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Nuclear Theory·nucl-th

Friday·December 6, 2024

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 06

    [Submitted on 4 Dec 2024] (cross-list from hep-ph)

    Giving wake to energy-energy correlators: Hydrodynamic response on the celestial sphere

    João Barata🇨🇭 · Matvey V. Kuzmin🇷🇺 · José Guilherme Milhano🇵🇹 · Andrey V. Sadofyev🇵🇹

    The observation of the medium response generated by the propagation of high energy partons in the quark gluon plasma produced in heavy-ion collisions would provide a clear and unmistakable evidence for the hydrodynamic behavior of the bulk. Recently, it has been argued that the features of the medium's back-reaction to the jet could be cleanly imprinted in the correlations of asymptotic energy flows, in principle allowing to isolate this signal from other uncorrelated physical processes. Nonetheless, the current limited theoretical understanding of these jet observables in heavy-ion collisions constrains their applicability as probes of the medium (hydro)dynamics. In this work, we provide an analytic picture for the medium back-reaction's effect on the energy flux and two point energy correlator. We show that the medium response leads to the emergence of an universal classical scaling law, competing with the perturbative QCD contribution at large angles. Comparing the associated correlator to recent experimental measurements, we find that the observed large angle features can be qualitatively described by a purely hydrodynamically driven response and its interplay with the hard jet component.

    Comments:
    9 pages, 3 figures; v3: updated DOI
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2412.03616 [pdf]
    PRD(2025)·27 citations
  2. 07

    [Submitted on 5 Dec 2024] (cross-list from nucl-ex)

    Beta delayed neutron emission of Cd

    M. Madurga🇺🇸 · Z.Y. Xu🇺🇸 · 1 R. Grzywacz🇺🇸 · M.R. Mumpower · A. Andreyev🇬🇧 · G. Benzoni🇮🇹 · M.J.G. Borge🇨🇭 · C. Costache🇷🇴 · I. Cox🇺🇸 · S. Cupp · B. Dimitrov🇧🇬 · P. Van Duppen🇧🇪 and 45 other authors

    Using the time-of-flight technique, we measured the beta-delayed neutron emission of Cd. From our large-scale shell model (LSSM) calculation using the NLO interaction [Z.Y. Xu et al., Phys. Rev. Lett. 131, 022501 (2023)], we suggest the decay is dominated by the transformation of a neutron in the orbital, deep below the Fermi surface, into a proton in the orbital. We compare the beta-decay half-lives and neutron branching ratios of nuclei with and obtained with our LSSM with those of leading "global" models such as Finite-Range Droplet Model (FRDM). Our calculations match known half-lives and neutron branching ratios well and suggest that current leading models overestimate the yet-to-be-measured half-lives. Our model, backed by the Cd decay data presented here, offers robust predictive power for nuclei of astrophysical interest such as -process waiting points.

    Comments:
    8 pages, 6 figures
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2412.04333 [pdf]
    PRL(2026)·0 citations
  3. 08

    [Submitted on 5 Dec 2024] (cross-list from nucl-ex)

    Disentangling the influence of excitation energy and compound nucleus angular momentum on fission fragment angular momentum

    Simone Cannarozzo · Stephan Pomp · Andreas Solders · Ali Al-Adili · Zhihao Gao · Mattias Lantz · Heikki Penttilä · Anu Kankainen · Iain Moore · Tommi Eronen · Jouni Ruotsalainen · Zhuang Ge and 5 other authors

    The origin of the large angular momenta observed for fission fragments is still a question under discussion. To address this, we study isomeric yield ratios (IYR), i.e. the relative population of two or more long-lived metastable states with different spins, of fission products. We report on IYR of 17 isotopes produced in the 28 MeV -induced fission of Th at the IGISOL facility of the University of Jyväskylä. The fissioning nuclei in this reaction are U*. We compare our data to IYR from thermal neutron-induced fission of U and U, and we observe statistically significant larger IYR in the Th(,f) reaction, where the average compound nucleus (CN) spin is 7.5 , than in U(n,f), with average spins 2.5 and 3.5 , respectively. To assess the influence of the excitation energy, we study literature data of IYR from photon-induced fission reactions, and find that the IYR are independent of the CN excitation energy. We conclude that the different IYR must be explained by the different CN spin alone. This implies that the FF angular momentum only partly comes from the fission process itself, and is in addition influenced by the angular momentum present in the CN.

    Comments:
    Accepted for publication as a Letter in Physical Review C
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2412.04340 [pdf]
    PRC(2025)·5 citations
  4. 09

    [Submitted on 5 Dec 2024] (cross-list from astro-ph.HE)

    Investigating the role of nuclear parameters in Neutron Star oscillations: a model comparison

    Rajesh Maiti🇮🇳 · Debarati Chatterjee🇮🇳

    Recent studies based on the relativistic mean field (RMF) model found certain nuclear empirical parameters, in particular the nucleon effective mass, to be strongly correlated with observable properties of Neutron Stars (NSs), such as the frequencies of mode oscillations. This shows the potential to constrain the values of effective mass from future observations of modes. One of our primary goals of this work is to investigate whether such correlations are physical or an artifact of the underlying nuclear model. To test this, we perform a comparative study of the correlations between NS astrophysical observables and nuclear physics parameters using two different equation of state models based on RMF theory and non-relativistic Meta-Modelling (MM) scheme. The nuclear meta-model does not assume any underlying nuclear model and therefore allows us to test the model dependence of the results. The calculations of the mode characteristics are performed within the relativistic Cowling approximation. We use state-of-the-art nuclear microscopic calculations at low density and multi-messenger astrophysical data at high-density within a Bayesian-inspired scheme to constrain the parameter space of the nuclear models. From the posterior distribution, we probe the underlying correlations among nuclear parameters and with NS observables. We find that the correlation between the symmetry energy and its slope is physical, while that of the nucleon effective mass with NS observables is model-dependent. The study shows that the effective mass governs the high density behaviour in RMF models, while in the MM it is controlled by the higher order saturation parameters, and hence probes the possibility of constraining them from future -mode observations. The findings of this investigation are interesting both for astrophysics as well as nuclear physics communities.

    Comments:
    23 pages, 15 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2412.04373 [pdf]
    NPA(2026)·8 citations
  5. 10

    [Submitted on 5 Dec 2024] (cross-list from hep-lat)

    Block Lanczos algorithm for lattice QCD spectroscopy and matrix elements

    Daniel C. Hackett🇺🇸 · Michael L. Wagman🇺🇸

    Recent work introduced a new framework for analyzing correlation functions with improved convergence and signal-to-noise properties, as well as rigorous quantification of excited-state effects, based on the Lanczos algorithm and spurious eigenvalue filtering with the Cullum-Willoughby test. Here, we extend this framework to the analysis of correlation-function matrices built from multiple interpolating operators in lattice quantum chromodynamics (QCD) by constructing an oblique generalization of the block Lanczos algorithm, as well as a new physically motivated reformulation of the Cullum-Willoughby test that generalizes to block Lanczos straightforwardly. The resulting block Lanczos method directly extends generalized eigenvalue problem (GEVP) methods, which can be viewed as applying a single iteration of block Lanczos. Block Lanczos provides qualitative and quantitative advantages over GEVP methods analogous to the benefits of Lanczos over the standard effective mass, including faster convergence to ground- and excited-state energies, explicitly computable two-sided error bounds, straightforward extraction of matrix elements of external currents, and asymptotically constant signal-to-noise. No fits or statistical inference are required. Proof-of-principle calculations are performed for noiseless mock-data examples as well as two-by-two proton correlation-function matrices in lattice QCD.

    Comments:
    39+13 pages, 36 figures, 7 tables. v3: as published in PRD
    Subjects:
    High Energy Physics — Lattice (hep-lat); cs.NA (cs.NA); High Energy Physics — Phenomenology (hep-ph); math.NA (math.NA); Nuclear Theory (nucl-th)
    arXiv:
    2412.04444 [pdf]
    PRD(2025)·33 citations

Affiliations

first authorsco-authorsvia INSPIRE