Nuclear Theory·nucl-th

Wednesday·May 15, 2024

16 papers—5 primary·11 cross-listed

01
Relativistic Guiding-Center Motion: Action Principle, Kinetic Theory, and Hydrodynamics
Dam Thanh Son · Mikhail Stephanov
We treat the guiding-center dynamics in a varying external Maxwell field using a relativistically covariant action principle which reproduces the known Vandervoort expression for the drift velocity and extends it to curved spacetime. We derive the corresponding kinetic theory and ideal hydrodynamic theory. In contrast to conventional five-equation hydrodynamics, the guiding-center hydrodynamics needs only three equations due to a constraint on the motion across magnetic field. We argue that such a hydrodynamics is applicable to strongly coupled plasmas where kinetic theory fails.
nucl-thastro-ph.HEhep-thphysics.plasm-phPRL(2024)·2 citations
02
Possible explanation of the irregular energy dependence of the rapidity width of $ϕ$ mesons observed in Pb+Pb collisions
Tom Reichert🇩🇪 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
Experimental data from the NA49 collaboration show an unexpectedly steep rise of the rapidity width of the $ϕ$ meson as function of beam energy, which was suggested as possible interesting signal for novel physics. In this work we show that the Ultra-relativistic Quantum-Molecular-Dynamics (UrQMD) model is able to reproduce the shapes of the rapidity distributions of most measured hadrons and predicts a common linear increase of the width for all hadrons. Only when following the exact same analysis technique and experimental acceptance of the NA49 and NA61/SHINE collaborations, we find that the extracted value of the rapidity width of the $ϕ$ increases drastically for the highest beam energy. We conclude that the observed steep increase of the $ϕ$ rapidity width is a problem of limited detector acceptance and the simplified Gaussian fit approximation.
nucl-thnucl-exEPJA(2025)·0 citations
03
Production cross sections of superheavy elements: insights from the dinuclear system model with high-quality microscopic nuclear masses
Peng-Hui Chen · Chang Geng · Fei Niu · Zu-Xing Yang · Xiang-Hua Zeng · Zhao-Qing Feng
To accurately predict the synthesis cross-sections of superheavy elements, identifying the optimal projectile-target combinations and the evaporation channels at specific collision energies, we have attempted to utilize high-quality microscopic nuclear masses (HQMNM) within the dinuclear system (DNS) model, which are obtained by fitting experimental data with the Skyrme energy density functional theory (DFT), as published in Phys. Lett. B 851 (2024) 138578. The atomic nuclear mass serves as a crucial input for the DNS model, as the Q-values and separation energies it generates directly influence the calculated fusion and survival probabilities. Our calculations have reproduced the experimental data for hot fusion and have been compared with results based on the finite-range droplet model (FRDM12) mass calculations. Compared to the FRDM12 mass results, we have found that the HQMNM provides a better fit to the experimental outcomes. For the specific reaction of $^{48}\rm{Ca} + ^{243}\rm{Am} \rightarrow ^{291}\rm{Mc}^*$, we have conducted a detailed calculation of capture, fusion, and survival based on the HQMNM model and compared these with calculations based on other mass models. Based on these findings, we have systematically calculated available projectile target combinations for the synthesis of elements 119 and 120, and identified the optimal combinations. We provided the synthesis cross-sections, collision energies, and evaporation channels, offering a reference for conducting experiments on the synthesis of superheavy elements.
nucl-th0 citations
04
Microscopic investigation of wobbling motion in atomic nuclei using the triaxial projected shell model approach
J.A. Sheikh · S. Jehangir · G. H. Bhat
A systematic investigation of the wobbling band structures observed in odd-mass nuclei of $^{161, 163, 165, 167}$ Lu, $^{167}$ Ta $^{131}$ Cs, $^{135}$ Pr, $^{151}$ Eu, $^{183}$ Au, $^{133}$ Ba, $^{105}$ Pd, $^{133}$ La, $^{187}$ Au and $^{127}$ Xe is performed using the triaxial projected shell model (TPSM) approach. It is demonstrated that all the studied band structures have transverse wobbling mode, except for $^{133}$ La, $^{187}$ Au (negative parity), $^{183}$ Au (positive parity) and $^{127}$ Xe nuclei where the wobbling frequency increases with spin, indicating that the collective motion has a longitudinal character. To elucidate further the wobbling nature of the band structures, electromagnetic transition probabilities have been evaluated and it is observed that inter-band transitions are dominated by $E 2$ rather than $M 1$ as expected for a typical signature partner band. It is shown that TPSM approach provides a reasonable description of all the measured properties of the studied nuclei.
nucl-th0 citations
05
Longitudinal structure of the quark-gluon plasma from differently shaped nuclei
Jiangyong Jia🇺🇸 · Chunjian Zhang🇺🇸 · Shengli Huang🇺🇸
Ultrarelativistic collisions of atomic nuclei produce the quark--gluon plasma (QGP), an extremely hot, dense state of matter. The QGP behaves like a nearly perfect fluid, so its final-state momentum distributions can be inverted to reveal its initial-state geometry. This programme has succeeded in the transverse plane but made less progress along the beam, where short-range nonflow correlations mask the longitudinal signal. Anisotropic flow has been successfully used to image the shapes of the colliding nuclei; here we use nuclear shape to image the QGP's 3D geometry---the same idea in reverse. We show in simulations that the nonflow can be removed by comparing collisions of nuclei with similar masses but different shapes. We find that nuclear deformation changes the magnitude of the elliptic flow but not its longitudinal profile, so the shape difference recovers the full longitudinal structure. The predicted two-particle decorrelation map reveals both a highly non-linear rapidity dependence inaccessible to conventional observables, and an unquantified bias in standard flow measurements themselves. Our strategy extends to the longitudinal dependence of the QGP's triangularity and size. Nuclear shape thus becomes a tool for 3D imaging of the QGP and the quantum fluctuations of the nuclear wavefunctions that seed it.
nucl-thhep-phnucl-ex12 citations
06
An Area Law for Entanglement Entropy in Particle Scattering
Ian Low🇺🇸 · Zhewei Yin🇺🇸
The scattering cross section is the effective area of collision when two particles collide. Quantum mechanically, it is a measure of the probability for a specific process to take place. Employing wave packets to describe the scattering process, we compute the entanglement entropy in 2-to-2 scattering of particles in a general setting using the $S$ -matrix formalism. Applying the optical theorem, we show that the linear entropy $E_{2}$ is given by the elastic cross section $σ_{el}$ in unit of the transverse size $L^{2}$ of the wave packet, $E_{2} \sim σ_{el} / L^{2}$ , when the initial states are not entangled. The result allows for dual interpretations of the entanglement entropy as an area and as a probability. Since $σ_{el}$ is generally believed, and observed experimentally, to grow with the collision energy $s$ in the high energy regime, the result suggests a "second law" of entanglement entropy for high energy collisions. Furthermore, the Froissart bound places an upper limit on the entropy growth.
↳ hep-thcond-mat.stat-mechhep-phnucl-th+1PRD(2026)·28 citations
07
Superconducting multi-vortices and a novel BPS bound in chiral perturbation theory
Fabrizio Canfora🇨🇱 · Marcela Lagos🇨🇱 · Aldo Vera🇨🇱
We derive a novel BPS bound from chiral perturbation theory minimally coupled to electrodynamics at finite isospin chemical potential. At a critical value of the isospin chemical potential, a system of three first-order differential field equations (which implies the second-order field equations) for the gauge field and the hadronic profile can be derived from the requirement to saturate the bound. These BPS configurations represent magnetic multi-vortices with quantized flux supported by a superconducting current. The corresponding topological charge density is related to the magnetic flux density, but is screened by the hadronic profile. Such a screening effect allows to derive the maximal value of the magnetic field generated by these BPS magnetic vortices, being $B_{ma x} = 2, 04 \times 1 0^{14} G$ . The solution for a single BPS vortex is discussed in detail, and some physical consequences, together with the comparison with the magnetic vortices in the Ginzburg-Landau theory at critical coupling, are described.
↳ hep-thastro-ph.HEhep-phnucl-thJHEP(2024)·19 citations
08
The effective field theory of extended Wilson lines
Ryan Plestid🇺🇸
We construct the effective theory of electrically charged, spatially extended, infinitely heavy objects at leading power. The theory may be viewed as a generalization of NRQED for particles with a finite charge distribution where the charge radius and higher moments of the charge distribution are counted as $O (1)$ rather than $O (1/ M)$ . We show this is equivalent to a Wilson line traced by the worldline of an extended charge distribution. Our canonical use case is atomic nuclei with large charge $Z ≫ 1$ . The theory allows for the insertion of external operators and is sufficiently general to allow a treatment of both electromagnetic and weak mediated lepton-nucleus scattering including charged-current processes. This provides a first step towards the factorization of Coulomb regions, including structure dependence arising from a finite charge distribution, for scattering with nuclei.
↳ hep-phhep-thnucl-th2 citations
09
Deep TOV to characterize Neutron Stars
Praveer Tiwari🇮🇳 · Archana Pai🇮🇳
Astrophysical observations, theoretical models, and terrestrial experiments probe different regions of neutron star (NS) interior. Therefore, it is essential to consistently combine the information from these sources. This analysis requires multiple evaluations of Tolman Oppenheimer Volkoff equations which can become computationally expensive with a large number of observations. Further, multi-messenger astronomy requires rapid NS characterization via gravitational waves for efficient electromagnetic follow-up. In this work, we develop a novel neural network-based map from the EoS curve to the mass and radius of cold non-rotating NS. We estimate a speed-up of an order of magnitude when compared with the state-of-the-art RePrimAnd solver and an average error of 1e-3 when calculating the mass and radius of the neutron star. Additionally, we also develop neural network solvers for obtaining EoS curves from a physics conforming EoS model, FRZ $χ_{1.5}$ . We utilize this efficient continuous map to measure the sensitivity of model parameters of FRZ $χ_{1.5}$ towards mass and radius. We show that 8 out of 18 parameters of this model are sensitive by at least three orders of magnitude higher than the remaining 10 parameters. This information will be useful in further speeding up, as well as probing the crucial parameter space, in the parameter estimation from astrophysical observations using this physics-conforming EoS model.
↳ astro-ph.HEgr-qchep-phnucl-th8 citations
10
Towards Quarkonium Fragmentation from NRQCD in a Variable-Flavor Number Scheme
Francesco Giovanni Celiberto🇪🇸
We address quarkonium formation at moderate to large transverse momenta, where the single-parton collinear fragmentation prevails over the short-distance emission, directly from the hard sub-scattering, of the constituent heavy-quark pair. We rely on Non-Relativistic-QCD (NRQCD) Next-to-Leading Order (NLO) calculations for all parton fragmentation channels to quarkonia, taken as proxies for initial-scale inputs. Preliminary sets of Variable-Flavor Number-Scheme (VFNS) fragmentation functions (FFs) are built via a DGLAP scheme that properly accounts for evolution thresholds. Statistical errors are assessed via a Monte Carlo (MC), replica-like approach aimed at catching Missing Higher-Order Uncertainties (MHOUs).
↳ hep-phhep-exnucl-th20 citations
11
General amplitude of near-threshold hadron scattering for exotic hadrons
Katsuyoshi Sone🇯🇵 · Tetsuo Hyodo🇯🇵
We discuss the general behavior of the scattering amplitude with channel couplings near the two-body threshold. It is known that the Flatté amplitude, which is often used in the analysis of experimental data involving exotic hadrons, has some constraint in the near-threshold energy region. While the M-matrix gives the general expression of the scattering amplitude, it is not smoothly connected to the Flatté amplitude, due to the property of the determinant of the amplitude in channel space. In this paper, based on the effective field theory, we propose new parametrization of the scattering amplitude which gives the general expression near the threshold and has a well-defined limit reproducing the Flatté amplitude. We show that the nonresonant background contribution exists in the general amplitude even in the first order in the momentum. Finally, we quantitatively evaluate the cross sections by changing the strength of the background contribution. We find that the interference with the background term may induce a dip structure of the cross section near the threshold, in addition to the peak and threshold cusp structures.
↳ hep-phnucl-thPRC(2025)·11 citations
12
Dispersive approaches for the HVP and HLbL contributions to $(g - 2)_{μ}$
Martin Hoferichter🇨🇭
Calculations based on the analytic properties of the required matrix elements allow for a wide range of applications constraining the hadronic contributions to the anomalous magnetic moment of the muon $a_{μ} = (g - 2)_{μ} /2$ , both hadronic vacuum polarization (HVP) and hadronic light-by-light (HLbL) scattering. Here, we discuss such recent applications, including analyticity constraints on hadronic cross sections, radiative corrections, and isospin-breaking effects.
↳ hep-phhep-exhep-latnucl-th0 citations
13
The TDHF code Sky3D version 1.2
Abhishek · Paul Stevenson · Yue Shi · Esra Yüksel · Sait Umar
The Sky3D code has been widely used to describe nuclear ground states, collective vibrational excitations, and heavy-ion collisions. The approach is based on Skyrme forces or related energy density functionals. The static and dynamic equations are solved on a three-dimensional grid, and pairing is been implemented in the BCS approximation. This updated version of the code aims to facilitate the calculation of nuclear strength functions in the regime of linear response theory, while retaining all existing functionality and use cases. The strength functions are benchmarked against available RPA codes, and the user has the freedom of choice when selecting the nature of external excitation (from monopole to hexadecapole and more). Some utility programs are also provided that calculate the strength function from the time-dependent output of the dynamic calculations of the Sky3D code.
↳ physics.comp-phnucl-thComput.Phys.Commun.(2024)·16 citations
14
Heavy quark mass near the phase transition
Taesoo Song🇩🇪 · Qi Zhou🇨🇳
Assuming that the number densities of heavy flavor in hadron gas and in QGP are same at $T_{c}$ , we obtain the effective mass of heavy quark at $T_{c}$ from the comparison with the hadron resonance gas model which well describes particle yield in heavy-ion collisions. We find that charm quark mass at vanishing baryon chemical potential is around 1.8 GeV which is much heavier than QCD bare mass and close to $D$ meson mass. The mass slightly increases with increasing baryon chemical potential and then decreases. On the other hand, anticharm quark mass constantly decreases with increasing baryon chemical potential. Bottom quark mass has a similar pattern. Extending the hadron resonance gas model to a bit higher temperature beyond $T_{c}$ , the effective masses of charm and bottom quarks decrease with increasing temperature.
↳ hep-phnucl-thPhys.Scripta(2024)·6 citations
15
Color Chiral Cherenkov radiation and energy loss in quark-gluon plasma
Jeremy Hansen🇺🇸 · Kirill Tuchin🇺🇸
We introduce and investigate the Color Chiral Cherenkov effect which consists in radiation of the circularly polarized gluons by a fast color charge moving with constant velocity in the presence of the Chiral Magnetic current. We derive the transition rates for all gluon polarizations. We compute the contribution of the Color Chiral Cherenkov effect to the parton energy loss in the quark-gluon plasma.
↳ hep-phnucl-thPRD(2024)·5 citations
16
Adaptive Time Stepping for the Two-Time Integro-Differential Kadanoff-Baym Equations
Thomas Blommel · David J. Gardner · Carol S. Woodward · Emanuel Gull
The non-equilibrium Green's function gives access to one-body observables for quantum systems. Of particular interest are quantities such as density, currents, and absorption spectra which are important for interpreting experimental results in quantum transport and spectroscopy. We present an integration scheme for the Green's function's equations of motion, the Kadanoff-Baym equations (KBE), which is both adaptive in the time integrator step size and method order as well as the history integration order. We analyze the importance of solving the KBE self-consistently and show that adapting the order of history integral evaluation is important for obtaining accurate results. To examine the efficiency of our method, we compare runtimes to a state of the art fixed time step integrator for several test systems and show an order of magnitude speedup at similar levels of accuracy.
↳ physics.comp-phcond-mat.str-elnucl-thquant-phPRB(2024)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE