Nuclear Theory·nucl-th

Tuesday·October 14, 2025

17 papers—9 primary·8 cross-listed

10
[Submitted on 9 Oct 2025] (cross-list from hep-ph)
Revisiting the soft-hard separation in the transverse momentum spectra of $pp$ collisions
Gábor Bíró🇭🇺 · Guy Paić🇲🇽 · Leonid Serkin🇲🇽 · Gergely Gábor Barnaföldi🇭🇺
We study the separation of soft and hard components in the transverse momentum spectra of charged particles as measured by ALICE in proton-proton collisions at $s$ = 2.76, 5.02 and 13 TeV at the LHC. The soft component is described by a Boltzmann fit, while the residual spectra are identified as a hard QCD-like fragmentation contribution. After separation, the subtracted spectra show no significant evolution in shape or peak position with multiplicity, consistent with a two-component interpretation. Mean transverse momenta for both contributions remain nearly constant across multiplicity classes, while Pythia 8 Monte Carlo simulations confirm these trends. The robustness of the decomposition is demonstrated by a comparison between simulations with and without color reconnection, yielding consistent results. The terms `soft' and `hard' are used as operational labels within this framework and should not be interpreted as uniquely identified dynamical components. Our results are consistent with the two-component description as a viable and physically motivated alternative to hydrodynamical interpretations.
Comments:
13 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2510.09692 [pdf]
EPJC(2026)·0 citations
11
[Submitted on 11 Oct 2025] (cross-list from hep-ph)
Speed of sound peak in two-color dense QCD: confronting effective models with lattice data
Arthur E.B. Pasqualotto🇧🇷 · Dyana C. Duarte🇧🇷 · Ricardo L. S. Farias🇧🇷 · Rudnei O. Ramos🇧🇷
Lattice simulations of two-color, two-flavor Quantum Chromodynamics (QCD) at finite quark chemical potential have revealed a distinctive peak structure in the sound velocity. Although chiral perturbation theory (ChPT) and the Nambu-Jona-Lasinio (NJL) model have been employed to explain this phenomenon, neither approach has fully captured the observed behavior. To address this discrepancy, we have extended the NJL framework by incorporating the Medium Separation Scheme (MSS). This approach isolates medium contributions from divergent integrals, allowing for a more accurate treatment of finite-density effects. Our results indicate a clear increase in the diquark gap ( $Δ$ ) with increasing chemical potential, consistent with what is also seen in perturbative QCD predictions at high densities. {}Furthermore, the MSS-modified NJL model successfully reproduces the observed peak in the sound velocity.
Comments:
12 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2510.10198 [pdf]
PRD(2026)·6 citations
12
[Submitted on 11 Oct 2025] (cross-list from hep-ph)
Medium modifications of $1 P$ -wave charmonia $χ_{c J} (1 P)$ in cold nuclear matter
Ze-Hua Zhang🇨🇳 · Xiang Liu🇨🇳
In this work, we employ the quark-meson coupling model to investigate the mass shifts of $1 P$ -wave charmonia $χ_{c J} (1 P)$ ( $J = 0, 1, 2$ ) in cold symmetric nuclear matter by incorporating in-medium loop contributions to the $χ_{c J} (1 P)$ self-energy within the unquenched picture. At normal nuclear matter density, we obtain significant mass reductions of about 60 MeV for the $χ_{c J} (1 P)$ states, with the $χ_{c 2} (1 P)$ mass shift primarily arising from the vector-vector loop. Our results also indicate the absence of level crossing between the in-medium $χ_{c J} (1 P)$ mass and the $D D ˉ$ mass threshold up to $ρ_{B} < 3 ρ_{0}$ -a feature that could be probed in the Compressed Baryonic Matter experiment at FAIR and the Beam Energy Scan program at RHIC.
Comments:
11 pages, 7 figures and 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2510.10200 [pdf]
PRD(2026)·2 citations
13
[Submitted on 12 Oct 2025] (cross-list from hep-ph)
Pseudoscalar heavy-quarkonium hadroproduction from nonrelativistic fragmentation at NLL/NLO $^{+}$
Francesco Giovanni Celiberto🇪🇸 · Francesca Lonigro🇪🇸
We investigate the inclusive hadroproduction of pseudoscalar heavy quarkonia, $η_{c}$ and $η_{b}$ mesons, in high-energy proton collisions. Our framework bases on the single-parton collinear fragmentation within a variable-flavor number scheme, tailored to describe the moderate to large transverse momentum regime. To this end, we construct a new set of collinear fragmentation functions, denoted as NRFF1.0, which evolve via standard DGLAP equations with a consistent treatment of flavor thresholds. Initial conditions for all parton-induced channels are computed using next-to-leading-order nonrelativistic QCD. We perform our analysis within the NLL/NLO $^{+}$ hybrid factorization framework, employing the JETHAD numerical interface together with the symJETHAD symbolic engine. These tools allow us to deliver predictions for high-energy observables sensitive to quarkonium final states at 13 TeV LHC. To the best of our knowledge, the NRFF1.0 sets represent the first-ever release of collinear fragmentation functions for heavy quarkonia that consistently includes all partonic channels within collinear factorization.
Comments:
56 pages, 18 figures, 3 tables, 402 references. Version published in Phys. Rev. D. Two sets of NLO collinear "NonRelativistic Fragmentation Functions" (NRFF1.0) for pseudoscalar quarkonia in the color-singlet S-wave channel, released in LHAPDF format at https://github.com/FGCeliberto/Collinear_FFs/. Includes LDME variations for uncertainty-ready studies
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2510.10593 [pdf]
PRD(2025)·16 citations
14
[Submitted on 12 Oct 2025] (cross-list from hep-th)
A family of three maximally symmetric boost-invariant flows in relativistic hydrodynamics
Sašo Grozdanov🇬🇧
I discuss the constructions of boost-invariant dissipative conformal hydrodynamic flows by elaborating on the geometric procedure by Gubser and Yarom, which starts from a static, maximally symmetric flow on dS $_{3} \times R$ . Three foliations of dS $_{3}$ preserve three-dimensional non-Abelian isometry groups, namely, the flat ISO(2)-invariant, the spherical (closed) SO(3)-invariant, and the hyperbolic (open) SO(2,1)-invariant slicings. I show that the fluids that preserve these symmetries, after they have been Weyl transformed to flat spacetime, give rise to three physically distinct and boost-invariant solutions of the relativistic dissipative Navier-Stokes equations: the well-known and widely studied Bjorken and Gubser flows, and a seemingly thus far unexplored solution that arises from the hyperbolic slicing of dS $_{3}$ . The new solution combines the radial expansion characteristic of the Gubser flow with the late-proper-time applicability of Bjorken's solution, and features a finite, radially bounded droplet whose expanding edge resembles a free-streaming shockwave.
Comments:
v2: 11 pages, 3 figures. Typo fixed and references added
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
2510.10769 [pdf]
4 citations
15
[Submitted on 12 Oct 2025] (cross-list from nucl-ex)
Realizing the Scientific Program with Polarized Ion Beams at EIC
Grigor Atoian🇺🇸 · Nigel Buttimore🇮🇪 · Giuseppe Ciullo🇮🇹 · Ian Cloet🇺🇸 · Marco Contalbrigo🇮🇹 · Jaydeep Datta🇺🇸 · Abhay Deshpande🇺🇸 · Shubham Dutta🇮🇳 · Oleg Eyser🇪🇬 · Muhammad Farooq🇺🇸 · Renee Fatemi🇺🇸 · Ishara Fernando🇺🇸 and 58 other authors
Polarized ion beams at the Electron Ion Collider are essential to address some of the most important open questions at the twenty-first century frontiers of understanding of the fundamental structure of matter. Here, we summarize the science case and identify polarized $^{2}$ H, $^{3}$ He, $^{6}$ Li and $^{7}$ Li ion beams as critical technology that will enable experiments which address the most important science. Further, we discuss the required ion polarimetry and spin manipulation in EIC. The current EIC accelerator design is presented. We identify a significant R\&D effort involving both national laboratories and universities that is required over about a decade to realize the polarized ion beams and estimate (based on previous experience) that it will require about 20 FTE over 10 years (or a total of about 200 FTE-years) of personnel, including graduate students, postdoctoral researchers, technicians and engineers. Attracting, educating and training a new generation of physicists in experimental spin techniques will be essential for successful realization. AI/ML is seen as having significant potential for both acceleration of R\&D and amplification of discovery in optimal realization of this unique quantum technology on a cutting-edge collider. The R\&D effort is synergistic with research in atomic physics and fusion energy science.
Comments:
47 pages, 24 figures; submitted to Phys. Rev. C (PRC)
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Accelerator Physics (physics.acc-ph); Instrumentation and Detectors (physics.ins-det)
arXiv:
2510.10794 [pdf]
PRC(2026)·7 citations
16
[Submitted on 13 Oct 2025] (cross-list from hep-ph)
QCD phase structure & equation of state: A functional perspective
Fabian Rennecke🇩🇪
The phase structure of QCD remains an open fundamental problem of standard model physics. In particular at finite density, our knowledge is limited. Yet, numerous model studies point towards a rich and complex phase diagram at large density. Functional methods like the functional renormalization group and Dyson-Schwinger equations offer a way to study hot and dense QCD matter directly from first principles. I will discuss the phase structure of QCD and its experimental signatures through the lens of these methods.
Comments:
QM2025 Proceedings; 6 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2510.11270 [pdf]
EPJ Web Conf.(2026)·7 citations
17
[Submitted on 13 Oct 2025] (cross-list from astro-ph.HE)
Proton-rich production of lanthanides: the $ν i$ process
Xilu Wang · Amol V. Patwardhan · Yangming Lin · Junbo Zheng · Michael J. Cervia · Yanwen Deng · A. Baha Balantekin · Haining Li · Ian U. Roederer · Rebecca Surman
The astrophysical origin of the lanthanides is an open question in nuclear astrophysics. Besides the widely studied $s$ , $i$ , and $r$ processes in moderately-to-strongly neutron-rich environments, an intriguing alternative site for lanthanide production could in fact be robustly $proton-rich$ matter outflows from core-collapse supernovae under specific conditions -- in particular, high-entropy winds with enhanced neutrino luminosity and fast dynamical timescales. In this environment, excess protons present after charged particle reactions have ceased can continue to be converted to neutrons by (anti-)neutrino interactions, producing a neutron capture reaction flow up to A~200. This scenario, christened the $ν i$ process in a recent paper, has previously been discussed as a possibility. Here, we examine the prospects for $ν i$ process through the lens of stellar abundance patterns, bolometric lightcurves, and galactic chemical evolution models, with a particular focus on hypernovae as candidate sites. We identify specific lanthanide signatures for which the $ν i$ process can provide a credible alternative to $r$ / $i$ processes.
Comments:
15 pages, 5 figures, v3 matches version to appear in ApJL
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2510.11467 [pdf]
ApJL(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE