Nuclear Theory·nucl-th

Tuesday·July 1, 2025

15 papers—6 primary·9 cross-listed

01
Suppression of genuine tripartition in heavy nuclei: A self-consistent perspective
Yannen Jaganathen · Janusz Skalski
We investigate the ternary fissions of $^{252}$ Cf (spontaneous) and $^{236}$ U (neutron-induced) into medium-mass fragments, as reported by the Dubna group, using the Hartree-Fock plus BCS method with the SLy6 Skyrme interaction. Compared to microscopic-macroscopic methods used so far, this self-consistent approach provides a greater flexibility of nuclear shapes. Our working hypothesis is that the shape evolution proceeds while the system is still mononuclear. The results show that a ternary fission valley emerges for intermediate elongations of the middle fragment, only when its mass is strongly constrained. This ternary mode is dynamically suppressed by the competition with the dominant binary decay channel. This suggests that a description based solely on quantum tunneling through the energy barrier is insufficient to evaluate its probability. To quantify this suppression, we apply a simple Langevin-type model of overdamped motion with constant damping and temperature, supplemented by a basic estimate of quantum tunneling where relevant. Under assumptions expected to yield an upper bound, we find the probability of ternary fission per binary decay to be on the order of $1 0^{- 8} - 1 0^{- 9}$ for $^{252}$ Cf and $1 0^{- 10} - 1 0^{- 11}$ for $^{236}$ U.
nucl-thPLB(2025)·2 citations
02
Quark Phase Space Distributions in Nuclei
Alexis Nikolakopoulos🇺🇸 · Gerald A. Miller🇺🇸
In [PRC 110, 025201], the authors construct a model for nuclear matter which features a quarkyonic phase. A main feature in this model is that the nucleon occupation is strongly reduced at small momenta. Somewhat surprisingly, this result is supported by data for electron scattering from nuclear matter, where a reduction of the cross section consistent with suppression of nucleons with small momenta is seen. Since nuclear matter data are obtained by extrapolation of electron scattering data on increasingly heavier systems, this feature should manifest at least to some degree in heavy nuclei. To check if this is plausible we extend the approach of [PRC 110, 025201] to finite nuclei by considering the nuclear Wigner distribution. We use non-relativistic and relativistic independent particle models to determine the nuclear Wigner distribution, in addition to the local-density approximation (LDA). Phase-space distributions of quarks are obtained as a convolution of the Wigner distribution with a quark momentum distribution. We highlight some properties of the Wigner distribution in spherical systems, which can spoil the interpretation of the quark phase-space distribution as occupation numbers in the Fermi sea. On the other hand, we show that large systems behave essentially like infinite nuclear matter in their interior, and that LDA and full results are quantitatively similar for large A. We then compute the fraction of baryons that would be in a quarkyonic phase in the same sense as in [PRC 110, 025201] for a set of nuclei with mass $12 \leq A \leq 238$ . We find that this fraction systematically tends to a constant at large $A$ . It is hence plausible that the suppression seen in the nuclear matter data is a genuine feature, present in large finite nuclei. This result is counter-intuitive and we discuss possible electron scattering measurements that could rule out this model.
nucl-thPRC(2025)·3 citations
03
Elliptic flow of charged hadrons in d+Au collisions at $s_{N N} =$ 200 GeV using a multi-phase transport model
Jaideep Tanwar🇮🇳 · Ishu Aggarwal🇮🇳 · Vipul Bairathi🇮🇳 · Lokesh Kumar🇨🇱 · Sonia Kabana🇨🇱
This study presents a comprehensive analysis of the elliptic flow coefficient, $v_{2}$ , for charged hadrons at mid-rapidity in d+Au collisions at $s_{NN} = 200 GeV$ . Utilizing the AMPT model in both default and string melting modes, we examine the dependence of $v_{2}$ on transverse momentum, collision centrality, and particle type. Furthermore, we present $v_{2}$ scaled by participant eccentricity, which indicates a similar level of collectivity across different centrality intervals in d+Au collisions at $s_{NN} = 200 GeV$ within the AMPT-SM model. Our results indicate that the early-stage partonic phase significantly influences $v_{2}$ , as observed by variations in parton scattering cross-section, while the later stage hadronic rescattering shows minimal impact. Comparisons with STAR and PHENIX experimental data show that the AMPT model effectively captures the transverse momentum dependence of $v_{2}$ , underlining the importance of parton scattering mechanisms and the need for careful interpretation of experimental results in asymmetric systems.
nucl-thhep-phnucl-exPRC(2026)·0 citations
04
On energy-dependent scaling factor for the charge-changing cross sections of light elements
Z. Hasan · M. Imran · A. A. Usmani · Z. A. Khan
In this study, the scaling factor for $^{28}$ \rm Si + $^{12}$ \rm C charge-changing cross sections (CCCSs) at 90-1296 MeV/nucleon has been used as a basis to introduce the energy dependence in the scaling factor for the light elements. To test the extracted scaling factor, we predict the charge-changing cross sections for $^{7, 9 - 12, 14}$ \rm Be, $^{10 - 15, 17}$ \rm B, $^{11 - 19}$ \rm C, $^{13 - 22}$ \rm N, $^{15 - 24}$ \rm O, and $^{18 - 21, 23 - 26}$ \rm F isotopes at 200-991 MeV/nucleon in the framework of the Glauber model. The calculations use descriptions of nuclei in terms of the Slater determinant involving harmonic oscillator single-particle wave functions, which reproduce the charge radii obtained earlier [Phys. Rev. C {\bf 110} (2024) 014623; {\bf 111} (2025) 064601]. It is found that the theoretical results provide quite a satisfactory explanation of the experimental data in all the cases, and the extracted scaling factor shows systematic energy dependence for the isotopes of a given element. In conclusion, we expect that the present way of finding the scaling factor could be successfully used in the analysis of CCCSs for the elements Z $\leq$ 9 at any desired energy in the range 90-1296 MeV/nucleon. This result may further add that the present work provides a practical scheme for predicting the charge-changing cross sections (and inferring proton radii) of \rm Be-\rm F isotopes, where measurements are scarce.
nucl-thNPA(2026)·1 citation
05
Quarks in Hadrons and Nuclei Part 1: Quark Structure of Nucleon
G. Musulmanbekov🇷🇺
We propose a semi-empirical quark model of nucleon structure, so-called, Strongly Correlated Quark Model, SCQM, which possess the features of both non-relativistic and relativistic quark models. Based on SU(3) color symmetry it includes the main features of QCD: local gauge invariance, asymptotic freedom, and chiral symmetry breaking. This First Part of the paper is devoted to description of the model, SCQM, and in the forthcoming Second Part we will apply the model to built the nuclear structure. Applied to nuclei, it reveals emergence of the face-centered cubic (FCC) symmetry of the nuclear structure.This symmetry arise from quark-quark correlations leading, in turn, to nucleon-nucleon correlations.
nucl-th0 citations
06
Half-life of $^{136}$ Xe for neutrinoless double- $β$ decay calculated with effective axial-vector current coupling unified for two-neurtino and neutrinoless double- $β$ decay modes
J. Terasaki🇨🇿 · O. Civitarese🇦🇷
The upper limit on the mass of the Majorana neutrino, extracted from the limits on the nonobservation of the neutrinoless double- $β$ ( $0 ν β β$ ) decay, is hampered by uncertainties in the matrix elements of the transition operators. Recently, we have shown that the values of the effective axial-vector current coupling constants ( $g_{A}^{eff}$ ) for the $0 ν β β$ and the two-neutrino double- $β$ decays are close. This striking result was obtained for the first time by including vertex corrections and two-body currents in these matrix elements. In this letter, we calculate the half-life for the $0 ν β β$ decay ( $T_{1/2}^{0 ν}$ ) of $^{136}$ Xe using this closeness and show the convergence of the half-life with respect to the variation of the method to determine $g_{A}^{eff}$ . The closeness of the $g_{A}^{eff}$ of the two decay modes plays a decisive role in predicting $T_{1/2}^{0 ν}$ . The appropriate value of $g_{A}^{eff}$ depends on the assumptions made for the sectors of the nuclear structure and transition operators of the calculations within the perturbation scheme. The value $g_{A}^{eff} \approx 1$ is obtained when the SkM $^{*}$ is used to describe the nuclear structure component, while a smaller value of $g_{A}^{eff}$ is obtained by applying a less realistic interaction like the SGII one.
nucl-thnucl-exPRC(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Suppression of genuine tripartition in heavy nuclei: A self-consistent perspective

Quark Phase Space Distributions in Nuclei

Elliptic flow of charged hadrons in d+Au collisions at sNN​​= 200 GeV using a multi-phase transport model

On energy-dependent scaling factor for the charge-changing cross sections of light elements

Quarks in Hadrons and Nuclei Part 1: Quark Structure of Nucleon

Half-life of 136Xe for neutrinoless double-β decay calculated with effective axial-vector current coupling unified for two-neurtino and neutrinoless double-β decay modes

Affiliations

Elliptic flow of charged hadrons in d+Au collisions at $s_{N N} =$ 200 GeV using a multi-phase transport model

Half-life of $^{136}$ Xe for neutrinoless double- $β$ decay calculated with effective axial-vector current coupling unified for two-neurtino and neutrinoless double- $β$ decay modes