Nuclear Theory·nucl-th

Tuesday·April 7, 2026

16 papers—9 primary·7 cross-listed

01
Phenomenological Criteria of Halo Nuclei in Ne Isotopes via Diffuseness and Helm-Model Approaches with Reaction Cross Sections
Heesung Kwon · Kyoungsu Heo · Seonghyun Kim · Eunja Ha · Myung-Ki Cheoun
We present a systematic study of halo characteristics in the neutron-rich isotopes 28-32Ne within the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). Microscopic density distributions are analyzed in coordinate space, momentum space, and reaction observables to establish a quantitative and locally defined criterion for halo identification in medium-mass nuclei. The DRHBc densities reveal a pronounced neutron extension in 31Ne. A phenomenological analysis based on deformed Woods-Saxon fits shows a clear isotopic anomaly in the surface diffuseness parameter, with a value of about 1.1 fm for 31Ne, significantly larger than those of neighboring isotopes. The anomalously large diffuseness is therefore treated as the primary phenomenological halo signature, whereas the reduced fitted radius parameter is used only as a supporting consequence of the chosen normalization and tail-sensitive fit. Helm-model form-factor analysis demonstrates that deformation contributes to geometric smearing but does not fully account for the extended spatial structure, as reflected in the enhanced difference between microscopic and folded rms radii. Glauber reaction cross section calculations further confirm a robust relative enhancement of the interaction cross section for 31Ne that persists across reasonable nucleon-nucleon interaction prescriptions. These complementary analyses consistently identify 31Ne as the most prominent halo candidate within the 28-32Ne isotopic chain, while 32Ne exhibits intermediate features and 29Ne shows no clear halo signature. The present framework provides a practical and quantitative approach for identifying halo phenomena in deformed, neutron-rich nuclei beyond the light-mass region.
nucl-th0 citations
02
Anisotropic Flow of light (anti-)(hyper-)nuclei in Pb+Pb Collision at $s_{N N} = 5.36$ TeV
Fu Ma · Zheng-Qing Wang · Xiong-Hong He · Che Ming Ko · Qi-Ye Shou · Kai-Jia Sun · Wenbin Zhao · Wen-Hao Zhou
Using the coalescence model with nucleon phase-space distributions generated by the hybrid MUSIC framework, we study the elliptic flow ( $v_{2}$ ) and triangular flow ( $v_{3}$ ) of (anti-)protons, (anti-)deuterons, (anti-) $^{3} He$ , and $_{Λ}^{3} H$ in Pb+Pb collisions at $s_{N N} = 5.36$ TeV. We find that the simple $v_{2}$ scaling with the number of constituent nucleons $A$ breaks down at high transverse momentum $p_{T} / A > 1.5$ GeV/ $c$ , while an improved scaling relation holds well up to $p_{T} / A \approx 3$ GeV/ $c$ . In contrast, $v_{3}$ exhibits similar behavior under both scaling prescriptions, with no significant difference. We also make predictions for $v_{2}$ and $v_{3}$ of the hypertriton and find these flows are insensitive to the Lambda-deuteron ( $Λ - d$ ) distance inside the hypertriton. Our results are compared with preliminary experimental measurements by the ALICE Collaboration and offer insight into the production mechanisms of light (anti-)(hyper-)nuclei in high-energy heavy-ion collisions.
nucl-thhep-phPLB(2026)·1 citation
03
Heavy and heavy-light tensor and axial-tensor mesons in the Covariant Spectator Theory
Elmar P. Biernat🇵🇹 · Alfred Stadler🇵🇹
We present the first calculation of tensor and axial-tensor mesons with total spin $J \geq 2$ within the Covariant Spectator Theory. We employ a refined quark-antiquark interaction kernel that incorporates the momentum dependence of the strong coupling, replacing the previously used constant term of the kernel. Global least-squares fits to the masses of experimentally established heavy and heavy-light meson states yield an excellent description of the mass spectrum for $J^{P} = 0^{\pm}, 1^{\pm}, 2^{\pm}$ , and $3^{\pm}$ using only eight adjustable parameters.
nucl-thhep-phActa Phys.Polon.Supp.(2026)·0 citations
04
Disentangling Flow Contributions from the Chiral Magnetic Effect in U+U Collisions with Forward-Backward Multiplicity Asymmetry
Kaiser Shafi🇮🇳 · Sandeep Chatterjee🇮🇳
The observation of the Chiral Magnetic Effect (CME) in heavy-ion collisions remains challenging because of large flow-induced backgrounds and experimental constraints. We demonstrate that the forward-backward multiplicity asymmetry (FBMA) provides a robust and experimentally accessible control parameter to separate the flow background from CME signal in the collisions of deformed nuclei, such as prolate uranium where FBMA is naturally enhanced and correlated with the initial-state geometry. Monte Carlo Glauber simulations indicate that varying FBMA within a fixed centrality class modulates ellipticity largely independently of the magnetic-field correlator, establishing FBMA as a practical tool for disentangling CME signals from flow driven background.
nucl-thhep-phhep-th0 citations
05
Nonlocality Effect in the Alpha decay half-lives of superheavy nuclei with XGBRegressor
Jinyu Hu · Chen Wu
Building on the work of E. L. Medeiros [1] and our previous study [2], we generalize the alpha-nucleus nonlocality effect to odd-A and odd-odd nuclei within the two-potential approach (TPA) framework. The coordinate-dependent parameters introduced by this nonlocality are optimized using an advanced gradient boosting regression model. This improved TPA is applied to calculate the $α$ -decay half-lives of 599 nuclei with $Z = 52 - 118$ , yielding a root-mean-square (RMS) deviation that is 74.8 $%$ lower than that of the original TPA. Subsequently, we employ the improved TPA, along with the DZR [3] and MUDL [4]models, to predict alpha-decay half-lives for 142 superheavy nuclei with $Z = 117 - 120$ . The predictions from all three models are in close agreement, with the results from our improved TPA and the DZR model being nearly identical.
nucl-th0 citations
06
Generation of fission yield covariance matrices and its application in uncertainty analysis of decay heat
Wendi Chen · Tao Ye · Hairui Guo · Jiahao Chen · Bo Yang · Yangjun Ying
The uncertainties and covariance matrices of fission yield are important in the uncertainty analysis of decay heat. At present, there are no covariance matrixes of fission yield given in the evaluated nuclear data library, although they have provided the uncertainties with good estimates. In this work, the generalized least squares (GLS) updating approach was adopted to evaluate the fission yield covariances with the constraints from basic physical conservation equation and chain yield data, using the nuclear data files from ENDF/B-VIII.0, JENDL-5 and JEFF-3.3. Based on these original and updated data, summation calculation was performed for fission pulse decay heat of thermal neutron-induced fission of $^{235}$ U. The uncertainties of decay heat were obtained through generalized perturbation theory, including the uncertainties propagated from fission yield, decay energy, decay constant and branching ratio. The original uncorrelated yield data contributes a $\sim 4%$ uncertainty at all times and dominates the decay heat uncertainty at cooling times longer than \SI{100}{s}. With the generated covariance matrixes, the uncertainty of calculated decay heat is strongly reduced and decay energy data makes a major contribution in general. The relative uncertainties at cooling time \SI{0.1}{\second} are $\sim$ 10 $%$ for ENDF/V-VIII.0 and JEFF-3.3 and $\sim$ 5 $%$ for JENDL-5 and those at cooling time 10 $^{5}$ s are about 1 $%$ for three libraries. The influence of the GLS updating procedure on the contributions of important fission products to decay heat and their sensitive coefficients was also discussed.
nucl-thNucl.Sci.Tech.(2026)·0 citations
07
Dissipative spin hydrodynamics in Bjorken flow and thermal dilepton production
Sejal Singh🇮🇳 · Sourav Dey🇮🇳 · Arpan Das🇮🇳 · Hiranmaya Mishra🇮🇳 · Amaresh Jaiswal🇮🇳
We investigate the boost-invariant expansion of a recently developed first-order spin hydrodynamic framework in which the spin chemical potential is treated as a leading-order hydrodynamic variable. Considering a symmetric energy-momentum tensor and a separately conserved spin tensor, we derive the coupled evolution equations for the medium temperature and the independent components of the spin chemical potential in the presence of both viscous and spin-diffusive transport coefficients. For a boost-invariant system, only the magnetic-like components of the spin chemical potential survive, and their evolution is shown to depend sensitively on the spin transport coefficients. The transverse spin components decay more rapidly due to spin dissipation, while the longitudinal component survives for a longer duration. We further demonstrate that the evolution of the spin degrees of freedom modifies the temperature profile of the expanding medium. Using the resulting temperature profiles, we calculate thermal dilepton production rates from quark-antiquark annihilation. We find that the presence of spin dynamics enhances the dilepton yield relative to standard dissipative hydrodynamics, with the magnitude of the enhancement depending on the spin transport coefficients. Our results indicate that thermal dileptons can provide an indirect probe of spin dynamics and spin transport in the quark-gluon plasma.
nucl-thhep-ph2 citations
08
Rigid triaxiality has the SU(3) symmetry: $^{166}$ Er as an example
Chunxiao Zhou · Xue Shang · Tao Wang
The emergence of triaxiality in the low-lying collective bands of $^{166}$ Er is systematically explored within the SU3-IBM. In this framework, SU(3) higher-order interactions are included, which enable the descriptions of various quadrupole deformations. The triaxiality of $^{166}$ Er is described with a triaxiality angle $γ = 9. 7^{\circ}$ . In addition, the calculated energy spectra, $B (E 2)$ transition strengths, and quadrupole moments show excellent agreement with experimental data. These results provide further evidence supporting the SU(3) triaxial interpretation of $^{166}$ Er and confirm its triaxial deformation rather than the prolate shape.
nucl-th0 citations
09
The Ground State Aspects and the Impact of Shell Structures on the Stability of Es-Isotopes
C. Dash · A. Anupam · I. Naik · B. K. Sharma · B. B. Sahu
In this work, we have analyzed the nuclear structure and several prospective decay characteristics of the $^{240 - 259}$ Es $_{99}$ isotopes. For this we use Relativistic Mean Field model (RMF) with NL-SH and NL3* force parameter in an axially deformed oscillator basis. In structural properties, we have analyzed binding energy (B.E.), skin thickness ( $r_{n p}$ ) , charge radius ( $r_{c}$ ), one neutron separation energy ( $S_{1 n}$ ), two neutron separation energy ( $S_{2 n}$ ), differential variation of two neutron separation energy ( $d S_{2 n}$ ), the single particle energy and its variation with quadrupole deformation parameter of Es isotopes. We have also estimated the $α$ -decay, $β$ -decay and cluster decay half lives of Es isotopes to analyze the shell structure and also to predict the suitable decay mode among them. The $α$ -decay half-life periods are calculated using the MUDL and AKRE formulae using both our calculated Q-values and empirically assessable Q-values. In a similar manner, we have computed the half-lives of cluster decay using Universal Decay Law and HOROI formula. A longer decay half-life indicates a shell stabilized parent nucleus, while a small parent half-life suggests the shell stability of the daughter. This study provides us the insights regarding the structural changes with the change in neutron number enabling us to predict shell closures and nuclear stability. We found a shell/sub-shell closure at N = 154 for the NL-SH parameter set. This research aids in our comprehension of Es isotopes' shell structure and decay mechanism.
nucl-thphysics.soc-phPhys.Scripta(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE