Nuclear Theory·nucl-th

Tuesday·October 7, 2025

8 papers—1 primary·7 cross-listed

02
[Submitted on 3 Oct 2025] (cross-list from hep-ph)
First Demonstration that Quark-Gluon Plasma has a Nonzero Resolution Length
Arjun Srinivasan Kudinoor🇺🇸 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸
We report on our investigation in arXiv:2509.08881 of how recent jet substructure measurements constrain the resolution length $L_{res}$ of the quark-gluon plasma formed in heavy-ion collisions. $L_{res}$ is defined such that high-energy partons within a jet shower are resolved by the medium if and only if they are separated by a distance greater than $L_{res}$ . Using the Hybrid Model, we reproduce ALICE data on the scaled Soft Drop angle $θ_{g}$ for $R = 0.2$ charged-particle jets and ATLAS data on the Hard Group angle $Δ R_{12}$ for $R = 1$ jets reclustered from skinny $R = 0.2$ inclusive subjets. We find that the narrowing of the $θ_{g}$ -distribution in PbPb collisions observed by ALICE and the suppression of $R = 1$ jets with multiple skinny subjets in PbPb collisions observed by ATLAS rule out $L_{res} = \infty$ , where each entire parton shower loses energy to the plasma coherently as if it were a single colored object. We then compare Hybrid Model calculations to ATLAS measurements of $R_{AA}$ of $R = 1$ jets reclustered from $R = 0.2$ subjets, as a function of the Soft Drop angle $d R_{12}$ obtained by grooming all charged-particle tracks associated with each $R = 1$ jet. We demonstrate, for the first time, that the ATLAS data is inconsistent with $L_{res} = 0$ , where the plasma resolves every splitting in a parton shower. Our results agree best with the data when QGP possesses a finite, nonzero $L_{res} \sim (1 - 2) / (π T)$ .
Comments:
11 pages, 4 figures. Contribution to the XQCD 2025 Proceedings. Based on arXiv:2509.08881
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2510.03390 [pdf]
0 citations
03
[Submitted on 4 Oct 2025] (cross-list from hep-ph)
Effects of hadronic molecule $N (2080) 3/ 2^{-}$ on $K^{*+} Λ$ photoproduction
Wen-Ya Tian🇨🇳 · Neng-Chang Wei🇨🇳 · Yu-Fei Wang🇨🇳 · Fei Huang🇨🇳 · Bing-Song Zou🇨🇳
In our previous work [Phys. Rev. C {\bf 101}, 014003 (2020)], we have analyzed all available data on differential cross sections and spin density matrix elements for the $γ p \to K^{*+} Λ$ reaction using an effective Lagrangian approach. There, the $t$ -channel $K$ , $K^{*}$ , and $κ$ exchanges, the $u$ -channel $Λ$ , $Σ$ , and $Σ^{*}$ exchanges, the $s$ -channel $N$ , $N (2060) 5/ 2^{-}$ , and $N (2000) 5/ 2^{+}$ exchanges, and the interaction current were taken into account in constructing the reaction amplitudes. It was found that, overall, the agreement of the theoretical results with the corresponding data is fairly good. However, noticeable discrepancies between the model results and the data on spin density matrix elements $ρ_{00}$ are still observed in the center-of-mass energy region around $W \approx 2.08$ GeV, indicating the need for additional reaction mechanisms. On the other hand, the hidden-strange pentaquark-like state $N (2080) 3/ 2^{-}$ , which is proposed to be a $K^{*} Σ$ molecular state as the strange partner of $P_{c} (4457)$ hadronic molecule, has been found to play quite active roles in reproducing the data for $K^{*+} Σ^{0}$ , $K^{* 0} Σ^{+}$ , and $ϕp$ photoproduction reactions. Based on these observations, in the present work, we reanalyze the data for the $γ p \to K^{*+} Λ$ reaction by incorporating the pentaquark-like state $N (2080) 3/ 2^{-}$ in our previously proposed model. The results show that with the inclusion of the contributions of $N (2080) 3/ 2^{-}$ , the quality of the theoretical description of the $γ p \to K^{*+} Λ$ data can be considerably improved.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2510.03673 [pdf]
PRC(2025)·4 citations
04
[Submitted on 5 Oct 2025] (cross-list from quant-ph)
Quantum computing for heavy-ion physics: near-term status and future prospects
João Barata🇨🇭
We discuss recent advances in applying Quantum Information Science to problems in high-energy nuclear physics. After outlining key developments, open challenges, and emerging connections between these disciplines, we highlight recent results on the study of matter states, hard probes, and spin correlations using novel quantum technologies. This work summarizes the corresponding presentation delivered at the Quark Matter 2025 conference in Frankfurt, Germany.
Comments:
Proceedings for Quark Matter 2025 Frankfurt; v2: updated references
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2510.04207 [pdf]
EPJ Web Conf.(2026)·1 citation
05
[Submitted on 6 Oct 2025] (cross-list from nucl-ex)
$β$ -delayed proton pandemonium: A first detailed $^{31}$ Cl( $β p γ$ ) $^{30}$ P decay scheme
Tamas Budner (1 and 2)🇺🇸 · Moshe Friedman (3 and 4)🇺🇸 · Lijie Sun (2 and 5)🇺🇸 · Christopher Wrede (1 and 2)🇺🇸 · B. Alex Brown (1 and 2)🇺🇸 · David Pérez-Loureiro (3)🇺🇸 · Jason Surbrook (1 and 2)🇺🇸 · Alexander Adams (1 and 2)🇺🇸 · Yassid Ayyad (3 and 6)🇺🇸 · Daniel W. Bardayan (7)🇺🇸 · Kyungyuk Chae (8)🇰🇷 · Alan A. Chen (9)🇨🇦 and 11 other authors
Positron decays of proton-rich nuclides exhibit large $Q$ values, producing complex cascades which frequently involve various radiations, including protons and $γ$ rays. Often, only one of the two is measured in a single experiment, limiting the accuracy and completeness of the decay scheme. An example is $^{31}$ Cl, for which protons and $γ$ rays have been measured separately in detail but never with substantial sensitivity to proton- $γ$ coincidences. We provide detailed measurements of $^{31}$ Cl $β$ -delayed proton decay including $β$ - $p$ - $γ$ sequences, extract spectroscopic information on $^{31}$ S excited states as well as their $β^{+}$ feedings, and compare to shell-model calculations. A fast fragmented beam of $^{31}$ Cl provided by the National Superconducting Cyclotron Laboratory (NSCL) was deposited in the Gaseous Detector with Germanium Tagging (GADGET) system. GADGET's gas-filled Proton Detector was used to detect $β$ -delayed protons, and the Segmented Germanium Array (SeGA) was used to detect $β$ -delayed $γ$ rays. As many as 20 previously unobserved $β$ -delayed proton transitions are reported, most of which populate excited states of $^{30}$ P. The first detailed $^{31}$ Cl( $β p γ$ ) $^{30}$ P decay scheme is presented, including updated $β$ -delayed proton energies and intensities, as well as several new $^{31}$ S levels. Improved agreement is found with theoretical calculations of the Gamow-Teller strengths $B (GT)$ for $^{31}$ S excitation energies $7.5 < E_{x} < 9.5$ MeV. The present work demonstrates that the ability to detect $β$ -delayed protons and $γ$ rays in coincidence is essential for accurate positron decay schemes to compare with nuclear structure theory. This phenomenon for $β$ -delayed protons resembles the pandemonium effect originally introduced for $β$ -delayed $γ$ rays.
Comments:
17 pages, 13 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2510.04456 [pdf]
PRC(2026)·0 citations
06
[Submitted on 6 Oct 2025] (cross-list from hep-ph)
Overview of the latest developments in understanding the initial state and thermalization
Kirill Boguslavski🇫🇷
A proper description of the non-equilibrium matter preceding the quark-gluon plasma (QGP) in heavy-ion collisions and its observable consequences remain a major theoretical challenge, while at the same time offering new opportunities for experimental exploration. In these proceedings, I provide an overview of studies presented in talks and posters at Quark Matter 2025 on this topic. We will focus on the latest developments regarding the features and the numerical description of the non-equilibrium pre-QGP matter, as well as the potential to use hard probes as a means to study the hydrodynamization dynamics of the QCD plasma.
Comments:
6 pages, 2 figures. Plenary talk on initial state and thermalization at Quark Matter 2025 (6-12 April 2025, Frankfurt, Germany)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2510.04661 [pdf]
EPJ Web Conf.(2026)·0 citations
07
[Submitted on 6 Oct 2025] (cross-list from hep-ph)
Barnett effect as a new source of magnetic field in heavy-ion collisions
Dushmanta Sahu🇲🇽
The Barnett effect is a fundamental magnetomechanical phenomenon in which a ferromagnetic material becomes magnetized under rotation. Using a hadron resonance gas (HRG) model under rigid rotation, we compute the Barnett magnetization ( $M_{Barnett}$ ) and show that it produces a magnetic field ( $B_{ind}$ ) comparable in magnitude to the well-known external field ( $B_{ext}$ ) from spectator protons at low energy heavy-ion collisions. This finding establishes the Barnett effect as a previously overlooked but essential source of magnetization and magnetic field in the heavy-ion collisions, with profound implications for understanding spin dynamics and anomalous transport in quantum chromodynamics under extreme rotation.
Comments:
6 pages, 3 captioned figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2510.05066 [pdf]
PLB(2026)·5 citations
08
[Submitted on 6 Oct 2025] (cross-list from nucl-ex)
Valence $1 s - 0 d$ proton vacancy of the $^{32}$ Si ground state
N. Watwood🇺🇸 · C. R. Hoffman🇺🇸 · B. P. Kay🇺🇸 · I. A. Tolstukhin🇺🇸 · J. Chen🇨🇳 · T. L. Tang🇺🇸 · D. Bazin🇺🇸 · Y. Ayyad🇪🇸 · S. Beceiro-Novo🇪🇸 · S. J. Freeman🇬🇧 · L. P. Gaffney🇬🇧 · R. Garg🇺🇸 and 13 other authors
The $^{32}$ Si( $^{3}$ He, $d$ ) $^{33}$ P reaction was studied in inverse kinematics at 6.3~MeV/ $u$ . States in $^{33}$ P corresponding to the proton $1 s - 0 d$ single-particle orbitals were identified up to $\sim$ 4.5 MeV in excitation energy. The ( $^{3}$ He, $d$ ) spectroscopic factors were determined from Distorted Wave Born Approximation calculations. When combined with complementary neutron-adding data, the $1 s - 0 d$ proton vacancies in the $^{32}$ Si ground state were extracted. In conjunction with a re-analysis of data from previous single-particle measurements, the trends in proton and neutron vacancy were explored across the $^{28, 30, 32, 34}$ Si isotopes. Both proton and neutron vacancy data show gradual changes in their occupancies. The proton $1 s_{1/2}$ orbitals in $^{32}$ Si and $^{34}$ Si are both consistent with being empty. The ground-state nucleon distributions are described by shell-model calculations constrained to the $1 s - 0 d$ model space.
Comments:
9 pages, 5 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2510.05073 [pdf]
PRC(2025)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

First Demonstration that Quark-Gluon Plasma has a Nonzero Resolution Length

Effects of hadronic molecule N(2080)3/2− on K∗+Λ photoproduction

Quantum computing for heavy-ion physics: near-term status and future prospects

β-delayed proton pandemonium: A first detailed 31Cl(βpγ)30P decay scheme

Overview of the latest developments in understanding the initial state and thermalization

Barnett effect as a new source of magnetic field in heavy-ion collisions

Valence 1s−0d proton vacancy of the 32Si ground state

Affiliations

Effects of hadronic molecule $N (2080) 3/ 2^{-}$ on $K^{*+} Λ$ photoproduction

$β$ -delayed proton pandemonium: A first detailed $^{31}$ Cl( $β p γ$ ) $^{30}$ P decay scheme

Valence $1 s - 0 d$ proton vacancy of the $^{32}$ Si ground state