Nuclear Theory·nucl-th

Monday·February 10, 2025

11 papers—6 primary·5 cross-listed

01
Investigating effects of the electrical conductivity of QCD matter on charge-dependent directed flow
Nicholas J. Benoit🇯🇵 · Takahiro Miyoshi🇯🇵 · Chiho Nonaka🇯🇵 · Hiroyuki R. Takahashi🇯🇵
Charge dependent directed flow is an important observable of electromagnetic fields in relativistic heavy-ion collisions. We demonstrate how the difference in charge dependent directed flows between protons and antiprotons is sensitive to the resistivity, inverse of quark-gluon plasma's electric conductivity, over different collision centralities. Our model numerically solves the 3+1D relativistic resistive magneto-hydrodynamic (RRMHD) equations, assuming the electric conductivity to be a scalar. For this work, we focus on symmetric Au + Au collisions at the top RHIC energy of $s = 200$ GeV. We illustrate the time evolution of the electromagnetic fields in our model and connect that to the charge dependent directed flow results. Our results highlight the importance of modeling quark-gluon plasma's electric conductivity for charge dependent observables in relativistic heavy-ion collisions.
nucl-thhep-exhep-phnucl-exPRC(2025)·6 citations
02
Probing properties of nuclear spin-orbit interaction with nucleon spin polarization in intermediate-energy heavy-ion collisions
Jun Xu🇨🇳
The nucleon spin polarization perpendicular to the reaction plane ( $P_{y}$ ) and along the beam direction ( $P_{z}$ ) in Au+Au collisions at the beam energy of 100A MeV with different nuclear spin-orbit interactions has been studied based on a spin- and isospin-dependent Boltzmann-Uehling-Uhlenbeck (SIBUU) transport model. While the spin polarization is weaker with a weaker nuclear spin-orbit coupling as intuitively expected, a density-dependent nuclear spin-orbit coupling enhances the $P_{y}$ at large rapidities and leads to a less negative or large $P_{y}$ at high transverse momenta. The difference in the $P_{y}$ of free neutrons and protons at midrapidities and at small transverse momenta is sensitive to the isospin dependence of the nuclear spin-orbit interaction. While the $P_{z}$ is also affected by the properties of nuclear spin-orbit interaction in some sense, the behavior of the $P_{y}$ serves as a good probe of the strength, density dependence, and isospin dependence of nuclear spin-orbit interaction.
nucl-thhep-exnucl-exPRC(2025)·2 citations
03
A glimpse into an effective world
Luigi Coraggio · Nunzio Itaco
Our contribution aims to celebrate the immeasurable contribution that Tom Kuo has provided to the understanding of the structure of atomic nuclei, and also of the infinite nuclear matter, in terms of the fundamental principles governing the realistic nuclear potential. The authors want to testify Tom Kuo's heritage and impact on their approach to the study of nuclear systems by reviewing some recent findings on the role of the two-body component of shell-model effective $β$ -decay operators. The focus is spotted on the so-called Pauli-blocking effect, that plays a non-negligible role in nuclei characterized by a large number of valence nucleons.
nucl-thnucl-exIJMPE(2025)·1 citation
04
Microscopic description of quadrupole-hexadecapole coupling in radium, thorium, uranium and plutonium isotopes with the Gogny energy density functional
R. Rodriguez-Guzman · L.M. Robledo
The emergence and stability of static hexadecapole deformations as well as the impact in the development of dynamic deformation due to collective motion considering quadrupole-hexadecapole coupling are studied for a selected set of radium, thorium, uranium and plutonium isotopes, using the Gogny Hartree-Fock-Bogoliubov and Generator Coordinate Method frameworks. Sizable hexadecapole deformations are found to play a significant role in the ground and excited states of nuclei in the neighborhood of $^{238}$ U. For each of the studied isotopic chains, it is shown that a region with small negative hexadecapole deformation, just below the neutron magic number $N = 184$ , remains stable once zero-point quadrupole-hexadecapole fluctuations are taken into account. A transition is predicted, with increasing mass number, from a regime in which the quadrupole and hexadecapole degrees of freedom are interwoven to a regime in which they are decoupled, accompanied by an enhanced shape coexistence in the more neutron-rich sectors of the isotopic chains. It is also shown, that quadrupole-hexadecapole configuration mixing brings a nontrivial additional correlation energy gain comparable to the quadrupole correlation energy itself.
nucl-thPRC(2025)·7 citations
05
Nuclear size, electric monopole transitions, and the location of $0_{2}^{+}$ states
B. Maheshwari🇫🇷 · K. Nomura🇯🇵 · P. Van Isacker🇫🇷
The work addresses the isotopic shift of nuclear radii for the even-even $^{36 - 52}$ Ca isotopes using the interacting boson model (IBM) that includes the mixing from normal and intruder configurations. We obtain a good agreement between the calculated and experimental data, particularly for the dip at $^{48}$ Ca. A direct correlation between nuclear size and electric monopole transitions is established to compute the electric monopole transition strengths, $ρ^{2} (E 0)$ . We further study the isotopic shift for the even-even $^{32 - 46}$ Ar and $^{44 - 50}$ Ti isotopes.
nucl-thPRC(2025)·0 citations
06
Collision energy dependence in heavy ion collisions from nonlinear QCD evolution
Heikki Mäntysaari🇫🇮 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Wenbin Zhao🇺🇸
We explore the effects of including the energy dependence determined from evolution equations within the color glass condensate framework on observables in ultra-relativistic heavy-ion collisions. This amounts to integrating the JIMWLK evolution equations into the IP-Glasma model, which is then coupled to viscous relativistic hydrodynamics. This methodology allows for a systematic representation of nuclei at specific Bjorken- $x$ values, which are probed at different center-of-mass energies of the collision and rapidities of final state particles. Comparing to the conventional IP-Glasma model, we find significant effects on multiplicity distributions and particle spectra, especially in smaller collision systems at the highest center of mass energies. Our results highlight the importance of incorporating nonlinear QCD evolution in the description of heavy ion collisions at varying center of mass energies, as the precise extraction of transport coefficients will be affected. This work establishes a robust framework for understanding the quark gluon plasma and nuclear structure at high energy, integrating small- $x$ physics into the initial conditions of heavy-ion collisions.
nucl-thhep-exhep-phnucl-exPRL(2025)·22 citations
07
Establishing the vector-meson-exchange dominance for the short range interactions of light quarks
Bing-Song Zou🇨🇳
I give a brief comment on a recent study revealing the vector meson exchange (VME) dominant for the short range interactions between u/d quarks in the $N N$ , $D_{03}$ , and $D_{30}$ systems. The finding echoes nicely with an earlier study of hadron spectroscopy using a quark model with hidden local symmetry which also favors the VME dominant for the short range interactions of light quarks. The VME dominance for the short range interactions of light quarks gives a natural explanation of the empiric VME dominance for the interactions between hadrons containing light quarks.
↳ hep-phnucl-thSCPMA(2025)·3 citations
08
High-precision direct decay energy measurements of the electron-capture decay of $^{97}$ Tc
Zhuang Ge🇫🇮 · Tommi Eronen🇫🇮 · Vasile Alin Sevestrean🇷🇴 · Marlom Ramalho🇫🇮 · Ovidiu Nitescu🇷🇴 · Stefan Ghinescu🇷🇴 · Sabin Stoica🇷🇴 · Jouni Suhonen🇫🇮 · Antoine de Roubin🇧🇪 · Dmitrii Nesterenko🇫🇮 · Anu Kankainen🇫🇮 · Pauline Ascher🇫🇷 and 18 other authors
A direct measurement of the ground-state-to-ground-state electron-capture decay $Q$ ( $Q_{EC}$ ) value of $^{97}$ Tc has been conducted employing the high resolving power phase-imaging ion-cyclotron-resonance technique with the double Penning trap mass spectrometer JYFLTRAP. The resulting $Q_{EC}$ value for $^{97}$ Tc is 324.82(21) keV, exhibiting a precision approximately 19 times higher than the value adopted in the newest Atomic Mass Evaluation (AME2020) and differing by 1.2 $σ$ . Furthermore, by combining this refined $Q$ value with nuclear energy-level data for the decay-daughter $^{97}$ Mo, a potential ultra-low Q-value transition, possibly of allowed type, $^{97}$ Tc (9/2 $^{+}$ , ground state) $\to$ $^{97}$ Mo $^{*}$ (320(1) keV), was evaluated for future long-term neutrino-mass determination experiments. The ground-state-to-excited-state electron-capture decay $Q$ value ( $Q_{EC}^{*}$ ) of this transition was determined to be 4.8(10) keV, confirming it to be energetically allowed with a confidence level of exceeding 4 $σ$ . The captures of electrons occupying the L and higher shells for this transition are energetically allowed, giving a value of 2.0(10) keV for the closest distance of $Q_{EC}^{*}$ to the allowed binding energy of the L1 shell. To predict partial half-lives and energy-release distributions for this transition, the atomic self-consistent many-electron Dirac--Hartree--Fock--Slater method and the nuclear shell model have been employed. Dominant correction terms such as exchange and overlap corrections, as well as shake-up and shake-off effects, were included in the final results. Moreover, the normalized distribution of released energy in the electron-capture decay of $^{97}$ Tc to excited states of $^{97}$ Mo, is compared with that of $^{163}$ Ho, which is being used for electron-neutrino-mass determination.
↳ nucl-exnucl-thPRC(2025)·2 citations
09
Chiral effective model of cold and dense two-color QCD: The linear sigma model approach
Daiki Suenaga🇯🇵
This review is devoted to summarizing recent developments of the linear sigma model (LSM) in cold and dense two-color QCD (QC $_{2}$ D), in which lattice simulations are straightforwardly applicable thanks to the disappearance of the sign problem. In QC $_{2}$ D, both theoretical and numerical studies derive the presence of the so-called baryon superfluid phase at sufficiently large chemical potential ( $μ_{q}$ ), where diquark condensates govern the ground state. The hadron mass spectrum simulated in this phase shows that the mass of an iso-singlet ( $I = 0$ ) and $0^{-}$ state is remarkably reduced, but such a mode cannot be described by the chiral perturbation theory. Motivated by this fact, I invent the LSM constructed upon the linear representation of chiral symmetry, or more precisely the Pauli-Gürsey symmetry. Then, it is shown that my LSM successfully reproduces the low-lying hadron mass spectrum in a broad range of $μ_{q}$ simulated on the lattice. As applications of the LSM, topological susceptibility and sound velocity in cold and dense QC $_{2}$ D are evaluated to compare with lattice results. Besides, generalized Gell-Mann-Oakes-Renner relation and hardon mass spectrum in the presence of a diquark source are analyzed. I also introduce an extended version of the LSM incorporating spin- $1$ hadrons.
↳ hep-phhep-latnucl-thSymmetry(2025)·10 citations
10
Lattice perspectives on doubly heavy tetraquarks
Anthony Francis🇹🇼
Doubly heavy tetraquarks have emerged as new probes to study the heavy hadron spectrum. With the experimental observation of the $J^{P} = 1^{+}$ $T_{cc}^{+}$ , they pose a unique opportunity to bring together efforts in experiment, phenomenology, and lattice QCD. In lattice calculations they are accessible as ground states, unlike hidden flavor tetraquarks, and this enables accurate determinations of the scattering parameters alongside the binding energies of these tetraquarks. Today, lattice calculations firmly predict $J^{P} = 1^{+}$ $T_{bb}^{u d}$ and $T_{bb}^{u s}$ as QCD bound states, while recent studies approaching the $J^{P} = 1^{+}$ $T_{cc}^{u d}$ find it to be a virtual bound state at slightly non-physical input quark masses. Studies of the $J^{P} = 1^{+}$ $T_{b c}^{u d}$ are ongoing and a new focus area. In light of these developments the evolution of this field until this point is reviewed. Emphasis is put on the methods in lattice spectroscopy that enable a robust evaluation of the lattice studies gathered. They are further reviewed towards their limitations and achievements. Current challenges and opportunities are discussed, including possibilities to approach the left-hand cut in the scattering analysis of the charm candidates and towards understanding the structure of those including two bottom quarks.
↳ hep-lathep-phnucl-thPPNP(2025)·26 citations
11
Speed of sound in Kaluza-Klein Fermi gas
Anna Horváth🇭🇺 · Emese Forgács-Dajka🇭🇺 · Gergely Gábor Barnaföldi🇭🇺
A five-dimensional Kaluza-Klein spacetime model is considered, with one extra compactified spatial dimension. The equation of state of an electrically neutral, zero-temperature Fermi gas with a repulsive linear potential is described. From the equation of state, the speed of sound squared is calculated and shown for different model parameters. Its properties are studied from lower energies up to the conformal limit.
↳ hep-phastro-ph.HEnucl-thActa Phys.Polon.Supp.(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE