Nuclear Theory·nucl-th

Thursday·September 12, 2024

12 papers—5 primary·7 cross-listed

01
Alpha decay law of excited nuclei and its role in stellar decay rates
D. F. Rojas-Gamboa · N. G. Kelkar · O. L. Caballero
$α$ decay is one of the prominent decay modes in the nucleosynthesis of heavy and super-heavy elements synthesized at temperatures of the order of Giga Kelvin. To facilitate the investigation of the role played by the $α$ decay half-lives of thermally excited nuclei in nucleosynthesis calculations, an empirical formula based on a model for the $α$ decay of nuclei in their ground and excited states to daughter nuclei in their ground or excited states is presented. Constants appearing in the analytical expression for the $α$ decay half-life obtained within the model are treated as adjustable parameters and fitted to experimental data on 342 $α$ decays in the range of 82 $\leq Z_{p} \leq$ 94, to obtain an excitation energy-dependent decay law. Under the assumption that thermal equilibrium has been reached between nuclear states, temperature ( $T$ )-dependent half-lives, $t_{1/2} (T)$ , for several of the experimentally studied $α$ emitters with 65 $\leq Z_{p} \leq$ 94 are presented using available data on the half-lives of excited nuclei. Though the general trend is a decrease in $t_{1/2} (T)$ at elevated temperatures, exceptional cases with increased half-lives are found in the case of some isomeric states. A list of such isomers provided in this work motivates future work involving considerations of their thermal equilibration and role in shaping kilonova light curves.
nucl-thastro-ph.SRnucl-exPRC(2024)·5 citations
02
Phase Stability in the 3-Dimensional Open-source Code for the Chiral mean-field Model
Nikolas Cruz-Camacho🇺🇸 · Rajesh Kumar🇺🇸 · Mateus Reinke Pelicer🇺🇸 · Jeff Peterson🇺🇸 · T. Andrew Manning🇺🇸 · Roland Haas🇺🇸 · Veronica Dexheimer🇺🇸 · Jaquelyn Noronha-Hostler🇺🇸
In this paper we explore independently for the first time three chemical potentials (baryon $μ_{B}$ , charged $μ_{Q}$ , and strange $μ_{S}$ ) in the Chiral Mean Field (CMF) model. We designed and implemented \texttt{CMF++}, a new version of the CMF model rewritten in \texttt{C++} that is optimized, modular, and well-documented. \texttt{CMF++} has been integrated into the MUSES Calculation Engine as a free and open-source software module. The runtime improved in more than 4 orders of magnitude across all 3 chemical potentials, when compared to the legacy code. Here we focus on the zero temperature case and study stable, as well as metastable and unstable, vacuum, hadronic, and quark phases, showing how phase boundaries vary with the different chemical potentials. Due to the significant numerical improvements in \texttt{CMF++}, we can now for the first time sweep the entire $μ_{B}$ , $μ_{S}$ , $μ_{Q}$ phase space, investigate metastable phases, and calculate high-order susceptibilities within the CMF framework. This allows us to find phases of matter that include a light hadronic phase, a strangeness-dominated hadronic phase, and a quark phase. The numerical improvements also allow us to identify the order of the transitions among these phases, finding a first-order chiral symmetry restoration phase transition among the hadronic phases (favored for negative $μ_{Q}$ and/or $μ_{S}$ for some coupling schemes), in addition to third-order phase transitions. In particular, we identify for the first time triple points in the CMF model, where both chiral symmetry restoration and deconfinement phase transitions meet in the chemical potential phase space. Such points could potentially be identified in low-energy heavy-ion collisions.
nucl-thastro-ph.HEhep-phPRD(2025)·29 citations
03
Neutron skin and its effects in heavy-ion collisions
Meng-Qi Ding🇨🇳 · De-Qing Fang🇨🇳 · Yu-Gang Ma🇨🇳
Neutron skin is an exotic phenomena in unstable nuclei. The various effects in nuclear reactions caused by the neutron skin and also its relation with the properties of nuclear structure are reviewed in this article. Based on numerous studies with theoretical models, strong correlations have been found between the neutron skin thickness and neutron removal cross section, neutron/proton yield ratio, t/\ch{^3He} yield ratio, neutron-proton momentum difference, isoscaling parameter, photon production, reaction cross sections for neutron induced reactions, charge-changing cross sections difference of mirror nuclei, astrophysical $S$ -factor, and other quantities in nuclear reactions induced by neutron-rich nuclei. Moreover, the relationships between neutron skin thickness and some properties of nuclear structure, such as $α$ -cluster formation, $α$ decay, nuclear surface, nuclear temperature, and proton radii difference of mirror nuclei, have also been investigated. It also has been shown that the neutron skin plays a crucial role in relativistic heavy-ion collisions. Experimentally, an unstable nucleus with neutron skin can be generated by radioactive nuclear beam facilities, and the thickness of neutron skin could be extracted by measuring the sensitive probes, which further helps giving stringent constraints on the equation of state of asymmetric nuclear matter and properties of neutron stars.
nucl-thnucl-exNucl.Sci.Tech.(2024)·29 citations
04
Resummed spin hydrodynamics from quantum kinetic theory
David Wagner🇮🇹
In this work, the equations of dissipative relativistic spin hydrodynamics based on quantum kinetic theory are derived. Employing the inverse-Reynolds dominance (IReD) approach, a resummation scheme based on a power counting in Knudsen and inverse Reynolds numbers is constructed, leading to hydrodynamic equations that are accurate to second order. It is found that the spin dynamics can be characterized by eleven equations: six of them describe the evolution of the components of the spin potential, while the remaining five provide the equation of motion of a dissipative irreducible rank-two tensor. For a simple truncation, the first- and second-order transport coefficients are computed explicitly.
nucl-thPRD(2025)·29 citations
05
Ab initio Green's functions approach for homogeneous nuclear matter
Francesco Marino · Carlo Barbieri · Gianluca Colò · Weiguang Jiang · Samuel J. Novario
Homogeneous nuclear matter is investigated using the \textit{ab initio} Self-consistent Green's function (SCGF) approach with nuclear interactions based on chiral effective field theory. The employed method, which combines the state-of-the-art algebraic diagrammatic construction approximation at third order with Gorkov correlations, is capable of computing both the equation of state (EOS) and single-particle properties of nuclear matter. The EOS calculated with our approach and coupled-cluster theory are shown to agree very well. The one-nucleon spectral functions and the momentum distributions are discussed to gain insights into the dynamics of the interacting nuclear matter.
nucl-thcond-mat.quant-gascond-mat.str-elPoS(2025)·5 citations
06
Baryon stopping and charge deposition in heavy-ion collisions due to gluon saturation
Oscar Garcia-Montero🇩🇪 · Sören Schlichting🇩🇪
We compute baryon and electric charge deposition in high-energy heavy-ion collisions using the Color Glass Condensate (CGC) Effective Field Theory, where at leading order charge is deposited through multiple scatterings of valence quarks with a saturated gluon target. A simplified phenomenological formula is derived to describe charge deposition, from which the parametrical dependence with collisional energy and geometry can be extracted. We present an approximate analytical prediction of the so-called baryon stopping parameter $α_{B}$ , which shows excellent agreement with the state-of-the art extractions of $α_{B}$ from experimental data. These results are further validated using the McDIPPER framework, by computing charge deposition at midrapidity across a range of collision energies ( $s_{NN} = 62.4 - 5020$ GeV).
↳ hep-phnucl-exnucl-thPRC(2025)·9 citations
07
Unified and optimal frame choice for generalized parton distributions
Jian-Wei Qiu🇺🇸 · Nobuo Sato🇺🇸 · Zhite Yu🇺🇸
Reconstructing the internal three-dimensional quark and gluon structures of hadrons through generalized parton distributions (GPDs) from hard exclusive scattering processes is one of the most challenging tasks in nuclear and particle physics. In this paper, we introduce a new optimized reference frame that, for the first time, enables a unified view of all the reactions sensitive to GPDs and facilitates the interpretation of a variety of phase-space patterns that were previously hardly accessible and interpretable. Similarly to how the heliocentric description advanced our understanding of the solar system and gravitation, our new frame centers around a quasireal state, allows for a consistent separation of physical scales, and reveals a novel quantum interference mechanism.
↳ hep-phhep-exhep-latnucl-ex+1PRD(2025)·5 citations
08
Investigations on the equation of state of neutron star matter with density-dependent relativistic mean-field model
Kaixuan Huang🇨🇳 · Jinniu Hu🇨🇳
The compact object with a mass of $2.50 - 2.67 M_{⊙}$ observed by LIGO Scientific and Virgo collaborations in GW190814, as well as the recent report of a light compact object with a mass and radius of $M = 0.7 7_{- 0.17}^{+ 0.20} M_{⊙}$ and $R = 10. 4_{- 0.78}^{+ 0.86}$ km within the supernova remnant HESS J1731-347, have posed a great challenge to the investigations into the supranuclear matter. In the inner core region of the neutron star, the strangeness degrees of freedom, such as the hyperons, can be present, which is also named as a hyperonic star. In this work, the neutron star consisting of nucleons and leptons, and the hyperonic star including the hyperons will be studied in the framework of the density-dependent relativistic mean-field (DDRMF) model. Some popular DDRMF parameterizations will be adopted to investigate the properties of nuclear matter and the mass, radius, tidal deformability, and other properties of neutron star and hyperonic stars. We find that the maximum masses of neutron star calculated by DD-MEX, DD-MEX1, DD-MEX2, DD-MEXY and DD-LZ1 sets can be around $2.5 - 2.6 M_{⊙}$ with quite stiff equations of state (EOSs) generated by their strong repulsive contributions from vector potentials at high densities. Moreover, by investigating the influence of the crust EOS and core EOS on the neutron stars, we find that the observational data from HESS J1731-347 suggest the requirement of a crust EOS with a higher $L$ parameter and a core EOS with a lower $L$ parameter, and the $M - R$ relations from the constructed EOSs can also be consistent with the observables of PSR J0740+6620, PSR J0030+0451 from NICER and the GW170817 event. With the inclusion of hyperons, the hyperonic star matter becomes softer compared to the neutron star matter. But the massive hyperonic star can also be obtained with DDRMF parameter sets if the vector coupling constants are strong.
↳ astro-ph.HEnucl-thNucl.Phys.Rev.(2024)·3 citations
09
Unraveling the Effects of Cluster Transfer-Induced Breakups on $^{12}$ C Fragmentation in Hadron Therapy
Arunima Dev T V · Anagha P. K · Midhun C.V · M.M Musthafa · Vafiya Thaslim T.T · Shaima Akbar · Swapna B · Nicemon Thomas · Antony Joseph · S. Ganesan
The capability of standard Geant4 PhysicsLists to address the fragmentation of $^{12}$ C $-^{12}$ C was assessed through a comparative analysis with experimental cross sections reported by Divay et al. and Dudouet et al. The standard PhysicsLists were found to be inadequate in explaining the fragmentation systematics. To address this limitation, the breakup component of fragmentation was systematically integrated into the standard PhysicsList, which successfully replicated the differential and double differential cross sections for $α$ production. This breakup component was modeled using fresco CDCC-CRC calculations. This novel physics process was then incorporated into the Geant4 framework, facilitating the calculation of dose distributions in water and tissue. The application of this method demonstrated a precise reproduction of the dose deposited at the Bragg peak region, corroborating the experimental data from Liedner et al., thereby enhancing the accurate visibility of dose tailing.
↳ physics.med-phnucl-exnucl-thJ.Subatomic Part.Cosmol.(2026)·2 citations
10
Anisotropic linear waves and breakdown of the momentum expansion in spin magnetohydrodynamics
Zhe Fang🇨🇳 · Koichi Hattori🇨🇳 · Jin Hu🇨🇳
We formulate spin magnetohydrodynamics (MHD) by including the magnetic-flux and total angular momentum conservation laws in the hydrodynamic framework. To specify the local angular momentum conservation, we choose the totally antisymmetric spin current. The entropy-current analysis allows for ten dissipative first-order transport coefficients including anisotropic spin relaxation rates and the conversion rate between a vorticity (shear) to a symmetric stress (antisymmetric torque), as well as anisotropic viscosities and resistivities. By employing the linear-mode analysis, we solve the first-order spin MHD equations to determine the dispersion relations with the complete information of anisotropy retained. Our analytic solutions indicate that the small-momentum expansion is spoiled by blow up of the higher-order terms when the angle between the momentum and the magnetic field approaches the right angle. This also reveals the existence of another expansion parameter, and, in light of it, we provide solutions in an alternative series expression beyond the critical angle. We confirm that these two series expansions work well in the appropriate angle ranges as compared with numerical results. Building on our findings regarding the breakdown of the small-momentum expansion in first-order theory, we proceed to discussing how these first-order solutions are modified when we include the relaxation dynamics for dissipative modes with the Israel-Stewart framework. We find that, due to the presence of the critical behavior in the first-order solutions, there remains a diffusive window even after the relaxation dynamics is introduced.
↳ hep-phnucl-thPRD(2025)·12 citations
11
Phenomenological model for the $γ^{*} γ \to η π^{+} π^{-}$ reaction in the $f_{1} (1285)$ energy region
Xiu-Lei Ren🇩🇪 · Igor Danilkin🇩🇪 · Marc Vanderhaeghen🇩🇪
Motivated by the ongoing analysis by the BESIII Collaboration on the single-tagged $e^{+} e^{-} \to e^{+} e^{-} η π^{+} π^{-}$ reaction, we present a phenomenological study of the diphoton fusion to $η π^{+} π^{-}$ , focusing on the production mechanism of the $f_{1} (1285)$ resonance. Contributions from the $f_{1} (1285) \to a_{0} (980)^{\pm} π^{\mp}$ and $f_{1} (1285) \to σ / f_{0} (500) η$ channels are included without introducing free parameters within an effective Lagrangian approach. Assuming the destructive interference between the amplitudes, we predict the invariant mass distributions, angular distributions, and total cross sections of the $γ^{*} γ \to η π^{+} π^{-}$ process, which will be tested by the forthcoming BESIII measurements.
↳ hep-phhep-exnucl-thPRD(2024)·4 citations
12
$^{61}$ Cr as a Doorway to the N = 40 Island of Inversion
L. Lalanne🇧🇪 · M. Athanasakis-Kaklamanakis🇧🇪 · D. D. Dao🇫🇷 · Á. Koszorús🇧🇪 · Y. C. Liu🇨🇳 · R. Mancheva🇧🇪 · F. Nowacki🇫🇷 · J. Reilly🇬🇧 · C. Bernerd🇨🇭 · K. Chrysalidis🇨🇭 · T. E. Cocolios🇧🇪 · R. P. de Groote🇧🇪 and 15 other authors
This paper reports on the measurement of the ground-state spin and nuclear magnetic dipole moment of $^{61}$ Cr. The radioactive ion beam was produced at the CERN-ISOLDE facility and was probed using high-resolution resonance ionization laser spectroscopy with the CRIS apparatus. The present ground-state spin measurement $I = \frac{1}{2}$ , differing from the previously adopted $I = (\frac{5}{2})$ , has significant consequences on the interpretation of existing beta decay data and nuclear structure in the region. The structure and shape of $^{61}$ Cr is interpreted with state-of-the-art Large-Scale Shell Model and Discrete-Non-Orthogonal Shell Model calculations. From the measured magnetic dipole moment $μ (^{61}$ Cr $) = + 0.539 (7) μ_{N}$ and the theoretical findings, its configuration is understood to be driven by 2 particle - 2 hole neutron excitations with an unpaired $1 p_{1/2}$ neutron. This establishes the western border of the $N = 40$ Island Of Inversion (IoI), characterized by 4 particle - 4 hole neutron components. We discuss the shape evolution along the Cr isotopic chain as a quantum phase transition at the entrance of the $N = 40$ IoI.
↳ nucl-exnucl-thPRC(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE