Nuclear Theory·nucl-th

Monday·March 24, 2025

15 papers—8 primary·7 cross-listed

01
Decays of $N^{*}$ and $Δ^{*}$ resonances into $N ρ$ , $Δ π$ , and $N σ$
A.V. Sarantsev🇩🇪 · E. Klempt🇩🇪 · K.V. Nikonov🇩🇪 · T. Seifen🇩🇪 · U. Thoma🇩🇪 · Y. Wunderlich🇩🇪 · P. Achenbach🇺🇸 · V.D. Burkert🇺🇸 · V. Mokeev🇺🇸 · V. Crede🇺🇸
The decays of $N^{*}$ and $Δ^{*}$ resonances into $N ρ$ , $Δ π$ and $N σ$ final states are studied in a coupled-channel analysis of data on pion- and photo-induced reactions. Improvements in the fit were observed when new resonance contributions were introduced. Frequencies for the intermediate isobars $Δ (1232) π$ , $N ρ$ , $N σ$ are reported.
nucl-thPRC(2025)·8 citations
02
Bayesian reconstruction of anisotropic flow fluctuations at fixed impact parameter
Enak Roubertie🇫🇷 · Mathis Verdan🇫🇷 · Andreas Kirchner🇺🇸 · Jean-Yves Ollitrault🇫🇷
The cumulants of the distribution of anisotropic flow are measured accurately in Pb+Pb collisions at the LHC as a function of centrality classifiers (charged multiplicity and/or transverse energy). Using Bayesian inference, we reconstruct from these measurements the probability distribution of anisotropic flow in the ``theorists' frame'' where the impact parameter has a fixed magnitude and orientation, up to $\sim 70%$ centrality. The variation of flow fluctuations with impact parameter displays direct evidence of viscous damping, which is larger for higher Fourier harmonics, in line with expectations from hydrodynamics. We use intensive measures of non-Gaussian flow fluctuations, which have reduced dependence on centrality. We infer from ATLAS data the magnitude of these intensive non-Gaussianities in each Fourier harmonic. They provide data-driven estimates of response coefficients to initial anisotropies, without resorting to any specific microscopic model of initial conditions. These estimates agree with viscous hydrodynamic calculations.
nucl-thhep-exhep-phnucl-exPRC(2025)·5 citations
03
Many-Body Effects on Nuclear Short Range Correlations
Haoyu Shang · Jiawei Chen · Rongzhe Hu · Xin Zhen · Chongji Jiang · Junchen Pei
We reveal nuclear many-body effects on short range correlations by ab initio no-core shell model calculations of the scaling factor a2. The factor a2 characterizes the abundance of SRC pairs and is linearly related to the EMC effect. Our study employs the fifth-order N4LO chiral nuclear force without softening, enabling to distinguish the influences of nuclear states with different quantum numbers on SRC. It is striking to find that a2 is reduced and close in triplet isobaric analog states of neighboring nuclei, indicating that it is insufficient to estimate SRC abundances by considering only mean-field shell structures. This is explained as specific nuclear states suppress the formation of deuteron-like component, impacting our understandings of the link between high-energy partonic properties and low-energy nuclear physics.
nucl-thPLB(2025)·4 citations
04
Dipole Polarizability of Finite Nuclei as a Probe of Neutron Stars
P.S. Koliogiannis · E. Yuksel · T. Ghosh · N. Paar
Nuclear ground state and collective excitation properties provide a means to probe the nuclear matter equation of state and establish connections between observables in finite nuclei and neutron stars. Specifically, the electric dipole polarizability, measured with high precision in various neutron-rich nuclei, serves as a robust constraint on the density dependence of the symmetry energy. In this Letter, we employ a class of relativistic energy density functionals in a twofold process: first, to link the electric dipole polarizability from recent experiments to the slope of the symmetry energy, and second, to translate this information into constraints on the tidal deformability and radii of neutron stars, in connection with multimessenger astrophysical observations from pulsars and binary neutron stars. We provide compelling evidence that the electric dipole polarizability represents a key nuclear observable to probe the neutron star properties. By significantly reducing the uncertainties in the mass-radius plane, our findings also align with recent multimessenger observations.
nucl-thastro-ph.HEastro-ph.SRnucl-exApJL(2026)·4 citations
05
$β$ -Decay Properties of Neutron-rich Yttrium Isotopes
Fakeha Farooq · Jameel-Un Nabi · Ramoona Shehzadi
In this study, we have reported key nuclear properties of weak $β$ -decay processes on Yttrium isotopes for the mass number range $A = 101 - 108$ . This mass region is important in astrophysical $r$ -process abundances. Our study might be helpful in $r$ -process simulations. We have computed charge-changing strength distributions, $β$ -decay half-lives, $β$ -delayed neutron emission probabilities, and $β^{-}$ (EC) weak rates under stellar conditions. We have performed microscopic calculations based on deformed proton-neutron quasi-particle random phase approximation (pn-QRPA) over a wide temperature ( $1 0^{7} - 3 \times 1 0^{10}$ ) K and density ( $10 - 1 0^{11}$ ) g/cm $^{3}$ domain. Unique first-forbidden (U1F) transitions have been included in the calculations in addition to the allowed transitions. A significant decrease in calculated half-lives in certain cases, e.g., in $^{107}$ Y ( $^{108}$ Y) by about 67\% (42\%), has been observed because of the contribution from U1F transitions. We have compared present results with measured and theoretical works. A good agreement of our half-lives with experimental data is observed.
nucl-thPhys.Scripta(2021)·2 citations
06
Investigation of pairing correlations on computed Gamow-Teller strength distributions and associated $β$ -decay half-lives
Jameel-Un Nabi · Asim Ullah · Muhammad Tahir
We investigate the effect of pairing correlations on the computed Gamow-Teller (GT) strength distributions and corresponding $β$ -decay half-lives. The calculations are performed for a total of 47 sd-shell nuclei, for $20 < A < 30$ , employing the pn-QRPA model. Our calculations use three different values of pairing gaps computed using three different empirical formulae. The GT strength distribution and centroid values change considerably with a change in the pairing gap values. This, in turn, leads to differences in computed half-lives. The pairing gaps computed using the mass-dependent formula result in the calculated half-lives being in better agreement with the measured data.
nucl-thNew Astron.(2022)·0 citations
07
Effect of nuclear deformation on Gamow-Teller strength distributions of Hg isotopes
Jameel-Un Nabi · Muhammad Riaz · Tuncay Bayram · Muhammad Azaz
Recent studies \cite{1,2} predicted the sensitivity of the Gamow-Teller (GT) strength distributions to nuclear deformation in neutron-deficient Hg isotopes. Motivated by this work, we investigate nuclear ground-state properties and GT strength distributions for neutron-deficient Hg isotopes ( $^{177-193}$ Hg). The nuclear deformation ( $β (E 2)$ ) values were calculated using the **Relativistic Mean Field (RMF)** model. The RMF approach, with different density-dependent interactions (**DD-ME2** and **DD-PC1**), was employed to compute nuclear shape parameters. These computed deformation values were then used within the framework of the **deformed proton-neutron quasi-particle random phase approximation (pn-QRPA)** model, with a separable interaction, to calculate the allowed GT strength distributions for these Hg isotopes. Our calculations validate the findings of \cite{1} and confirm the effect of deformation on GT strength distributions. This study may further provide a complementary signature for nuclear shape isomers. Noticeable differences are highlighted between our results and previous calculations. The study of \cite{1} suggests that $^{177-182}$ Hg possess prolate shapes, while $^{184-196}$ Hg exhibit oblate shapes. In contrast, our calculations predict **prolate** shapes for $^{177-188}$ Hg and **oblate** shapes for $^{189-193}$ Hg isotopes.
nucl-thBraz.J.Phys.(2022)·2 citations
08
Linear sigma model with quarks and Polyakov loop in rotation: phase diagrams, Tolman-Ehrenfest law and mechanical properties
Pracheta Singha🇷🇴 · Sergiu Busuioc🇷🇴 · Victor E. Ambrus🇷🇴 · Maxim N. Chernodub🇷🇴
We study the effect of rotation on the confining and chiral properties of QCD using the Polyakov-enhanced linear sigma model coupled to quarks. Working in the homogeneous approximation, we obtain the phase diagram at finite temperature, baryon density and angular frequency, taking into account the causality constraint enforced by the spectral boundary conditions at a cylindrical surface. We explicitly address various limits with respect to system size $R$ , angular frequency $Ω$ and chemical potential $μ$ . We demonstrate that, in this model, the critical temperatures of both the chiral restoration and the deconfinement transitions diminish in response to the increasing rotation, being in contradiction with the first-principle lattice results. We demonstrate that consistency between the thermodynamics of the model and the Tolman-Ehrenfest law is achieved in the limit of large volume. We also compute the mechanical characteristics of the rotating plasma, such as the moment of inertia and the $K_{n}$ shape coefficients describing the response of the thermodynamic potential with respect to the increase of angular velocity $Ω$ .
nucl-thhep-phhep-thPRD(2025)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE