Mon·Sep 27, 2021Monday·September 27, 2021

1. 01*

   Coexisting normal and intruder configurations in ${}^{32}$Mg

   N. Kitamura🇯🇵 · K. Wimmer🇯🇵 · A. Poves🇪🇸 · N. Shimizu🇯🇵 · J. A. Tostevin🇬🇧 · V. M. Bader🇺🇸 · C. Bancroft🇺🇸 · D. Barofsky🇺🇸 · T. Baugher🇺🇸 · D. Bazin🇺🇸 · J. S. Berryman🇺🇸 · V. Bildstein🇨🇦 and 16 other authors

   Situated in the so-called "island of inversion," the nucleus ${}^{32}$Mg is considered as an archetypal example of the disappearance of magicity at $N=20$. We report on high statistics in-beam spectroscopy of ${}^{32}$Mg with a unique approach, in that two direct reaction probes with different sensitivities to the underlying nuclear structure are employed at the same time. More specifically, states in ${}^{32}$Mg were populated by knockout reactions starting from ${}^{33}$Mg and ${}^{34}$Si, lying inside and outside the island of inversion, respectively. The momentum distributions of the reaction residues and the cross sections leading to the individual final states were confronted with eikonal-based reaction calculations, yielding a significantly updated level scheme for ${}^{32}$Mg and spin-parity assignments. By fully exploiting observables obtained in this measurement, a variety of structures coexisting in 32Mg was unraveled. Comparisons with theoretical predictions based on shell-model overlaps allowed for clear discrimination between different structural models, revealing that the complete theoretical description of this key nucleus is yet to be achieved.

   nucl-exPLB(2021)·13 citations
2. 02*

   Revealing pion and kaon structure via generalised parton distributions

   Khepani Raya🇨🇳 · Zhu-Fang Cui🇨🇳 · Lei Chang🇨🇳 · Jose-Manuel Morgado🇪🇸 · Craig D. Roberts🇨🇳 · Jose Rodriguez-Quintero🇪🇸

   Clear windows onto emergent hadron mass (EHM) and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure, many of which are accessible via generalised parton distributions (GPDs). Beginning with algebraic GPD Ansaetze, constrained entirely by hadron-scale $\pi$ and $K$ valence-parton distribution functions (DFs), in whose forms both EHM and Higgs boson influences are manifest, numerous illustrations are provided. They include the properties of electromagnetic form factors, impact parameter space GPDs, gravitational form factors and associated pressure profiles, and the character and consequences of all-orders evolution. The analyses predict that mass-squared gravitational form factors are stiffer than electromagnetic form factors; reveal that $K$ pressure profiles are tighter than $\pi$ profiles, with both mesons sustaining near-core pressures at magnitudes similar to that expected at the core of neutron stars; deliver parameter-free predictions for $\pi$ and $K$ valence, glue, and sea GPDs at the resolving scale $\zeta =2$GeV; and predict that at this scale the fraction of meson mass-squared carried by glue and sea combined matches that lodged with the valence degrees-of-freedom, with a similar statement holding for mass-squared radii.

   ↳ hep-phhep-exhep-latnucl-ex+1CPC(2022)·83 citations
3. 03*

   Exploring the ${\Sigma }^{+}p$ interaction by measurements of the correlation function

   J. Haidenbauer🇩🇪 · U.-G. Meißner🇩🇪

   The spin-dependent components of the fundamental hyperon-nucleon interactions are largely unknown. We show that under reasonable assumptions, a measurement of the ${\Sigma }^{+}p$ correlation function in high-energy proton-proton or heavy-ion collisions combined with cross section data allows to separate the singlet and the triplet $S$-wave contributions.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2022)·20 citations
4. 04*

   Geant4-based calibration of an organic liquid scintillator

   N. Mauritzson🇸🇪 · K.G. Fissum🇸🇪 · H. Perrey🇸🇪 · J.R.M. Annand🇬🇧 · R.J.W. Frost🇸🇪 · R. Hall-Wilton🇸🇪 · R. Al Jebali🇸🇪 · K. Kanaki🇸🇪 · V. Maulerova🇸🇪 · F. Messi🇸🇪 · E. Rofors🇸🇪

   A light-yield calibration of an NE 213A organic liquid scintillator detector has been performed using both monoenergetic and polyenergetic gamma-ray sources. Scintillation light was detected in a photomultiplier tube, and the corresponding pulses were subjected to waveform digitization on an event-by-event basis. The resulting Compton edges have been analyzed using a Geant4 simulation of the detector which models both the interactions of the ionizing radiation as well as the transport of scintillation photons. The simulation is calibrated and also compared to well-established prescriptions used to determine the Compton edges, resulting ultimately in light-yield calibration functions. In the process, the simulation-based method produced information on the gain and intrinsic pulse-height resolution of the detector. It also facilitated a previously inaccessible understanding of the systematic uncertainties associated with the calibration of the scintillation-light yield. The simulation-based method was also compared to well-established numerical prescriptions for locating the Compton edges. Ultimately, the simulation predicted as much as 17% lower light-yield calibrations than the prescriptions. These calibrations indicate that approximately 35% of the scintillation light associated with a given gamma-ray reaches the photocathode. It is remarkable how well two 50 year old prescriptions for calibrating scintillation-light yield in organic scintillators have stood the test of time.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2022)·4 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.