Thu·Mar 28, 2024Thursday·March 28, 2024

1. 01*

   Role of hidden-color components in the tetraquark mixing model

   Hungchong Kim🇰🇷 · K.S.Kim🇰🇷

   Multiquarks can have two-hadron components and hidden-color components in their wave functions. The presence of two-hadron components in multiquarks introduces a potential source of confusion, particularly with respect to their resemblance to hadronic molecules. On the other hand, hidden-color components are essential for distinguishing between multiquarks and hadronic molecules. In this work, we study the hidden-color components in the wave functions of the tetraquark mixing model, a model that has been proposed as a suitable framework for describing the properties of two 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 [$a_0(1450)$, $K_0^{\ast }(1430)$, $f_0(1370)$, $f_0(1500)$]. Our analysis reveals a substantial presence of hidden-color components within the tetraquark wave functions. To elucidate the impact of hidden-color components on physical quantities, we conduct computations of the hyperfine masses, $⟨V_{CS}⟩$, for the two nonets, considering scenarios involving only the two-meson components and those incorporating the hidden-color components. We demonstrate that the hidden-color components constitute an important part of the hyperfine masses, such that the mass difference formula, $\Delta M\approx \Delta ⟨V_{CS}⟩$, which has been successful for the two nonets, cannot be achieved without the hidden-color contributions. This can provide another evidence supporting the tetraquark nature of the two nonets.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2024)·5 citations
2. 02*

   Uncertainty quantification in $(p,n)$ reactions

   A. J. Smith🇬🇧 · C. Hebborn🇺🇸 · F. M. Nunes🇺🇸 · R. G. T. Zegers🇺🇸

   Charge-exchange reactions are versatile probes for nuclear structure. In particular, when populating isobaric analog states, these reactions are used to study isovector nuclear densities and neutron skins. The quality of the information extracted from charge-exchange data depends on the accuracy of the reaction models and their inputs; this work addresses these two points. First, we quantify the uncertainties due to effective nucleon-nucleus interactions by propagating the parameter posterior distributions of the recent global optical model KDUQ [1] to $(p,n)$ reaction observables populating the isobaric analogue state, at beam energies in the range of $25-160$ MeV. Our analysis, focusing on ${}^{48}$Ca, shows that the total parametric uncertainties on the cross sections are around 60-100%. The source of this uncertainty is mainly the transition operator as the uncertainties from the distorted waves alone are less than about 15%. Second, we perform a comparison between two- and three-body models that both describe the dynamics of the reaction within the DWBA. The predictions from these two models are similar and generally agree with the available data, suggesting that 1-step DWBA is sufficient to describe the reaction process. Only at a beam energy of 25 MeV there are possibly signs that a 1-step assumption is not fully correct. This work provides motivation for the quantification of uncertainties associated with the transition operator in three-body model. It also suggests that further constraint of the optical potential parameters is needed for increased model precision.

   ↳ nucl-thnucl-exPRC(2024)·11 citations
3. 03*

   Multiscale physics of atomic nuclei from first principles

   Z. H. Sun🇺🇸 · A. Ekström🇸🇪 · C. Forssén🇸🇪 · G. Hagen🇺🇸 · G. R. Jansen🇺🇸 · T. Papenbrock🇺🇸

   Atomic nuclei exhibit multiple energy scales ranging from hundreds of MeV in binding energies to fractions of an MeV for low-lying collective excitations. As the limits of nuclear binding is approached near the neutron- and proton driplines, traditional shell-structure starts to melt with an onset of deformation and an emergence of coexisting shapes. It is a long-standing challenge to describe this multiscale physics starting from nuclear forces with roots in quantum chromodynamics. Here we achieve this within a unified and non-perturbative framework that captures both short- and long-range correlations starting from modern nucleon-nucleon and three-nucleon forces from chiral effective field theory. The short-range correlations which accounts for the bulk of the binding energy is included within a symmetry-breaking framework, while long-range correlations (and fine details about the collective structure) are included via symmetry projection. Our calculations accurately reproduce available experimental data for low-lying collective states and the electromagnetic quadrupole transitions in ${}^{20-30}$Ne. We also reveal coexisting spherical and deformed shapes in ${}^{30}$Ne, which indicates the breakdown of the magic neutron number $N=20$ as the key nucleus ${}^{28}$O is approached, and we predict that the dripline nuclei ${}^{32,34}$Ne are strongly deformed. By developing reduced-order-models for symmetry-projected states, we perform a global sensitivity analysis and find that the subleading singlet S-wave contact and a pion-nucleon coupling strongly impact nuclear deformation in chiral effective-field-theory. The techniques developed in this work clarify how microscopic nuclear forces generate the multiscale physics of nuclei spanning collective phenomena as well as short-range correlations and allow to capture emergent and dynamical phenomena in finite fermion systems.

   ↳ nucl-thnucl-exPRX(2025)·71 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.