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Nuclear Theory·nucl-th

Tuesday·July 29, 2025

13 papers—7 primary·6 cross-listed

All13Primary7Cross-lists6
  1. 01

    Nuclear Schiff moment of fluorine isotope F

    Kia Boon Ng🇨🇦 · Stephan Foster🇨🇦 · Lan Cheng🇺🇸 · Petr Navratil🇨🇦 · Stephan Malbrunot-Ettenauer🇨🇦

    Nuclear Schiff moments (NSMs) are sensitive probes for physics beyond the Standard Model of particle physics, signaling violations of time-reversal and parity-inversion symmetries in atomic nuclei. In this Letter, we report the first-ever calculation of a NSM in a nuclear ab initio framework, employing the no-core shell model to study the fluorine isotope F. We further perform quantum-chemistry calculations to evaluate the sensitivity of the hafnium monofluoride cation, HfF, to the NSM of F. Combined with recent high-precision measurements of the molecular electric dipole moment of HfF, our results enable the first experimental bound on the NSM of F. Although the resulting bounds on the pion-nucleon-nucleon (NN) coupling constants are not yet the most stringent, this work establishes the foundation for constraining NN interactions using nuclear ab initio methods.

    nucl-thphysics.atom-phphysics.comp-phPRL(2026)·8 citations
  2. 02

    Existence of a fourth Airy elephant in the nuclear rainbows for C+C scattering

    S. Ohkubo · Y. Hirabayashi

    The number of gross structures in the 90 excitation function for C+C elastic scattering, often called Airy elephants, has been of great interest. These structures are caused by refractive scattering and are separated by Airy minima. Their importance stems from their close relationship to the interaction potential between two C nuclei, which also describes the molecular resonances of the compound system at lower energies. Although a unique deep potential was usually determined from rainbow scattering at higher energies, a puzzling discrepancy persisted: the energy at which the Airy minimum crosses 90 was 67 MeV for C+C. This is remarkably low compared to approximately 100 MeV for both the O+C and O+O systems. This question remained unanswered until the discovery of the secondary rainbow in the C+C system. We report for the first time that the highest energy at which the dynamically generated Airy minimum of the secondary rainbow crosses 90 is about 100 MeV. This demonstrates that the fourth Airy elephant exists between the Airy minimum of the primary nuclear rainbow and that, , of the secondary rainbow. The long-standing problem concerning the Airy minima and Airy elephants has finally been resolved after decades of concern by recognizing the existence of a dynamically generated secondary rainbow in C+C scattering.

    nucl-thEPJA(2025)·1 citation
  3. 03

    Nonlinear causality of Israel-Stewart theory with diffusion

    Ian Cordeiro🇺🇸 · Fábio S. Bemfica🇺🇸 · Enrico Speranza🇮🇹 · Jorge Noronha🇺🇸

    We present the first fully nonlinear causality constraints in dimensions for Israel-Stewart theory in the presence of energy and number diffusion in the Eckart and Landau hydrodynamic frames, respectively. These constraints are algebraic inequalities that make no assumption on the underlying geometry of the spacetime or the equation of state. In order to highlight the distinct physical and structural behavior of the two hydrodynamic frames, we discuss the special ultrarelativistic ideal gas equation of state considered in earlier literature in dimensions, and show that our general constraints reduce to their results upon an appropriate choice of angles. For this equation of state in both and dimensions one can show that: (i) there exists a region allowed by nonlinear causality in which the baryon current transitions into a spacelike vector in the Landau frame, and (ii) an analogous argument shows that the solutions of the Eckart frame equations of motion never violate the dominant energy condition, assuming nonlinear causality holds. We then compare our results with those from linearized Israel-Stewart theory and show that the linear causality bounds fail to capture the new physical constraints on energy and number diffusion that are successfully obtained through our nonlinear causality approach.

    nucl-thastro-ph.HEgr-qchep-phPRD(2026)·9 citations
  4. 04

    Vibrational Modes in Strongly Deformed Nuclei

    Y. Tsunoda🇯🇵 · T. Otsuka🇯🇵 · N. Shimizu🇯🇵 · T. Duguet🇫🇷 · Y. Utsuno🇯🇵 · T. Abe🇯🇵

    Low-energy vibrational excitations associated with the fluctuation of quadrupole deformed shapes are discussed within the frame of state-of-the-art Configuration Interaction calculations, actually performed via the Quasi-particle Vacua Shell Model version of the Monte Carlo Shell Model. Recently, low-lying bands in heavy strongly deformed nuclei were shown to be rotational = 2 excitations of triaxially deformed states (see T. Otsuka \etal, Eur. Phys. J. A 61, 126 (2025)) rather than vibrational excitations as traditionally interpreted. In this context, it is important to identify possible low-lying vibrational excitations and to characterize the excitation energy at which they emerge. Focusing on two typical examples, Er and Dy, vibrational states are indeed identified above the band using an extended version of the so-called T-plot. The phenomenon of shape coexistence is also shown to produce low-lying states below such vibrational band heads. These results suggest novel and rich structures in heavy deformed nuclei. While experimental counterparts are seen for some of such states, others are predictions opening doors to future dedicated experiments.

    nucl-thnucl-ex3 citations
  5. 05

    Understanding the correlation between elliptic and triangular flow

    Mubarak Alqahtani🇸🇦 · Jean-Yves Ollitrault🇫🇷

    The relative correlation between the magnitudes of elliptic flow () and triangular flow () has been accurately measured in nucleus-nucleus collisions at the LHC collider. As a function of the centrality of the collision, it changes sign and varies non-monotonically. We show that this is naturally explained by two combined effects. The first effect is a skewness in initial-state fluctuations, which is quantified by the correlation between the geometry-driven elliptic deformation in the reaction plane and the fluctuation-driven triangularity . We introduce an intensive measure of this skewness, which is generically of order unity and depends weakly on the system size and centrality. We evaluate its magnitude using Monte Carlo simulations of the initial state, which show that it is sensitive to the nucleon width. The second effect is the fluctuation of impact parameter relative to centrality classifiers used by experiment. The ATLAS collaboration uses two different centrality classifiers, the multiplicity and the transverse energy . We fit both sets of results for Pb+Pb collisions up to centrality with a single parameter, the intensive mixed skewness. Its value inferred from experiment agrees with theoretical expectations.

    nucl-thhep-exhep-phnucl-exPLB(2026)·2 citations
  6. 06

    Single-flavor heavy baryons in a strong magnetic field

    Gaoqing Cao🇨🇳 · Shuang Wu🇨🇳

    In this work, we study the properties of single-flavor heavy baryons, and , in a strong magnetic field. For that sake, we simply treat the baryons as quark-diquark two-body systems, and a systematic formalism is developed to deal with two-body Schrdinger equations in a magnetic field. It is found that: 1. The orbital properties of are almost not affected by the magnetic field. 2. is more tightly bound in the presence of a magnetic field. 3. The magnetic-spin effect dominates over the magnetic-orbital effect. Applying to peripheral heavy ion collisions, is much better than to explore the magnetic effect, and the discovery of could be more promising.

    nucl-thhep-phPRD(2025)·2 citations
  7. 07

    Impact of ground-state correlations on the multipole response of nuclei: Ab initio calculations of moment operators

    Andrea Porro · Achim Schwenk · Alexander Tichai

    We develop a framework that allows to calculate integrated properties of the nuclear response from first principles. Using the ab initio in-medium similarity renormalization group (IMSRG), we calculate the expectation values of moment operators that are linked to the multipole response of nuclei. This approach is applied to the isoscalar mono- and quadrupole as well as the isovector dipole response of closed-shell nuclei from He to Ni for different chiral two- and three-nucleon interactions. We find that the inclusion of many-body correlations in the nuclear ground state significantly impacts the multipole response when going from the random-phase approximation to the IMSRG level. Our IMSRG calculations lead to an improved description of experimental data in O and Ca, including a good reproduction of the Thomas-Reiche-Kuhn enhancement factor. These findings highlight the utility of the moment method as a benchmark for other ab initio approaches that describe nuclear response functions through the explicit treatment of excited states.

    nucl-thPRC(2025)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE