Nuclear Theory·nucl-th

Thursday·December 1, 2022

12 papers—5 primary·7 cross-listed

01
[Submitted on 30 Nov 2022]
Neutron-skin values and matter and neutron radii determined from reaction cross sections of proton scattering on $^{12}$ C, $^{40, 48}$ Ca, $^{58}$ Ni, $^{208}$ Pb
Tomotsugu Wakasa · Shingo Tagami · Jun Matsui · Maya Takechi · Masanobu Yahiro
Very lately, the PREX and the CREX collaboration present skin values, $r_{skin}^{208} (newPREX2) = 0.278 \pm 0.078 (exp) \pm 0.012 (theor.) fm$ and $r_{skin}^{48} = 0.121 \pm 0.026 (exp) \pm 0.024 (model)$ , respectively. We recently determined a neutron-skin value $r_{skin}^{208} = 0.278 \pm 0.035$ fm from measured reaction cross sections $σ_{R} (exp)$ of p+ $^{208}$ Pb scattering in a range of incident energies $10 \lsim E_{in} \lsim 100$ MeV where the chiral (Kyushu) $g$ -matrix folding model is reliable for $^{12}$ C+ $^{12}$ C scattering. The data $σ_{R} (exp)$ are available for proton scattering on $^{58}$ Ni, $^{40, 48}$ Ca, $^{12}$ C targets. Our first aim is to test the Kyushu $g$ -matrix folding model for p+ $^{208}$ Pb scattering in $20 \lsim E_{in} \lsim 180$ MeV. Our second aim is to determine skin values $r_{skin}$ and matter and neutron radii, $r_{m}$ and $r_{n}$ , for $^{208}$ Pb, $^{58}$ Ni, $^{40, 48}$ Ca, $^{12}$ C from the $σ_{R} (exp)$ . Our method is the Kyushu $g$ -matrix folding model with the densities scaled from the D1S-GHFB+AMP densities, where D1S-GHFB+AMP stands for Gogny-D1S HFB (GHFB) with the angular momentum projection (AMP). As for proton scattering, we find that our model is reliable in $20 \lsim E_{in} \lsim 180$ MeV. For $^{208}$ Pb, the skin value deduced from $σ_{R} (exp)$ in $20 \lsim E_{in} \lsim 180$ MeV is $r_{skin}^{208} (σ_{R}) = 0.299 \pm 0.020$ fm. Our results on $r_{skin}$ are compared with the previous works. Our result $r_{skin}^{208} (σ_{R}) = 0.299 \pm 0.020$ fm agrees with $r_{skin}^{208} (PREX2) = 0.283 \pm 0.071$ fm. In addition, our result $r_{skin}^{48} = 0.103 \pm 0.022$ fm is consistent with the CREX value.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2211.16688 [pdf]
PRC(2023)·9 citations
02
[Submitted on 30 Nov 2022]
Medium Response and Jet-Hadron Correlations in Relativistic Heavy-Ion Collisions
Shanshan Cao🇨🇳 · Guang-You Qin🇨🇳
High-energy heavy-ion collisions at the Relativistic Heavy-Ion Collider and the Large Hadron Collider have evolved from qualitative understanding into precise extraction of the properties of the Quantum Chromodynamics medium at extremely high temperature. Jet quenching has offered unique insights into the transport properties of the Quark-Gluon Plasma (QGP) created in these energetic collisions. Apart from medium modification of jets, jet-induced medium excitation constitutes another crucial aspect of jet-QGP interaction, and is indispensable in understanding the soft components of jets. We review recent theoretical and phenomenological developments on medium response to jet energy loss, including an overview of both weakly and strongly coupled approaches for describing the thermalization and propagation of energy deposition from jets, effects of medium response on jet observables, and exploration of its unique signatures in jet-hadron correlations. Jet-induced medium excitation is shown to be an essential component in probing the in-medium dynamics of jets and a critical step towards precise extraction of the QGP properties.
Comments:
25 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2211.16821 [pdf]
Ann.Rev.Nucl.Part.Sci.(2023)·39 citations
03
[Submitted on 30 Nov 2022]
Lifetime of the hypertriton
D. Gazda🇨🇿 · A. Pérez-Obiol🇪🇸 · A. Gal🇮🇱 · E. Friedman🇮🇱
Conflicting values of the hypertriton lifetime $τ (_{Λ}^{3} H)$ were derived in relativistic heavy ion (RHI) collision experiments over the last decade. A very recent ALICE Collaboration measurement is the only experiment where the reported $τ (_{Λ}^{3} H)$ comes sufficiently close to the free- $Λ$ lifetime $τ_{Λ}$ ,as expected naively for a very weakly bound $Λ$ in $_{Λ}^{3} H$ . We revisited theoretically this $_{Λ}^{3} H$ lifetime puzzle, using $_{Λ}^{3} H$ and $^{3} He$ wave functions computed within the abinitio no-core shell model employing interactions derived from chiral effective field theory to calculate the two-body decay rate $Γ (_{Λ}^{3} H \to^{3} He + π^{-})$ . We found significant but opposing contributions arising from $Σ N N$ admixtures in $_{Λ}^{3} H$ and from $π^{-} -^{3} He$ final-state interaction. To derive $τ (_{Λ}^{3} H)$ , we evaluated the inclusive $π^{-}$ decay rate $Γ_{π^{-}} (_{Λ}^{3} H)$ by using the measured branching ratio $Γ (_{Λ}^{3} H \to^{3} He + π^{-}) / Γ_{π^{-}} (_{Λ}^{3} H)$ and added the $π^{0}$ contributions through the $Δ I = \frac{1}{2}$ rule. The resulting $τ (_{Λ}^{3} H)$ varies strongly with the rather poorly known $Λ$ separation energy $E_{sep} (_{Λ}^{3} H)$ and it is thus possible to associate each one of the distinct RHI $τ (_{Λ}^{3} H)$ measurements with its own underlying value of $E_{sep} (_{Λ}^{3} H)$ .
Comments:
Invited talk given at the 14th International Conference on Hypernuclear and Strange Particle Physics (HYP2022), Prague, Czech Republic, June 27 - July 1, 2022. A slightly updated version of the published proceedings contribution
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2211.17122 [pdf]
EPJ Web Conf.(2022)·1 citation
04
[Submitted on 30 Nov 2022]
Predicting Beta Decay Energy with Machine Learning
Jose M. Munoz · Serkan Akkoyun · Zayda P. Reyes · Leonardo A. Pachon
$Q_{β}$ represents one of the most important factors characterizing unstable nuclei, as it can lead to a better understanding of nuclei behavior and the origin of heavy atoms. Recently, machine learning methods have been shown to be a powerful tool to increase accuracy in the prediction of diverse atomic properties such as energies, atomic charges, volumes, among others. Nonetheless, these methods are often used as a black box not allowing unraveling insights into the phenomena under analysis. Here, the state-of-the-art precision of the $β$ -decay energy on experimental data is outperformed by means of an ensemble of machine-learning models. The explainability tools implemented to eliminate the black box concern allowed to identify uncertainty and atomic number as the most relevant characteristics to predict $Q_{β}$ energies. Furthermore, physics-informed feature addition improved models' robustness and raised vital characteristics of theoretical models of the nuclear structure.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Data Analysis, Statistics and Probability (physics.data-an)
arXiv:
2211.17136 [pdf]
PRC(2023)·14 citations
05
[Submitted on 30 Nov 2022]
Vortex rings in heavy-ion collisions at energies $s_{N N} =$ 3--30 GeV and possibility of their observation
Yu. B. Ivanov🇷🇺
The ring structures that appear in Au+Au collisions at collision energies $s_{N N} =$ 3 -- 30 GeV are studied. The calculations are performed within the model of three-fluid dynamics. It is demonstrated that a pare of vortex rings are formed, one at forward and another at backward rapidities, in ultra-central Au+Au collisions at $s_{N N} >$ 4 GeV. The vortex rings carry information about early stage of the collision, in particular about the stopping of baryons. It is shown that these rings can be detected by measuring the ring observable $R_{Λ}$ even in rapidity range $0 < y < 0.5$ (or $- 0.5 < y < 0$ ) on the level of 0.5--1.5\% at $s_{N N} =$ 5 -- 20 GeV. At forward/backward rapidities, the $R_{Λ}$ signal is expected to be stronger. Possibility of observation of the vortex-ring signal against background of non-collective transverse polarization is discussed.
Comments:
7 pages, 5 figures, version published in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2211.17190 [pdf]
PRC(2023)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE

Neutron-skin values and matter and neutron radii determined from reaction cross sections of proton scattering on 12C, 40,48Ca, 58Ni, 208Pb

Medium Response and Jet-Hadron Correlations in Relativistic Heavy-Ion Collisions

Lifetime of the hypertriton

Predicting Beta Decay Energy with Machine Learning

Vortex rings in heavy-ion collisions at energies sNN​​= 3--30 GeV and possibility of their observation

Affiliations

Neutron-skin values and matter and neutron radii determined from reaction cross sections of proton scattering on $^{12}$ C, $^{40, 48}$ Ca, $^{58}$ Ni, $^{208}$ Pb

Vortex rings in heavy-ion collisions at energies $s_{N N} =$ 3--30 GeV and possibility of their observation