining two light-meson nonets

   Hungchong Kim🇰🇷 · K.S.Kim🇰🇷

   In this work, we compare the tetraquark mixing model and meson molecules in describing the two physical nonets in the $J^P=0^{+}$ channel, the light nonet [$a_0(980)$, $K_0^{\ast }(700)$, $f_0(500)$, $f_0(980)$] and the heavy nonet [$a_0(1450)$, $K_0^{\ast }(1430)$, $f_0(1370)$, $f_0(1500)$]. In particular, we focus on whether successful aspects of the tetraquark mixing model that apply to all members of each nonet can be reproduced from a model of meson molecules. By combining two mesons in the lowest-lying pseudoscalar nonet, we construct SU${}_f$(3) molecular nonets that can be tested for the two physical nonets. This molecular approach can make two flavor nonets just as the tetraquark mixing model but this model has some difficulties in describing the universal features of the two nonets %Because of this, this molecular model cannot reproduce successful aspects of the tetraquark mixing model, such as mass splitting between the two nonets, and enhancement or suppression of the coupling strengths of the two nonets into two pseudoscalar mesons. We also compare the fall-apart modes of the tetraquark mixing model and the two-meson modes from the molecular model. A clear distinction can be seen by the two-pion modes in the isovector resonances. The two-pion modes appear in the molecular model, but not in the tetraquark mixing model. The absence of the two-pion modes is supported by the experimental decay modes of the isovector resonances.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2023)·3 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.