Nuclear Theory·nucl-th

Monday·November 18, 2024

9 papers—2 primary·7 cross-listed

01
Exploring the interplay of helicity and global-frame spin density matrix elements
Gavin Wilks🇺🇸 · Zhenyu Ye🇺🇸
A significant $ϕ$ -meson global spin alignment ( $ρ_{00}$ ) signal was measured in Au+Au collisions at $s_{N N} \leq 62$ GeV. Conventional physics mechanisms such as $s (s ˉ)$ spin polarization fail to accommodate this $ρ_{00}$ signal, motivating further investigation into its origin. Recent studies from a general framework utilizing the gauge/gravity duality predict that there could be non-zero helicity-frame spin alignment generated by the relative motion of $s s ˉ$ pairs to the thermal background in heavy-ion collisions, leading to significant global $ρ_{00}$ . In this work, we derive the expected relationships between $ϕ$ -meson helicity and global-frame spin density matrix elements and confirm these analytical results using Monte Carlo simulations. The effects on these relationships from finite elliptic flow and various kinematic selections are also examined. Additionally, we extract $ρ_{00}$ simultaneously with the off-diagonal elements from the 2-dimensional $θ^{*}$ and $β$ angular dimensions, as opposed to the standard 1-dimensional extraction of $ρ_{00}$ . These angles describe the direction of a daughter kaon's momentum in the $ϕ$ -meson's rest frame, where $θ^{*}$ is the polar angle with respect to the chosen spin-quantization axis, and $β$ is the azimuthal angle in the perpendicular plane. This 2-dimensional method allows us to consider possible effects from finite geometric acceptance and detector efficiencies, which could couple to the spin density matrix elements and influence the extraction of these elements within the same frame. The studies presented in this work explore the relationships between helicity and global-frame spin density matrix elements and possible detector effects on the 2-dimensional extraction of spin density matrix elements.
nucl-th1 citation
02
Properties of a kaon-condensed phase in hyperon-mixed matter with three-baryon forces
Takumi Muto🇯🇵
Coexistent phase of kaon condensates and hyperons [( $Y$ + $K$ ) phase] in beta equilibrium with electrons and muons is investigated as a possible form of dense hadronic phase with multi-strangeness. The effective chiral Lagrangian for kaon-baryon and kaon-kaon interactions is utilized within chiral symmetry approach in combination with the interaction model between baryons. For the baryon-baryon interactions, we adopt the minimal relativistic mean-field theory with exchange of scalar mesons and vector mesons between baryons without including the nonlinear self-interacting meson field terms. In addition, the universal three-baryon repulsion and the phenomenological three-nucleon attraction are introduced as density-dependent effective two-body potentials. The repulsive effects leading to stiff equation of state at high densities consist of both the two-baryon repulsion via the vector-meson exchange and the universal three-baryon repulsion. Interplay of kaon condensates with hyperons through chiral dynamics in dense matter is clarified, and resulting onset mechanisms of kaon condensation in hyperon-mixed matter and the equation of state with the ( $Y$ + $K$ ) phase and characteristic features of the system are presented. It is shown that the slope $L$ of the symmetry energy controls the two-baryon repulsion beyond the saturation density and resulting stiffness of the equation of state. The stiffness of the equation of state in turn controls admixture of hyperons and the onset and development of kaon condensates as a result of competing effect between kaon condensates and hyperons. The equation of state with the ( $Y$ + $K$ ) phase becomes stiff enough to be consistent with recent observations of massive neutron stars. Static properties of neutron stars with the ( $Y$ + $K$ ) phase are discussed.
nucl-thastro-ph.HEPRC(2025)·7 citations
03
Efficient Quantum Simulation of QCD Jets on the Light Front
Wenyang Qian🇪🇸 · Meijian Li🇪🇸 · Carlos A. Salgado🇪🇸 · Michael Kreshchuk🇺🇸
Quark and gluon jets provide one of the best ways to probe the matter produced in ultrarelativistic high-energy collisions, from cold nuclear matter to hot quark-gluon plasma. In this work, we propose a unified framework for efficient quantum simulation of many-body dynamics using the (3+1)-dimensional QCD Hamiltonian on the light front, particularly suited for studying the scattering of quark and gluon jets on nuclear matter in heavy-ion collisions. We describe scalable methods for mapping physical degrees of freedom onto qubits and for simulating in-medium jet evolution. We then validate our framework by implementing an algorithm that directly maps second-quantized Fock states onto qubits and uses Trotterized simulation for simulating time dynamics. Using a classical emulator, we investigate the evolution of quark and gluon jets with up to three particles in Fock states, extending prior studies. These calculations enable the study of key observables, including jet momentum broadening, particle production, and parton distribution functions.
↳ hep-phnucl-thquant-phPRD(2025)·23 citations
04
$^{11}$ B states above the $α$ -decay threshold studied via $^{10}$ B $(d, p)^{11}$ B
A.N. Kuchera · G. Ryan · G. Selby · D. Snider · S. Anderson · S. Almaraz-Calderon · L.T. Baby · B.A. Brown · K. Hanselman · E. Lopez-Saavedra · K.T. Macon · G.W. McCann and 3 other authors
The resonance region of $^{11}$ B covering excitation energies from 8.4 MeV to 13.6 MeV was investigated with the $(d, p)$ reaction performed on an enriched $^{10}$ B target at the Florida State University Super-Enge Split-Pole Spectrograph of the John D. Fox Superconducting Linear Accelerator Laboratory. Complementary measurements were performed with a target enriched in $^{11}$ B to identify possible $^{12}$ B contaminants in the $(d, p)$ reaction. Four strongly populated $^{11}$ B states were observed above the $α$ -decay threshold. Angular distributions were measured and compared to DWBA calculations to extract angular momentum transfers and $^{10} B (3^{+}) + n$ spectroscopic factors. The recently observed and heavily discussed resonance at 11.4 MeV in $^{11}$ B was not observed in this work. This result is consistent with the interpretation that it is predominantly a $^{10} Be (0^{+}) + p$ resonance with a possible additional $^{7} Li + α$ contribution. The predicted $^{10} B (3^{+}) + n$ resonance at 11.6 MeV, analogous to the 11.4-MeV proton resonance, was not observed either. Upper limits for the $^{10} B (3^{+}) + n$ spectroscopic factors of the 11.4-MeV and 11.6-MeV states were determined. In addition, supporting configuration interaction shell model calculations with the effective WBP interaction are presented.
↳ nucl-exnucl-thPRC(2024)·1 citation
05
Proton removal from $^{73, 75}$ Br to $^{72, 74}$ Se at intermediate energies
M. Spieker · D. Bazin · S. Biswas · P.D. Cottle · P.J. Farris · A. Gade · T. Ginter · S. Giraud · K.W. Kemper · J. Li · S. Noji · J. Pereira and 4 other authors
We report new experimental data for excited states of $^{72, 74}$ Se obtained from proton removal from $^{73, 75}$ Br secondary beams on a proton target. The experiments were performed with the Ursinus-NSCL Liquid Hydrogen Target and the combined GRETINA+S800 setup at the Coupled Cyclotron Facility of the National Superconducting Cyclotron Laboratory at Michigan State University. Within uncertainties, the inclusive cross sections for proton removal from $^{73, 75}$ Br on a proton target are identical suggesting that the same single-particle orbitals contribute to the proton-removal reaction. In addition, details of the partial cross section fragmentation are discussed. The data might suggest that $l = 1, 2, 3$ , and 4 angular momentum transfers are important to understand the population of excited states of $^{72, 74}$ Se in proton removal. Available data for excited states of $^{74}$ Ge populated through the $^{75}$ As $(d,^{3} He)^{74}$ Ge proton-removal reaction in normal kinematics suggest indeed that the $f p$ and $s d$ shell as well as the $1 g_{9/2}$ orbital contribute. A comparison to data available for odd- $A$ nuclei supports that the bulk of the spectroscopic strengths could be found at lower energies in the even-even Se isotopes than in, for instance, the even-even Ge isotopes. In addition, the population of high- $J$ states seems to indicate that multi-step processes contribute to proton-removal reactions at intermediate energies in these collective nuclei.
↳ nucl-exnucl-thPRC(2024)·1 citation
06
The hyperfine anomaly in mercury and test of the Moskowitz-Lombardi rule
J. Vandeleur · G. Sanamyan · B. M. Roberts · J. S. M. Ginges
The Moskowitz-Lombardi rule gives a simple relation between the magnetic moment of an atomic nucleus and the effect of its radial distribution on the hyperfine structure - the magnetic hyperfine anomaly or "Bohr-Weisskopf" effect. It was originally formulated for mercury, for which experimental data for nuclear magnetic moments and hyperfine constants were available for a number of isotopes. While the relation for the differential effect between isotopes may be completely determined experimentally, the value for the additive constant that is needed to give the Bohr-Weisskopf (BW) effect for a single isotope has remained untested. In this work, we determine the BW effect in singly-ionized and neutral mercury from experimental muonic Hg-199 data together with our atomic calculations. We check this result by directly extracting the BW effect from the hyperfine constant for singly-ionized Hg-199 using state-of-the-art atomic many-body calculations. From this we deduce an empirical value for the additive constant in the Moskowitz-Lombardi rule, which differs significantly from the values advocated previously.
↳ physics.atom-phnucl-exnucl-thPRA(2025)·0 citations
07
Effect of Coriolis Force on Diffusion of D Meson
Ashutosh Dwibedi🇮🇳 · Nandita Padhan🇮🇳 · Dani Rose J Marattukalam🇮🇳 · Arghya Chatterjee🇮🇳 · Sudipan De🇮🇳 · Sabyasachi Ghosh🇮🇳
We have attempted to calculate and estimate the spatial diffusion coefficients of D meson through rotating hadron resonance gas, which can be produced in the late stage of peripheral heavy ion collisions. Employing the framework of kinetic theory in relaxation time approximation, and using Einstein's diffusion relation, one can express the spatial diffusion coefficients of D meson as a ratio of its conductivity to its susceptibility. Here, we have tuned D meson relaxation time from the knowledge of earlier works on its spatial diffusion estimations, and then we have extended the framework for the finite rotation picture of hadronic matter, where only the effect of Coriolis force is considered. Our study also revealed the anisotropic nature of diffusion in the presence of rotation with future possibilities of phenomenological signature.
↳ hep-phhep-exnucl-thJ.Phys.G(2025)·5 citations
08
Photon polarization tensor at finite temperature and density in a magnetic field
Kenji Fukushima🇯🇵 · Yoshimasa Hidaka🇯🇵 · Tomoya Uji🇯🇵
We present analytical and numerical calculations for the photon polarization tensor at finite temperature and density in a constant magnetic field. We first discuss the tensor decomposition in the presence of the magnetic field, which breaks rotational symmetry. Then, we analytically perform all the momentum integrations and numerically take the Landau level sum. We confirm that the imaginary part of the photon polarization tensor correctly reproduces the known result from the independent calculation. We utilize the Kramers-Kronig relation to estimate the real part numerically as a function of the momenta, the chemical potential, and the finite temperature. As an application, we consider the real photon limit and estimate the photon decay rate and the Stokes parameter in the hot and dense medium. We specifically quantify the difference between the X-mode and the O-mode with the polarization orthogonal and parallel to the magnetic field. As long as the magnetic field is weak, the decay rate of the X-mode photon is larger than that of the O-mode photon, while the O-mode becomes dominant due to the Landau level suppression of the X-mode at a strong magnetic field. We also find that the eigenmodes of the propagating photon change their polarization state with increasing density.
↳ hep-phnucl-thJHEP(2025)·4 citations
09
Dynamic scaling and quenching for heavy quark in the linear expanding medium
Boris Blok (Technion)🇩🇪 · Chang Wu (Technion)🇩🇪
We show that scaling is a good approximation for the energy loss of the heavy quark propagating through linear expanding quark-gluon plasma (QGP), the effective quenching parameter does not depend on quark mass.
↳ hep-phnucl-exnucl-thEPJC(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE