PaperPanorama

Nuclear Theory·nucl-th

Monday·December 30, 2024

19 papers—10 primary·9 cross-listed

All19Primary10Cross-lists9
  1. 01

    Strongly interacting matter in extreme magnetic fields

    Prabal Adhikari🇺🇸 · Martin Ammon🇩🇪 · Sidney S. Avancini🇧🇷 · Alejandro Ayala🇲🇽 · Aritra Bandyopadhyay🇩🇪 · David Blaschke🇵🇱 · Fabio L. Braghin🇧🇷 · Pavel Buividovich🇬🇧 · Rafael P. Cardoso🇧🇷 · Casey Cartwright🇳🇱 · Jorge David Castaño-Yepes🇨🇱 · Maxim Chernodub🇫🇷 and 49 other authors

    Magnetic fields are ubiquitous across different physical systems of current interest; from the early Universe, compact astrophysical objects and heavy-ion collisions to condensed matter systems. A proper treatment of the effects produced by magnetic fields during the dynamical evolution of these systems, can help to understand observables that otherwise show a puzzling behavior. Furthermore, when these fields are comparable to or stronger than \Lambda_QCD, they serve as excellent probes to help elucidate the physics of strongly interacting matter under extreme conditions of temperature and density. In this work we provide a comprehensive review of recent developments on the description of QED and QCD systems where magnetic field driven effects are important. These include the modification of meson static properties such as masses and form factors, the chiral magnetic effect, the description of anomalous transport coefficients, superconductivity in extreme magnetic fields, the properties of neutron stars, the evolution of heavy-ion collisions, as well as effects on the QCD phase diagram. We describe recent theory and phenomenological developments using effective models as well as LQCD methods. The work represents a state-of-the-art review of the field, motivated by presentations and discussions during the "Workshop on Strongly Interacting Matter in Strong Electromagnetic Fields" that took place in the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) in the city of Trento, Italy, September 25-29, 2023.

    nucl-thPPNP(2026)·69 citations
  2. 02

    Effects of chiral symmetry restoration on dilepton production in heavy ion collisions

    Wen-Hao Zhou🇨🇳 · Che Ming Ko🇺🇸 · Kai-Jia Sun🇨🇳

    Because of their weak interactions with the strongly interacting matter produced in relativistic heavy-ion collisions, dileptons provide an ideal probe of the early dynamics of these collisions. Here, we study dilepton production using a partonic transport model that is based on an extended Nambu-Jona-Lasinio (NJL) model. In this model, the in-medium quark masses decrease with increasing temperature as a result of the restoration of chiral symmetry. We find that the extracted temperature from dileptons of intermediate masses agrees well with the temperature of the partonic matter, suggesting that dilepton production can be used as a thermometer for the produced partonic matter. Our results also indicate that the extracted in-medium quark masses decrease with increasing dilepton temperature, implying that dilepton production can further serve as a probe of chiral symmetry restoration in high energy heavy-ion collisions.

    nucl-thhep-th4 citations
  3. 03

    Nuclear matter properties from chiral-scale effective theory including a dilatonic scalar meson

    Lu-Qi Zhang🇨🇳 · Yao Ma🇨🇳 · Yong-Liang Ma🇨🇳

    Chiral effective theory has become a powerful tool for studying the low-energy properties of QCD. In this work, we apply an extended chiral effective theory -- chiral-scale effective theory -- including a dilatonic scalar meson to study nuclear matter and find that the properties around saturation density can be well reproduced. Compared to the traditionally used Walecka-type models in nuclear matter studies, our approach improves the behavior of symmetry energy and the incompressibility coefficient in describing empirical data without introducing additional freedoms. Moreover, the predicted neutron star structures fall within the constraints of GW170817, PSR J0740+6620, and PSR J0030+0451, while the maximum neutron star mass can reach about with a pure hadronic phase. Additionally, we find that symmetry patterns of the effective theory significantly impact neutron star structures. %In chiral-scale effective theory, effective operators are well organized by chiral-scale orders and freedoms induced by QCD symmetry patterns. We believe that introducing this type of theory into nuclear matter studies can lead to a deeper understanding of QCD, nuclear matter, and compact astrophysical objects.

    nucl-thastro-ph.HEhep-phCPC(2026)·6 citations
  4. 04

    Deformation and core decoupling in the spectrum of C

    Tadahiro Suhara · Yasutaka Taniguchi · Wataru Horiuchi · Shin Watanabe · Takenori Furumoto

    The coexistence of various structures, such as diverse shapes and cluster structures, is a fundamental property of atomic nuclei. In neutron-rich nuclei, a core structure can compete with nuclear deformation due to the small neutron separation energy. A neutron-rich carbon isotope, C, exemplifies the appearance of the deformation and the core+ decoupling in its spectrum, which is desirable for a deeper understanding of the coexistence phenomena in neutron-rich nuclei. We aim to describe and understand this coexistence phenomenon in the low-lying levels of C in a unified manner considering explicitly the degrees of freedom of both the quadrupole deformation and the relative motion between a C core and a valence neutron. We adopt the generator coordinate method (GCM) with the antisymmetrized molecular dynamics (AMD) to describe various configurations. We superpose various basis wave functions generated by the energy variation by imposing two types of constraints: one incorporating the degree of the quadrupole deformation and the other taking care of the relative motion between a C core and a valence neutron. We find that the experimental energy level is well reproduced by the present method, including both deformed and C+ configurations. The ground and second excited states exhibit a triaxially deformed shape, while the main component of the first excited state is a C() core plus an -wave neutron configuration. The tail of the valence neutron is significantly improved by including the C+ basis functions explicitly. The explicit inclusion of both the quadrupole deformation and the relative motion between a core and a valence neutron is essential to describe the coexistence phenomena observed in neutron-rich nuclei in the AMD+GCM framework.

    nucl-thPRC(2025)·1 citation
  5. 05

    Investigating nuclear density profiles to reveal particle-hole configurations in the island of inversion

    R. Barman (1, 2) · W. Horiuchi (3, 4, 2) · M. Kimura (2) · R. Chatterjee (1) ((1) Indian Institute of Technology Roorkee, Roorkee, India (2) RIKEN Nishina Center, Wako, Japan, (3) Osaka Metropolitan University, Osaka, Japan, (4) Hokkaido University, Sapporo, Japan)

    Background: In the mass regions with an abnormal shell structure, the so-called ``island of inversion," the spin-parity of odd-mass nuclei provides quantitative insights into the shell evolution. However, the experimental determination of the spin-parity is often challenging, leaving it undetermined in many nuclei. Purpose: We discuss how the shell structure affects the density profiles of nuclei in the island of inversion and investigate whether these can be probed from the total reaction and elastic scattering cross sections. Method: The antisymmetrized molecular dynamics (AMD) is employed to generate various particle-hole configurations and predict the energy levels of these nuclei. The obtained density distributions are used as inputs to the Glauber model, which is employed to calculate the total reaction and elastic scattering cross sections for revealing their relationship to the particle-hole configurations. Results: In addition to the well-known correlation between nuclear deformation and radius, we show the correlations between the particle-hole configurations and both central density and diffuseness. We show that different particle-hole configurations are well reflected in the total reaction and elastic scattering cross sections. Conclusion: The total reaction and elastic scattering cross sections are useful probes to identify the spin-parity of nuclei when different particle-hole configurations coexist.

    nucl-thPRC(2025)·3 citations
  6. 06

    Probing medium response via strangeness enhancement around quenched jets

    Ao Luo🇨🇳 · Shanshan Cao🇨🇳 · Guang-You Qin🇨🇳

    Jet-induced medium excitation is a crucial part of jet interactions with the quark-gluon plasma (QGP) in relativistic heavy-ion collisions, and has recently been confirmed by experiment for the first time. Based on the AMPT model simulation, we propose the strangeness enhancement around quenched jets as a novel signature of jet-induced medium excitation. By applying the jet-particle correlation techniques, we calculate jet-induced particle yields around the jets and find a significant enhancement of the strange-to-non-strange-hadron ratio and the double-to-single-strange-hadron ratio correlated with jets in relativistic nucleus-nucleus collisions relative to proton-proton collisions. This enhancement increases with both the strength of jet-QGP interactions and the radial distance from jet axis. These observations align with the features of jet-induced medium excitation and parton coalescence in hadron formation, and await experimental validation in the future measurements.

    nucl-thhep-phnucl-exPLB(2025)·3 citations
  8. 08

    Impact of dineutrons on nuclear compositions of a core-collapse supernova

    Tatsuya Matsuki🇯🇵 · Shun Furusawa🇯🇵 · Katsuhiko Suzuki🇯🇵

    We study the nuclear compositions in the central region of a core-collapse supernova, assuming the existence of dineutrons () and tetraneutrons (). At 100~ms after core bounce, and are more abundant than deuterons within radii of approximately 100 and 50~km, respectively. Compared to the model ignoring the existence of and , the mass fraction of neutrons up to a radius of 100~km reduces, while the mass fractions of protons, deuterons, and increase. Due to the uncertainties in the properties of and , we investigate the influence of their binding energies on the nuclear composition. We find the binding energy of has only a modest effect on the overall composition, except for its own mass fraction, while that of has a negligible impact.

    nucl-thastro-ph.HEastro-ph.SRhep-phPRC(2025)·3 citations
  9. 09

    The consistent analyses for determination of the point-nucleon distributions by electron and proton scatterings

    Toshio Suzuki · Rika Danjo · Toshimi Suda · Masayuki Matsuzaki · Tomotsugu Wakasa

    Electron scattering cross section, as well as proton scattering cross section, observes the point-proton and the point-neutron distributions, but both cross sections are not able to determine them separately. If they are analyzed consistently with each other, there is a possibility to determine them with less ambiguity.The consistency can be examined through the moments of the charge distribution, which linearly depend on the moments of the point-proton and -neutron distributions.

    nucl-thFront.in Phys.(2025)·0 citations
  10. 10

    Application of normalizing flows to nuclear many-body perturbation theory

    Pengsheng Wen · Jeremy W. Holt · Albany Blackburn

    Many-body perturbation theory provides a powerful framework to study the ground state and thermodynamic properties of nuclear matter as well as associated single-particle potentials and response functions within a systematic order-by-order expansion. However, computational challenges can emerge beyond the lowest orders of perturbation theory, especially when computing both single-particle potentials and response functions, which in general are complex-valued and require Cauchy principal value calculations of high-dimensional integrals. We demonstrate that normalizing flows are suitable for Monte Carlo importance sampling of both regular and irregular functions appearing in nuclear many-body calculations. Normalizing flows are a class of machine learning models that can be used to build and sample from complicated distributions through a bijective mapping from a simple base distribution. Furthermore, a well-trained model for a certain target integrand can be efficiently transferred to calculate related integrals with varying physical conditions. These features can enable more efficient tabulations of nuclear physics inputs to numerical simulations of supernovae and neutron star mergers across varying physical conditions and nuclear force models.

    nucl-thPRC(2026)·6 citations
  11. 11

    Analysis of NOvA and MicroBooNE charged-current inclusive neutrino measurements within the SuSAv2 framework

    J. Gonzalez-Rosa🇪🇸 · G. D. Megias🇪🇸 · J. A. Caballero🇪🇸 · M. B. Barbaro🇮🇹

    In this work we compare the SuSAv2 model, based on the superscaling phenomenon and the relativistic mean field theory, with charged-current inclusive neutrino cross sections from the NOvA and MicroBooNE experiments, whose targets are composed primarily by 12 C and 40 Ar, respectively. The neutrino energy in these experiments covers a kinematic range from tens of MeV to roughly 20 GeV. Thus, we consider the different reaction mechanisms that contribute significantly to these kinematics, namely quasielastic, two-particle two-hole meson exchange currents, resonances and deep inelastic scattering contributions.

    ↳ hep-phnucl-thPRD(2025)·6 citations
  12. 12

    Excitation of the isoscalar giant monopole resonance using 6Li inelastic scattering

    J. Arroyo · U. Garg · H. Akimune · G. P. A. Berg · D. C. Cuong · M. Fujiwara · M. N. Harakeh · M. Itoh · T. Kawabata · K. Kawase · J.T. Matta · D. Patel · M. Uchida · M. Yosoi

    The incompressibility of infinite nuclear matter (K_\infty) is a parameter in the description of the nuclear equation of state that governs the energy cost associated with density oscillations near the saturation density. The most direct experimental method for studying this property of infinite nuclear matter is to probe the isoscalar giant monopole resonance (ISGMR) in finite nuclei. This work explores the use of 6Li as a probe to study the ISGMR in several stable nuclei: 58Ni, 90Zr, 116Sn, and 208Pb, as complementary to using inelastic scattering of {\alpha}-particles, which has been used to great effect over the last several decades. Elastic and inelastic scattering data for these targets were collected with 343-MeV 6Li beams. In all nuclei studied in this work, the ISGMR strength distributions extracted from multipole decomposition analyses of the inelastic scattering spectra agree very well with the previously measured ISGMR responses from {\alpha}-particle scattering, establishing the feasibility of employing 6Li inelastic scattering in investigations of the ISGMR.

    ↳ nucl-exnucl-thPRC(2025)·4 citations
  13. 13

    Phase and equation of state of finite density QCD at lower temperature

    Etsuko Itou · Kei Iida🇯🇵 · Kotaro Murakami🇯🇵 · Daiki Suenaga

    We investigate the phase structure and the equation of state (EoS) for dense two-color QCD at low temperatures, MeV ( lattice) and MeV ( lattice). A rich phase structure below the pseudo-critical temperature as a function of quark chemical potential has been revealed. By performing MeV simulations, essentially similar results to the previous ones at MeV are obtained, but several finer understandings are achieved. Breaking of the conformal bound is also confirmed thanks to smaller statistical errors. This talk is mainly based on Refs.~\cite{Iida:2022hyy, Iida:2024irv}. It also includes related studies and subsequent developments that were not mentioned in the original papers.

    ↳ hep-lathep-phnucl-thPoS(2025)·0 citations
  14. 14

    Towards factorization with emergent scales for jets in dense media

    Balbeer Singh🇺🇸 · Varun Vaidya🇺🇸

    Employing the recently developed open quantum system Effective Field Theory framework, we investigate jet production and evolution in a dense nuclear medium in electron-ion/heavy-ion collisions. We confirm that the frequent monitoring of the jet by the medium leads to the emergence of a perturbative transverse momentum scale, often referred to as the saturation scale that necessitates further factorization to completely isolate the non-perturbative physics of the medium. A part of this goal is achieved in this paper by providing an operator definition for the broadening probability of a gluon in the medium within the Markovian approximations. We show that this distribution is (semi)universal; it depends on the angular measurement on the jet and probes both the large and small dynamics of the medium. We further elucidate all other contributions to non-perturbative physics suggesting that the parameterization of non-perturbative physics is more complex than previously assumed and outline steps required for a complete factorization of the jet production cross section.

    ↳ hep-phhep-thnucl-th4 citations
  15. 15

    Spin alignment of vector mesons in local equilibrium by Zubarev's approach

    Shi-Zheng Yang🇨🇳 · Xin-Qing Xie🇨🇳 · Shi Pu🇨🇳 · Jian-Hua Gao🇨🇳 · Qun Wang🇨🇳

    We compute the element of the spin density matrix, denoted as and called the spin alignment, up to the second order of the gradient expansion in local equilibrium by Zubarev's approach. In the first order, we obtain , meaning that the contributions from thermal vorticity and shear stress tensor are vanishing. The non-vanishing contributions to appear in the second order of gradients in the Belinfante and canonical cases. We also discuss the properties of the spin density matrix under the time reversal transformation. The effective transport coefficient for the spin alignment induced by the thermal shear stress tensor is T-odd in the first order, implying that the first order effect is dissipative.

    ↳ hep-phnucl-thPRD(2025)·11 citations
  16. 16

    Vector and Tensor Spin Polarization for Vector Bosons at Local Equilibrium

    Zhong-Hua Zhang🇨🇳 · Xu-Guang Huang🇨🇳 · Francesco Becattini🇮🇹 · Xin-Li Sheng🇮🇹

    We derive expressions for the vector and tensor components of the spin polarization of massive vector bosons at local thermodynamic equilibrium up to second order in the space-time gradients of the thermodynamic fields pertaining to the canonical stress-energy tensor and spin tensor of the free Proca field. A set of Feynman rules is devised to calculate the Wigner function and the matrix-valued spin-dependent distribution (MVSD) functions order by order in space-time gradients. Due to constraints imposed by time-reversal symmetry, the leading contribution to spin alignment - defined as the 00-component of the tensor polarization - arises from second-order terms in MVSD, for which we provide an analytic formula. We discuss the physical meaning of different contributions to vector and tensor polarization. These formulae provide a prediction of a contribution to the spin alignment which can be compared with the observations in relativistic heavy-ion collisions.

    ↳ hep-phnucl-thJHEP(2025)·16 citations
  17. 17

    Bolstering up the existence of

    Breno Agatão🇧🇷 · A. Vertel Nieto🇧🇷 · K. P. Khemchandani🇧🇷 · A. Martinez Torres🇧🇷 · Seung-il Nam🇰🇷

    We present a detailed study of the partial decay widths of a spin-parity resonance with a mass of 2070 MeV obtained from the coupled channel s wave vector-baryon , , , and dynamics. This state, which couples strongly to the channel, corresponds to a nucleon with a hidden strange quark content, in analogy to the states discovered by the LHCb collaboration, and we denote it as . A state with such a nature can decay to vector-baryon, pseudoscalar-baryon, and pseudoscalar-baryon resonance channels, involving triangular loops in the latter two cases. As we will show, the partial decay widths to pseudoscalar-baryon resonance channels, like , , , are comparable to those related to ground state baryons in the final state, like , , . In this way, reactions involving such lighter baryon resonances in the final state can be used as an alternative source of information on the properties of a with hidden strangeness.

    ↳ hep-phnucl-thPRD(2025)·0 citations
  18. 18

    Composite nature of the state

    Xian-Wei Kang🇨🇳 · Wen-Shuo Ding🇨🇳

    In 2021, LHCb collaboration reported a very narrow state in the mass spectrum just below the mass threshold. We consider the influence of the Castillejo-Dalitz-Dyson (CDD) pole in the scattering amplitude to derive a general treatment for the two-body final state interaction near its threshold. The line shape (or the energy dependent event distribution) are then obtained, where the parameters can be fixed by fitting to the experimental data on the mass spectrum. Within our method the data are quite well reproduced. The pole structure in the complex energy plane indicates that the state has a large portion of elementary degree of freedom (e.g., the compact tetraquark component) inside its hadron wave function. The compositeness as a measure of molecule component in its wave function is predicted to be . Clearly, the non-molecular component takes a non-negligible or even dominant portion.

    ↳ hep-phhep-exnucl-thCommun.Theor.Phys.(2025)·1 citation
  19. 19

    Hard Photon Triggered Jets in - and - Collisions

    C. Sirimanna🇺🇸 · Y. Tachibana🇯🇵 · A. Majumder🇺🇸 · A. Angerami🇺🇸 · R. Arora🇺🇸 · S. A. Bass🇺🇸 · Y. Chen🇺🇸 · R. Datta🇺🇸 · L. Du🇨🇦 · R. Ehlers🇺🇸 · H. Elfner🇩🇪 · R. J. Fries🇺🇸 and 40 other authors

    An investigation of high transverse momentum (high-) photon triggered jets in proton-proton (-) and ion-ion (-) collisions at and is carried out, using the multistage description of in-medium jet evolution. Monte Carlo simulations of hard scattering and energy loss in heavy-ion collisions are performed using parameters tuned in a previous study of the nuclear modification factor () for inclusive jets and high- hadrons. We obtain a good reproduction of the experimental data for photon triggered jet , as measured by the ATLAS detector, the distribution of the ratio of jet to photon (), measured by both CMS and ATLAS, and the photon-jet azimuthal correlation as measured by CMS. We obtain a moderate description of the photon triggered jet , as measured by STAR. A noticeable improvement in the comparison is observed when one goes beyond prompt photons and includes bremsstrahlung and decay photons, revealing their significance in certain kinematic regions, particularly at . Moreover, azimuthal angle correlations demonstrate a notable impact of non-prompt photons on the distribution, emphasizing their role in accurately describing experimental results. This work highlights the success of the multistage model of jet modification to straightforwardly predict (this set of) photon triggered jet observables. This comparison, along with the role played by non-prompt photons, has important consequences on the inclusion of such observables in a future Bayesian analysis.

    ↳ hep-phnucl-exnucl-thPRC(2025)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE