Nuclear Theory·nucl-th

Tuesday·November 12, 2024

15 papers—8 primary·7 cross-listed

09
Second-order hyperfine correction to H, D, and $^{3}$ He energy levels
Krzysztof Pachucki · Vojtěch Patkóš · Vladimir A. Yerokhin
The complete second-order hyperfine-interaction correction is calculated for centroid energy levels of H, D, and $^{3}$ He atoms. For $^{3}$ He, the corrections of $- 2.075$ ~kHz and $- 0.305$ ~kHz beyond the leading hyperfine-mixing contribution are obtained for the $2^{1} S$ and $2^{3} S$ states, respectively. These results shift the nuclear charge radii difference derived from the $^{3}$ He - $^{4}$ He isotope shift and largely resolve the previously reported disagreement between the muonic and electronic helium determinations [van der Werf et al., arXiv:2306.02333 (2023); Schuhmann et al., arXiv:2305.11679 (2023)].
↳ physics.atom-phnucl-thPRA(2024)·11 citations
10
Boost-invariant spin hydrodynamics with spin feedback effects
Zbigniew Drogosz🇵🇱 · Wojciech Florkowski🇵🇱 · Natalia Łygan🇵🇱 · Radoslaw Ryblewski🇵🇱
A recently formulated extension of perfect spin hydrodynamics, which includes second-order corrections in the spin polarization tensor to the energy-momentum tensor and baryon current, is studied in the case of a one-dimensional boost-invariant expansion. The presence of second-order corrections introduces feedback from spin dynamics on the hydrodynamic background, constraining possible spin polarization configurations. However, as long as the magnitude of the spin polarization tensor remains small (below unity in natural units), the permitted spin dynamics differs very little from that found in the case without the second-order corrections.
↳ hep-phnucl-thPRC(2025)·15 citations
11
The effect of pressure anisotropy on quark stars structure in the Starobinsky model
Takol Tangphati🇹🇭 · İzzet Sakallı🇨🇱 · Ayan Banerjee🇿🇦 · Anirudh Pradhan🇮🇳
The structure and stability of quark stars (QSs) made of interacting quark matter are discussed in this study, taking color superconductivity and perturbative QCD corrections into account. By combining this EoS with the Tolman-Oppenheimer-Volkoff (TOV) equations, we explore the mass-radius ( $M - R$ ) relations of QSs. The analysis is conducted within the framework of $R^{2}$ gravity, where the gravity model is described by $f (R) = R + a R^{2}$ . Our primary goal is to investigate how variations in the $R^{2}$ gravity parameter $a$ affect the mass-radius and mass-central density ( $M - ρ_{c}$ ) relationships of QSs. Furthermore, we study the dynamical stability of these stars by analyzing the impact of anisotropy parameters $β$ and the interaction parameter $λ$ derived from the EoS, on their stability. Our results demonstrate that the presence of pressure anisotropy plays a significant role in increasing the maximum mass of QSs, with potential implications for the existence of super-massive pulsars. These findings are in agreement with recent astronomical observations, which suggest the possibility of neutron stars exceeding $2 M_{⊙}$ .
↳ hep-thastro-ph.HEgr-qcnucl-thCPC(2025)·8 citations
12
Dynamical constraints on pseudo-gauge transformations
Zbigniew Drogosz🇵🇱 · Wojciech Florkowski🇵🇱 · Mykhailo Hontarenko🇵🇱 · Radoslaw Ryblewski🇵🇱
Classical pseudo-gauge transformations are discussed in the context of hydrodynamic models of heavy-ion collisions. A decomposition of the pseudo-gauge transformation into Lorentz-invariant tensors is made, which allows for better interpretation of its physical consequences. For pseudo-gauge transformations connecting two symmetric energy-momentum tensors, we find that the super-potential $Φ^{λ μν}$ must obey a conservation law of the form $\partial_{λ} Φ^{λ μν} = 0$ . This equation, referred to below as the STS condition, represents a constraint that is hardly possible to be satisfied for tensors constructed out of the basic hydrodynamic variables such as temperature, baryon chemical potential, and the hydrodynamic flow. However, in a special case of the boost-invariant flow, the STS condition is automatically fulfilled and a non-trivial residual pseudo-gauge transformation defined by a single scalar field is allowed. In this case the bulk and shear viscosity coefficients become pseudo-gauge dependent; however, their specific linear combination appearing in the equations of motion remains pseudo-gauge invariant. This finding provides new insights into the role of pseudo-gauge transformations and pseudo-gauge invariance.
↳ hep-phnucl-thPLB(2025)·12 citations
13
Mass measurements of neutron-rich nuclides using the Canadian Penning Trap to inform predictions in the $r$ -process rare-earth peak region
D. Ray · N. Vassh · B. Liu · A.A. Valverde · M. Brodeur · J.A. Clark · G.C. McLaughlin · M.R. Mumpower · R. Orford · W.S. Porter · G. Savard · K. S. Sharma and 16 other authors
Studies aiming to determine the astrophysical origins of nuclei produced by the rapid neutron capture process ( $r$ process) rely on nuclear properties as inputs for simulations. The solar abundances can be used as a benchmark for such calculations, with the $r$ -process rare-earth peak (REP) around mass number ( $A$ ) 164 being of special interest due to its presently unknown origin. With the advancement of rare isotope beam production over the last decade and improvement in experimental sensitivities, many of these REP nuclides have become accessible for measurement. Masses are one of the most critical inputs as they impact multiple nuclear properties, namely the neutron-separation energies, neutron capture rates, $β$ -decay rates, and $β$ -delayed neutron emission probabilities. In this work, we report masses of 20 neutron-rich nuclides (along the Ba, La, Ce, Pr, Nd, Pm, Gd, Dy and Ho isotopic chains) produced at the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory. The masses were measured with the Canadian Penning trap (CPT) mass spectrometer using the Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) technique. We then use these new masses along with previously published CPT masses to inform predictions for a Markov Chain Monte Carlo (MCMC) procedure aiming to identify the astrophysical conditions consistent with both solar data and mass measurements. We show that the MCMC responds to this updated mass information, producing refined results for both mass predictions and REP abundances.
↳ nucl-exnucl-th5 citations
14
Heavy Flavor Production at the Large Hadron Collider: A Machine Learning Approach
Raghunath Sahoo🇮🇳
Charmonia suppression has been considered as a smoking gun signature of quark-gluon plasma. However, the Large Hadron Collider has observed a lower degree of suppression as compared to the Relativistic Heavy Ion Collider energies, due to regeneration effects in heavy-ion collisions. Though proton collisions are considered to be the baseline measurements to characterize a hot and dense medium formation in heavy-ion collisions, LHC proton collisions with its new physics of heavy-ion-like QGP signatures have created new challenges. To understand this, the inclusive charmonia production at the forward rapidities in the dimuon channel is compared with the corresponding measurements in the dielectron channel at the midrapidity as a function of final state charged particle multiplicity. None of the theoretical models quantitatively reproduce the experimental findings leaving out a lot of room for theory. To circumvent this and find a reasonable understanding, we use machine learning tools to separate prompt and nonprompt charmonia and open charm mesons using the decay daughter track properties and the decay topologies of the mother particles. Using PYTHIA8 data, we train the machine learning models and successfully separate prompt and nonprompt charm hadrons from the inclusive sample to study various directions of their production dynamics. This study enables a domain of using machine learning techniques, which can be used in the experimental analysis to better understand charm hadron production and build possible theoretical understanding.
↳ hep-phhep-exnucl-exnucl-th0 citations
15
A Quantum Annealing Protocol to Solve the Nuclear Shell Model
Emanuele Costa🇪🇸 · Axel Perez-Obiol🇪🇸 · Javier Menendez🇪🇸 · Arnau Rios🇪🇸 · Artur Garcia-Saez🇪🇸 · Bruno Julia-Diaz🇪🇸
The nuclear shell model accurately describes the structure and dynamics of atomic nuclei. However, the exponential scaling of the basis size with the number of degrees of freedom hampers a direct numerical solution for heavy nuclei. In this work, we present a quantum annealing protocol to obtain nuclear ground states. We propose a tailored driver Hamiltonian that preserves a large gap and validate our approach in a dozen nuclei with basis sizes up to $1 0^{5}$ using classical simulations of the annealing evolution. We explore the relation between the spectral gap and the total time of the annealing protocol, assessing its accuracy by comparing the fidelity and energy relative error to classical benchmarks. While the nuclear Hamiltonian is non-local and thus challenging to implement in current setups, the estimated computational cost of our annealing protocol on quantum circuits is polynomial in the single particle basis size, paving the way to study heavier nuclei.
↳ quant-phnucl-thSciPost Phys.(2025)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE

Second-order hyperfine correction to H, D, and 3He energy levels

Boost-invariant spin hydrodynamics with spin feedback effects

The effect of pressure anisotropy on quark stars structure in the Starobinsky model

Dynamical constraints on pseudo-gauge transformations

Mass measurements of neutron-rich nuclides using the Canadian Penning Trap to inform predictions in the r-process rare-earth peak region

Heavy Flavor Production at the Large Hadron Collider: A Machine Learning Approach

A Quantum Annealing Protocol to Solve the Nuclear Shell Model

Affiliations

Second-order hyperfine correction to H, D, and $^{3}$ He energy levels

Mass measurements of neutron-rich nuclides using the Canadian Penning Trap to inform predictions in the $r$ -process rare-earth peak region