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Nuclear Theory·nucl-th

Thursday·July 10, 2025

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 05

    [Submitted on 8 Jul 2025] (cross-list from hep-ph)

    High-Dimensional Unfolding in Large Backgrounds

    Alexandre Falcão🇳🇴 · Adam Takacs🇩🇪

    We propose new methodologies in multi-dimensional unfolding in dense environments, and show that incorporating auxiliary observables can significantly improve performance. Our approach builds on the ML-based OmniFold algorithm, which we extend to account for background, detector acceptance, efficiency, and uncertainties, enabling its application in high-luminosity and heavy-ion collision settings. We derive this algorithm and demonstrate its mathematical and numerical equivalence to expectation-maximization and Iterative Bayesian Unfolding (IBU). We illustrate our method with a realistic jet substructure analysis incorporating both large background and detector simulation. Our analysis includes up to 18 observables, leading to significantly improved performance in the unfolding. We propose a method that integrates calibration and unfolding into a single, consistent framework, and demonstrate enhanced performance relative to traditional methods. These developments lay the groundwork for robust, high-dimensional, ML-based unfolding and calibration in complex collider environments across a wide range of analyses.

    Comments:
    Accepted version, 30 pages, 9 figures, datasets and codes at https://github.com/OmniFoldHI/OmniFoldHI
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2507.06291 [pdf]
    JHEP(2026)·7 citations
  2. 06

    [Submitted on 9 Jul 2025] (cross-list from hep-ph)

    Chiral symmetry breaking and pion condensation in the early universe

    Osvaldo Ferreira🇧🇷 · Eduardo S. Fraga🇧🇷 · Maurício Hippert🇧🇷 · Jürgen Schaffner-Bielich🇩🇪

    We determine the possible trajectories the universe may have followed in the QCD phase diagram during the QCD epoch. We focus on the roles of chiral symmetry breaking and pion condensation under high imbalances in lepton asymmetry. Adopting the quark-meson model as an effective description of QCD at finite temperature, charge and baryon chemical potentials we show that, for sufficiently large but physically motivated asymmetries, the universe may have entered the pion condensation phase through a first-order phase transition, followed by a second-order phase transition when exiting it. Such a first-order phase transition represents a new possible source of primordial gravitational waves during the QCD epoch.

    Comments:
    10 pages, 4 figures. Matches the PRD version. Typos corrected and two small new subsections added
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.06518 [pdf]
    PRD(2025)·11 citations
  3. 07

    [Submitted on 9 Jul 2025] (cross-list from hep-ph)

    Two-flavor color superconductivity in a general Nambu-Jona-Lasinio model with color and charge neutrality

    Li-Kang Yang🇨🇳 · Di-Sheng Fan🇨🇳 · Cheng-Ming Li🇨🇳 · Yong-Liang Ma🇨🇳

    By using a general NJL model including as many interaction channels as possible, and taking into account the constraints imposed by color and charge neutrality, we analyze how the different interaction channels contribute to the charge-neutral two-flavor color-superconducting matter. After taking the Fierz transformation, the number of parameters in the NJL model is reduced and thereby quark-antiquark condensates and diquark condensates are related. Through a self-consistent solution of the gap equations, we find that in addition to the diquark and vector channels, the scalar-isovector, vector-isovector, and vector-isovector-color-octet channels are also important, while other channels can be neglected. Moreover, between the normal quark matter phase and two-flavor color-superconducting phase, there is a gapless two-flavor color-superconducting phase. The fractions of quarks with different flavors and colors are calculated in both gaped and gapless two-flavor color-superconducting phases. In addition, We illustrate the phase diagrams in the diquark coupling and chemical potential plane, and discuss in detail how the dominant channels influence these phase diagrams.

    Comments:
    12 pages, 13 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.06676 [pdf]
    PRD(2025)·8 citations
  4. 08

    [Submitted on 9 Jul 2025] (cross-list from hep-th)

    Transition from weak to strong coupling in thermal gauge theories: Lessons from SYM Theory

    Berndt Müller🇺🇸

    We investigate the transition between weak and strong coupling in thermal supersymmetric Yang-Mills (SYM) theory as a function of 't Hooft coupling for several quantities of phenomenological interest for which next-to-leading order calculations are available in both regimes. We use Padé approximants to interpolate between the weak and strong coupling expansions and determine the location and width of the transition between the asymptotic regimes.

    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.06845 [pdf]
    PRD(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE