Nuclear Theory·nucl-th

Wednesday·June 19, 2024

9 papers—6 primary·3 cross-listed

01
Dynamics of the conserved net-baryon density near QCD critical point within inhomogeneous quark-gluon plasma profile
Shanjin Wu🇨🇳
This paper investigates the dynamics of the net-baryon multiplicity fluctuations near the QCD critical point, within the inhomogeneous temperature and baryon chemical potential profile of quark-gluon plasma from the hydrodynamics. The Langevin dynamics of conserved net-baryon density are solved numerically within the temperature and chemical potential profile borrowing from hydrodynamic simulation. It is found that the local systems at different rapidities reach the critical point at different proper times, owing to the inhomogeneous temperature and chemical potential. As a result, it is observed the pronounced enhancement of the magnitude for the net-baryon multiplicity fluctuations with large rapidity acceptance at the freeze-out surface, which is the consequence of the combined effect of critical slowing down and inhomogeneous profile.
nucl-thPRC(2025)·5 citations
02
Multichannel Dyson equation: derivation and analysis
Gabriele Riva · Pina Romaniello · J. Arjan Berger
In a recent letter [Phys. Rev. Lett. 131, 216401] we presented the multichannel Dyson equation (MCDE) in which two or more many-body Green's functions are coupled. In this work we will give further details of the MCDE approach. In particular we will discuss: 1) the derivation of the MCDE and the definition of the space in which it is to be solved; 2) the rationale of the approximation to the multichannel self-energy; 3) a diagrammatic analysis of the MCDE; 4) the recasting of the MCDE on an eigenvalue problem with an effective Hamiltonian that can be solved using standard numerical techniques. This work mainly focuses on the coupling between the one-body Green's function and the three-body Green's function to describe photoemission spectra, but the MCDE method can be generalized to the coupling of other many-body Green's functions and to other spectroscopies.
nucl-thcond-mat.mtrl-scicond-mat.str-elPRB(2024)·4 citations
03
Efficient production of $^{229 m}$ Th via nuclear excitation by electron capture
Jingyan Zhao · Adriana Pálffy · Christoph H. Keitel · Yuanbin Wu
The nuclear isomeric state $^{229 m}$ Th with an exceptionally low excitation energy makes the $^{229}$ Th isotope a crucial candidate for nuclear clocks and many other applications. Efficient and controllable production of $^{229 m}$ Th is essential and still remains a challenge. Here we report a novel approach for efficient production of $^{229 m}$ Th by the excitation of $^{229}$ Th to the above-lying excited state at $29.19$ keV energy via the process of nuclear excitation by electron capture (NEEC). We show theoretically that the production rate of $^{229 m}$ Th per nucleus with accessible conditions can be six orders of magnitude larger than the value experimentally demonstrated using $29$ -keV synchrotron radiation for this indirect excitation. With the efficient production of $^{229 m}$ Th, our results identify scenarios, as well as the characteristic NEEC signature with which NEEC events could be unambiguously identified, for a clear experimental identification of the long-sought NEEC phenomenon.
nucl-thPRC(2024)·10 citations
04
Two-center harmonic oscillator basis for Skyrme-DFT calculations (I): formalism and Proof of Principle
Adrián Sánchez-Fernández · Jacek Dobaczewski · Xuwei Sun · Herlik Wibowo
We present a new method to solve the nuclear density functional theory (DFT) equations using a two-center harmonic oscillator for Skyrme-like functionals, incorporating pairing and Coulomb interactions. The goal is to efficiently determine the fission and fusion configurations in nuclei. The Coulomb exchange term is evaluated exactly, allowing for a novel approach to neck formation without the Slater approximation, commonly used in space coordinate-based approaches. The new method has been implemented in the code {\sc hfodd}, enabling direct comparison with standard one-center solutions. This first paper focuses on deriving and implementing a methodology based on stable, precise, and exact applications of harmonic oscillator bases for the two fragments, which can either overlap or be separated by arbitrarily large distances. The implementation is tested on two proof-of-principle examples using light nuclei, specifically, $^{8}$ Be and $^{24}$ Mg.
nucl-thEPJA(2025)·1 citation
05
Constraining neutron star matter from the slope of the mass-radius curves
Márcio Ferreira🇵🇹 · Constança Providência🇵🇹
We analyse the implications of information about local derivatives from the mass-radius diagram in neutron star matter. It is expected that the next generation of gravitational wave and electromagnetic detectors will allow the determination of the neutron star radius and mass with a small uncertainty. Observations of neutron stars clustered around a given neutron star mass allow the estimation of local derivatives in the $M (R)$ diagram, which can be used to constrain neutron star properties. From a model-independent description of the neutron star equation of state, it is shown that a $M (R)$ curve with a negative slope at 1.4 $M_{⊙}$ predicts a $2 M_{⊙}$ neutron star radius below 12 km. Furthermore, a maximum mass below 2.3 $M_{⊙}$ is obtained if the $M (R)$ slope is negative in the whole range of masses above $1 M_{⊙}$ , and a maximum mass above 2.4 $M_{⊙}$ requires the $M (R)$ slope to be positive in some range of masses. Constraints on the mass-radius curve of neutron stars will place strong constraints on microscopic models.
nucl-thastro-ph.HEhep-phPRD(2024)·22 citations
06
Inverse-scattering separable NN potential constrained to phase-shift data up to 2.5 GeV. I.- Uncoupled states
H. F. Arellano🇨🇱 · N. A. Adriazola🇨🇱
We introduce a new method to construct, within inverse-scattering theory, an energy-independent separable potential capable of reproducing exactly both phase shift and absorption over a predefined energy range. The approach relies on the construction of non-overlapping multi-rank separable potentials, whose form factors are obtained by solving linear equations on intervals where the $K$ matrix does have zeros. Applications are made to nucleon-nucleon $N N$ interactions constrained to the SAID-SP07 phase-shift analysis up to 2.5 GeV lab energy. The inversion potentials are channel dependent with rank dictated by the number of zeros of the $K$ matrix, reproducing the data up to a selected upper momentum. The account for absorption yields complex separable form factors, resulting in a non-Hermitian potential. Applications are restricted to $N N$ spin-uncoupled states considering a Schrödinger-like wave equation with minimal relativity. Its extension to spin-coupled states and relativistic kernels are discussed.
nucl-thEPJA(2024)·2 citations
07
Study on relativistic transformations for thermodynamic quantities: Boltzmann-Gibbs and Tsallis blast-wave models
A.S. Parvan🇷🇺
This study derives the relativistic transformations of thermodynamic quantities from the Lorentz transformations applied to the four-momentum components of a thermodynamic system, which is stationary in the inertial reference frame $K_{0}$ and moves at constant velocity relative to the laboratory frame $K$ . Thermodynamic variables are introduced into the formalism via the zeroth component of the four-momentum in $K_{0}$ , representing the system's internal energy. By treating the three-momentum as an independent state variable, thermodynamic quantities are defined by differentiating the zeroth component of the four-momentum (the Hamiltonian) in the reference frame $K$ with respect to the independent state variables, yielding the fundamental thermodynamic potential. This approach results in the Non-Planck transformations, which differ from the Planck transformations by a factor of $α$ . In contrast, by adopting the three-velocity as an independent state variable, thermodynamic quantities are obtained by differentiating the negative Lagrangian, derived from the zeroth component of the four-momentum via Legendre transformations, with respect to the independent state variables, producing the conjugate fundamental thermodynamic potential. This yields the Planck transformations. Conversely, the Ott transformations are derived from the zeroth component of the four-momentum by treating velocity as an independent state variable. This approach conflicts with the principles of mechanics, resulting in an energy that does not qualify as a thermodynamic potential. To validate these findings, we analyze an ultrarelativistic ideal gas of quarks and gluons within the Stefan-Boltzmann limit. Furthermore, we develop consistent Boltzmann-Gibbs and Tsallis blast-wave models for finite-volume freeze-out firecylinders in heavy ion collisions, incorporating Planck and Ott transformations.
↳ hep-phnucl-thEPJA(2025)·0 citations
08
Spin-independent interactions of Dirac Fermionic Dark Matter in the composite Higgs models
M. G. Belyakova🇷🇺 · R. Nevzorov🇷🇺
According to recent measurements, dark matter magnetic dipole moment is strongly constrained. In the composite Higgs models the magnetic dipole moment of the Dirac dark matter fermion and its mass can be suppressed by the approximate U(1) symmetry. We consider E_6 inspired composite Higgs model (E_6CHM) with U(1) symmetry violating operators, which give rise to dark matter's mass and coupling constant to Higgs boson. The dependence of the spin-independent dark matter-nucleon scattering cross section on the E_6CHM parameters is explored. We argue that there are regions of the parameter space which are still safe from all current constraints and may lead to spectacular LHC signatures.
↳ hep-phastro-ph.COhep-exhep-th+1PRD(2024)·4 citations
09
Neural Ordinary Differential Equations for Mapping the Magnetic QCD Phase Diagram via Holography
Rong-Gen Cai🇨🇳 · Song He🇨🇳 · Li Li🇨🇳 · Hong-An Zeng🇨🇳
The QCD phase diagram is crucial for understanding strongly interacting matter under extreme conditions, with major implications for cosmology, neutron stars, and heavy-ion collisions. We present a novel holographic QCD model utilizing neural ordinary differential equations (ODEs) to map the QCD phase diagram under magnetic field $B$ , baryon chemical potential $μ_{B}$ , and temperature $T$ . By solving the inverse problem of constructing a gravitational theory from Lattice QCD data, we reveal an unprecedentedly rich phase structure at finite $B$ , including multiple critical endpoints (CEPs) in strong magnetic fields. Specifically, for { $B = 1.618 GeV^{2} = 2.592 \times 1 0^{19}$ Gauss}, we identify two distinct CEPs at $(T_{C} = 87.3 MeV, μ_{C} = 115.9 MeV)$ and $(T_{C} = 78.9 MeV, μ_{C} = 244.0 MeV)$ . Notably, the critical exponents vary depending on the CEP's location, and the conventional scaling relations can be violated in the presence of strong magnetic fields. These findings significantly advance our understanding of the QCD phase structure and provide concrete predictions for experimental validation at upcoming facilities such as FAIR, JPARC-HI, and NICA.
↳ hep-thgr-qchep-phnucl-thSCPMA(2026)·43 citations

Affiliations

first authorsco-authorsvia INSPIRE