Mon·Aug 29, 2022Monday·August 29, 2022

1. 01*

   Measurements of the ${}^{27}\mathrm{Al}(\alpha ,n)$ Thick Target Yield Near Threshold

   K. Brandenburg🇲🇽 · G. Hamad🇺🇸 · Z. Meisel🇺🇸 · C. R. Brune🇺🇸 · D. E. Carter · J. Derkin🇲🇽 · D. C. Ingram · Y. Jones-Alberty🇲🇽 · B. Kenady · T. N. Massey🇺🇸 · M. Saxena🇺🇸 · D. Soltesz🇺🇸 · S. K. Subedi🇺🇸 · J. Warren

   We present results from direct measurements of the ${}^{27}\mathrm{Al}(\alpha ,n)$ thick target yield from laboratory incident energies $E_{\alpha }\approx$ 3$-$5~MeV, performed with the ${}^3$HeBF${}_3$ Giant Barrel (HeBGB) neutron detector at the Edwards Accelerator Laboratory. Our measurements have a small energy cadence in order to address discrepancies and sparseness of thick-target yield data sets existing for this energy region. We find general agreement with existing data sets, including yields derived from cross section data, while resolving a discrepancy between existing thick-target yield data sets for $E_{\alpha }\approx 4-5$~MeV. However, for $E_{\alpha }<3.5$~MeV, our results are substantially lower than previous thick-target yield data and somewhat larger than yields calculated from existing cross section data. Our data complete the energy-range needed for estimates of the ${}^{27}\mathrm{Al}(\alpha ,n)$ contribution to neutrino and dark matter detector backgrounds and result in increased viability of ${}^{27}\mathrm{Al}(\alpha ,n)$ as a plasma diagnostic tool at fusion facilities such as the National Ignition Facility.

   nucl-exNucl.Sci.Eng.(2023)·2 citations
2. 02*

   Underground Measurements of Nuclear Reaction Cross-Sections Relevant to AGB Stars

   Chemseddine Ananna · Francesco Barile🇮🇹 · Axel Boeltzig🇩🇪 · Carlo Giulio Bruno🇬🇧 · Francesca Cavanna🇮🇹 · Giovanni Francesco Ciani🇮🇹 · Alessandro Compagnucci · Laszlo Csedreki🇮🇹 · Rosanna Depalo🇮🇹 · Federico Ferraro🇮🇹 · Eliana Masha🇮🇹 · Denise Piatti🇮🇹 · David Rapagnani🇮🇹 · Jakub Skowronski🇮🇹

   Nuclear reaction cross sections are essential ingredients to predict the evolution of AGB stars and understand their impact on the chemical evolution of our Galaxy. Unfortunately, the cross sections of the reactions involved are often very small and challenging to measure in laboratories on Earth. In this context, major steps forward were made with the advent of underground nuclear astrophysics, pioneered by the Laboratory for Underground Nuclear Astrophysics (LUNA). The present paper reviews the contribution of LUNA to our understanding of the evolution of AGB stars and related nucleosynthesis.

   nucl-exUniverse(2022)·5 citations
3. 03*

   Wave functions of $(I,J^P)=(\frac{1}{2},{\frac{3}{2}}^{\mp })$ baryons

   Langtian Liu🇨🇳 · Chen Chen🇨🇳 · Craig D. Roberts🇨🇳

   Using a Poincaré-covariant quark+diquark Faddeev equation, we provide structural information on the four lightest $(I,J^P)=(\frac{1}{2},{\frac{3}{2}}^{\mp })$ baryon multiplets. These systems may contain five distinct types of diquarks; but in order to obtain reliable results, it is sufficient to retain only isoscalar-scalar and isovector-axialvector correlations, with the latter being especially important. Viewed with low resolution, the Faddeev equation description of these states bears some resemblance to the associated quark model pictures; namely, they form a set of states related via orbital angular momentum excitation: the negative parity states are primarily $\mathsf{P}$-wave in character, whereas the positive parity states are $\mathsf{D}$ wave. However, a closer look reveals far greater structural complexity than is typical of quark model descriptions, with $\mathsf{P}$, $\mathsf{D}$, $\mathsf{S}$, $\mathsf{F}$ waves and interferences between them all playing a large role in forming observables. Large momentum transfer resonance electroexcitation measurements can be used to test these predictions and may thereby provide insights into the nature of emergent hadron mass.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2023)·23 citations
4. 04*

   Rescattering effect on the measurement of K* spin alignment in heavy-ion collisions

   Ziyang Li🇨🇳 · Wangmei Zha🇨🇳 · Zebo Tang🇨🇳

   Spin alignment of vector mesons in noncentral relativistic heavy ion collisions provides a novel probe of the global quark polarization and hadronization mechanism. In this paper, we discuss the spin alignment of a short-lived vector meson, namely K*, arising from the hadronic rescattering process using the UrQMD model. This spin alignment is not related to global quark polarization but cannot be distinguished from those arising from global quark polarization in experiments. The spin alignment parameter ${\rho }_{00}$ is found to deviate from 1/3 by up to -0.008 (0.03) with respect to the reaction (production) plane. These deviations are much larger than the expected signal from all the theoretical models implementing the conventional global quark polarization mechanism as well as the current experimental precision, and should be considered seriously when comparing measurements with theoretical calculations.

   ↳ nucl-thnucl-exPRC(2022)·13 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.