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Nuclear Theory·nucl-th

Wednesday·April 2, 2025

20 papers—9 primary·11 cross-listed

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  1. 10

    [Submitted on 7 Feb 2025] (cross-list from hep-ph)

    Short Note on Spin Magnetization in QGP

    Andrew Steinmetz🇺🇸 · Johann Rafelski🇺🇸

    We outline the theory of spin magnetization applicable to the QGP (quark-gluon plasma) epoch of the Universe. We show that a fully spin-polarized single flavor up-quark gas could generate a cosmic magnetic fields in excess of Tesla, far in excess of a possible upper limit to the primordial field. The complete multi component ferro-magnetized primordial fermion gas we consider consists of (five) nearly free electrically charged quarks, and leptons (electrons, muons, tau). We present details of how the magnetization is obtained using a grand partition function approach and point to the role of the nonrelativistic particle component. In the range of temperature 150 MeV to 500 MeV our results are also of interest to laboratory QGP experiments. We show that the required polarization capable to explain large scale structure magnetic fields observed has scaling in the limit of high , and could be very small, at pico-scale. In the other limit, as temperature decreases in the expanding Universe, we show that any magnetic fields present before hadronization can be carried forward to below quark confinement condition temperature by polarization of electrons and muons.

    Comments:
    10 pages, 1 figure, revised and accepted for special issue of EPJ ST "Particles and Plasmas" edited by Tamás Sándor Biró, Gergely Gábor Barnaföldi and Gábor Bíró
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph)
    arXiv:
    2502.05052 [pdf]
    Eur.Phys.J.ST(2025)·0 citations
  2. 11

    [Submitted on 27 Mar 2025] (cross-list from hep-ph)

    Neutrino Theory in the Precision Era

    Asmaa Abada🇫🇷 · Gabriela Barenboim🇪🇸 · Toni Bertólez-Martínez🇪🇸 · Sandipan Bhattacherjee🇮🇳 · Sara Bolognesi🇫🇷 · Patrick D. Bolton🇸🇮 · Nilay Bostan🇺🇸 · Gustavo C. Branco🇵🇹 · Sabya Sachi Chatterjee🇩🇪 · Adriano Cherchiglia🇧🇷 · Marco Chianese🇮🇹 · B. A. Couto e Silva🇫🇮 and 67 other authors

    This document summarises discussions on future directions in theoretical neutrino physics, which are the outcome of a neutrino theory workshop held at CERN in February 2025. The starting point is the realisation that neutrino physics offers unique opportunities to address some of the most fundamental questions in physics. This motivates a vigorous experimental programme which the theory community fully supports. \textbf{A strong effort in theoretical neutrino physics is paramount to optimally take advantage of upcoming neutrino experiments and to explore the synergies with other areas of particle, astroparticle, and nuclear physics, as well as cosmology.} Progress on the theory side has the potential to significantly boost the physics reach of experiments, as well as go well beyond their original scope. Strong collaboration between theory and experiment is essential in the precision era. To foster such collaboration, \textbf{we propose to establish a CERN Neutrino Physics Centre.} Taking inspiration from the highly successful LHC Physics Center at Fermilab, the CERN Neutrino Physics Centre would be the European hub of the neutrino community, covering experimental and theoretical activities.

    Comments:
    summary document of the CERN Neutrino Platform Pheno Week 2025 as input to the European Strategy for Particle Physics 2025 update; 13 pages
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2504.00014 [pdf]
    3 citations
  3. 12

    [Submitted on 31 Mar 2025] (cross-list from hep-ph)

    Transverse Energy--Energy Correlators at Small for Photon--Hadron Production

    Zhong-Bo Kang🇺🇸 · Robert Kao🇺🇸 · Meijian Li🇪🇸 · Jani Penttala🇺🇸

    We study the transverse energy--energy correlator (TEEC) observable in photon--hadron and photon--jet production in p+p and p+A collisions at small . We derive the relevant expressions in the high-energy limit of the scattering where the dipole picture is applicable and show how the dependence on the fragmentation function of the hadron cancels due to the momentum-sum rule. The nonperturbative scattering with the target nucleus is expressed in terms of the dipole amplitude, which also describes nonlinear gluon saturation effects. The TEEC observable is computed in the RHIC and LHC kinematics, and we show that it can be sensitive to the dipole amplitude, making it a potentially good observable for studying saturation effects.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2504.00069 [pdf]
    PRD(2025)·9 citations
  4. 13

    [Submitted on 31 Mar 2025] (cross-list from hep-ph)

    Open quantum system approach to inclusive jet production in heavy-ion collisions

    Yacine Mehtar-Tani🇺🇸 · Felix Ringer🇺🇸 · Balbeer Singh🇺🇸 · Varun Vaidya🇺🇸

    We derive a factorization formula for inclusive jet production in heavy-ion collisions using the tools of Effective Field Theory (EFT). We show how physics at widely separated scales in this process can be systematically separated by matching to EFTs at successively lower virtualities. Owing to a strong scale separation, we recover a vacuum-like DGLAP evolution above the jet scale, while the additional low-energy scales induced by the medium effectively probe the internal structure of the jet. As a result, the cross section can be written as a series with an increasing number of subjets characterized by perturbative matching coefficients each of which is convolved with a {\it distinct} function. These functions encode broadening, medium-induced radiations as well as quantum interference such as the Landau-Pomeranchuk-Migdal effect and color coherence dynamics to all orders in perturbation theory. As a first application of this EFT framework, we investigate the case of an unresolved jet and show how the cross section can be factorized and fully separate the jet dynamics from the universal physics of the medium. To compare to the existing literature, we explicitly compute the medium jet function at next-to-leading order in the coupling and leading order in medium opacity.

    Comments:
    63 pages, 16 figures and three appendix
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2504.00101 [pdf]
    JHEP(2026)·11 citations
  5. 14

    [Submitted on 31 Mar 2025] (cross-list from astro-ph.HE)

    Properties of the Object HESS J1731-347 as a Twin Compact Star

    David E. Alvarez-Castillo🇵🇱

    By consideration of the Compact object HESS J1731-347 as a hybrid twin compact star, i.e., a more compact star than its hadronic twin of the same mass, its stellar properties are derived. Besides showing that the properties of compact stars in this work are in good agreement with state-of-the-art constraints both from measurements carried out in laboratory experiments as well as by multi-messenger astronomy observations, the realization of an early strong hadron-quark first order phase transition as implied by the twins is discussed.

    Comments:
    37 pages, 14 figures, 7 tables. Matches the published version
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2504.00240 [pdf]
    Universe(2025)·6 citations
  6. 15

    [Submitted on 31 Mar 2025] (cross-list from hep-ex)

    The Short-Baseline Near Detector at Fermilab

    SBND Collaboration: R. Acciarri🇺🇸 · L. Aliaga-Soplin🇺🇸 · O. Alterkait🇺🇸 · R. Alvarez-Garrote🇪🇸 · D. Andrade Aldana🇺🇸 · C. Andreopoulos🇬🇧 · A. Antonakis🇺🇸 · L. Arellano🇬🇧 · W. Badgett🇺🇸 · S. Balasubramanian🇺🇸 · A. Barnard · V. Basque🇺🇸 and 185 other authors

    SBND is a 112 ton liquid argon time projection chamber (LArTPC) neutrino detector located 110 meters from the Booster Neutrino Beam (BNB) target at Fermilab. Its main goals include searches for eV-scale sterile neutrinos as part of the Short-Baseline Neutrino (SBN) program, other searches for physics beyond the Standard Model, and precision studies of neutrino-argon interactions. In addition, SBND is providing a platform for LArTPC neutrino detector technology development and is an excellent training ground for the international group of scientists and engineers working towards the upcoming flagship Deep Underground Neutrino Experiment (DUNE). SBND began operation in July 2024, and started collecting stable neutrino beam data in December 2024 with an unprecedented rate of ~7,000 neutrino events per day. During its currently approved operation plans (2024-2027), SBND is expected to accumulate nearly 10 million neutrino interactions. The near detector dataset will be instrumental in testing the sterile neutrino hypothesis with unprecedented sensitivity in SBN and in probing signals of beyond the Standard Model physics. It will also be used to significantly advance our understanding of the physics of neutrino-argon interactions ahead of DUNE. After the planned accelerator restart at Fermilab (2029+), opportunities are being explored to operate SBND in antineutrino mode in order to address the scarcity of antineutrino-argon scattering data, or in a dedicated beam-dump mode to significantly enhance sensitivity to searches for new physics. SBND is an international effort, with approximately 40% of institutions from Europe, contributing to detector construction, commissioning, software development, and data analysis. Continued European involvement and leadership are essential during SBND's operations and analysis phase for both the success of SBND, SBN and its role leading up to DUNE.

    Comments:
    Input to the European Strategy for Particle Physics 2026 Update
    Subjects:
    High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2504.00245 [pdf]
    23 citations
  7. 16

    [Submitted on 31 Mar 2025] (cross-list from hep-ph)

    H and He nuclei production in a combined thermal and coalescence framework for heavy-ion collisions in the few-GeV energy regime

    Zbigniew Drogosz🇵🇱 · Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱 · Nikodem Witkowski🇵🇱

    A thermal model describing hadron production in heavy-ion collisions in the few-GeV energy regime is combined with the idea of nucleon coalescence to make predictions for the H and He nuclei production. A realistic parametrization of the freeze-out conditions is used, which reproduces well the spectra of protons and pions. It also correctly predicts the deuteron yield that agrees with the experimental value. The predicted yields of H and He appear to be smaller by about a factor of two compared to the experimental results. The model predictions for the spectra can be compared with future experimental data.

    Comments:
    19 pages, 5 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2504.00283 [pdf]
    CPC(2026)·4 citations
  8. 17

    [Submitted on 1 Apr 2025] (cross-list from hep-lat)

    Three-hadron dynamics from lattice QCD

    Fernando Romero-López🇨🇭

    Three-hadron spectroscopy is a key frontier in our understanding of the hadron spectrum. In recent years, significant formal and numerical advances have paved the way for studying three-hadron processes directly from lattice QCD, with outstanding applications including the Roper resonance and the doubly charmed tetraquark. This requires theoretical frameworks that relate finite-volume energies to infinite-volume three-particle scattering amplitudes. In this contribution, I discuss recent progress in formulating such frameworks for generic three-hadron systems, and present numerical results for three-meson systems at maximal isospin with physical quark masses, as well as our recent investigation of the three-body dynamics of the doubly charmed tetraquark, .

    Comments:
    20 pages, 9 figures. Plenary talk at Chiral Dynamics 2024
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2504.00586 [pdf]
    PoS(2026)·4 citations
  9. 18

    [Submitted on 1 Apr 2025] (cross-list from hep-lat)

    Selected topics on the QCD phase diagram at finite temperature and density

    Christian Schmidt🇩🇪

    We will report recent progress on the QCD phase diagram at finite temperature and density. In particular, we discuss the universal scaling of the chiral transition in the limit of two massless quarks and one strange quark. We also discuss influence of other control parameter as chemical potentials, external magnetic field strength and number of quark flavors on the chiral transition. From calculations of Taylor expansion coefficients of the pressure w.r.t the baryon chemical potential and at imaginary chemical potential, we discuss estimates of the QCD critical point. Those estimates make use of the universal scaling ansatz of the Lee-Yang edge singularity.

    Comments:
    plenary talk at Lattice 2024, 14 pages, 10 figures
    Subjects:
    High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2504.00629 [pdf]
    PoS(2025)·11 citations
  10. 19

    [Submitted on 1 Apr 2025] (cross-list from hep-ph)

    Lepton-proton two-photon exchange with improved soft-photon approximation including proton's structure effects in HBPT

    Rakshanda Goswami🇮🇳 · Pulak Talukdar🇮🇳 · Bhoomika Das🇮🇳 · Udit Raha🇮🇳 · Fred Myhrer🇺🇸

    We present an improved evaluation of the two-photon exchange correction to the unpolarized lepton-proton elastic scattering process at very low-energies relevant to the MUSE experiment, where only the dominant intermediate elastic proton is considered. We employ the framework of heavy baryon chiral perturbation theory and invoke the soft-photon approximation in order to reduce the intricate 4-point loop-integrals into simpler 3-point loop-integrals. In the present work, we adopt a more robust methodology compared to an earlier work along the same lines for analytically evaluating the loop-integrations, and incorporate important corrections at next-to-next-to-leading order. These include the proton's structure effects which renormalize the proton-photon interaction vertices and the proton's propagator. Finally, our results allow a model-independent estimation of the charge asymmetry for the scattering of unpolarized massive leptons and anti-leptons.

    Comments:
    29 pages, 9 figures, article
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2504.00706 [pdf]
    0 citations
  11. 20

    [Submitted on 1 Apr 2025] (cross-list from hep-ph)

    Transverse spin polarization as a novel probe of medium-induced transverse-momentum-broadening effect

    Xin-yu Qin🇨🇳 · Yu-Kun Song🇨🇳 · Shu-yi Wei🇨🇳

    The transverse polarization of hyperons within unpolarized jets originates from the transverse-momentum-dependent (TMD) fragmentation function . In the vacuum environment, the QCD evolution of this TMD fragmentation function is governed by the Collins-Soper equation. However, in the presence of the quark-gluon plasma (QGP) medium, the jet-medium interaction induces a transverse-momentum-broadening effect that modifies the QCD evolution. As a result, the transverse spin polarization of hyperons in relativistic heavy-ion collisions differs from that in collisions. We demonstrate that this difference serves as a sensitive probe for studying jet-medium interaction, offering a novel perspective through the spin degree of freedom.

    Comments:
    14 pages, 6 figures; additional references added; both transverse momentum broadening and energy loss effects are considered
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2504.00739 [pdf]
    PRD(2026)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE