Nuclear Experiment·nucl-ex

Thu·Aug 6, 2026Thursday·August 6, 2026

7 papers—3 primary·4 cross-listed

01
Directed Flow of Protons and Deuterons in Xe+Cs(I) Collisions: Preliminary BM@N Data and THESEUS Modeling
M. E. Kozhevnikova🇷🇺 · M. V. Mamaev🇷🇺 · I. A. Zhavoronkova🇷🇺 · A. V. Taranenko🇷🇺 · Yu. B. Ivanov🇷🇺
Preliminary BM@N results on the directed flow ( $v_{1}$ ) of protons and deuterons in Xe+Cs(I) collisions at 3.8 $A$ GeV are presented for the 10-40% centrality interval. The measured rapidity dependence of $v_{1}$ is compared with calculations from the THESEUS event generator, where deuterons are produced thermodynamically on an equal basis with hadrons using a late freeze-out scenario. While THESEUS well describes the proton $v_{1}$ data, it shows a slight but systematic overestimation of the deuteron flow at low and intermediate rapidities. This comparison tests both the collective dynamics of baryon-rich matter and the thermodynamic mechanism of light-nucleus formation at Nuclotron energies.
nucl-exhep-phnucl-th0 citations
02
News on charged and neutral hadron production from NA61/SHINE
Yuliia Balkova🇵🇱 · Maciej P. Lewicki🇵🇱
Strangeness production in high-energy hadronic and nuclear collisions remains a central topic in the study of strongly interacting matter under extreme conditions. The data collected by the NA61/SHINE experiment at the CERN SPS allow for a comprehensive scan of hadron production across various collision energies and system sizes. This article focuses on new results on charged and neutral hadron production in central collisions of medium-sized nuclei, such as Ar+Sc and Xe+La, in the SPS energy range. First, the energy and system-size dependence of the $K^{+} / π^{+}$ ratio is discussed, confirming the ``horn'' structure in central Pb+Pb collisions and its absence in smaller systems. Furthermore, the inverse slope parameter $T$ of kaon transverse mass (transverse momentum) spectra is analyzed, showing that intermediate-size systems reach values comparable to those observed in central Pb+Pb collisions. Second, normalized proton rapidity spectra $(d n / d y) / ⟨ W ⟩$ in central Be+Be, Ar+Sc, and Pb+Pb collisions are presented, demonstrating energy-dependent baryon transport as a function of system size. Building on this baseline, $Λ$ hyperon production in central Ar+Sc collisions is explored across SPS energies, where rapidity spectra, mean multiplicities ( $⟨ Λ ⟩$ ), and ratios to pions are compared with model predictions and existing data. Finally, an anomalous excess of charged over neutral kaons ( $R_{K} > 1$ ) in central Ar+Sc collisions is reported, highlighting a potential unexpectedly large violation of isospin symmetry.
nucl-exhep-ex0 citations
03
First Results on Nucleon Resonance Electroexcitation Amplitudes from $e p \to e^{'} π^{+} π^{-} p^{'}$ Cross Sections at $W$ from $1.56 - 1.76$ GeV and $Q^{2}$ from $2.0 - 5.0$ GeV $^{2}$
V.I.Mokeev🇺🇸 · P.Achenbach🇺🇸 · V.D.Burkert🇺🇸 · D.S.Carman🇺🇸 · R.W.Gothe🇺🇸 · E.L.Isupov🇷🇺 · K.Joo🇺🇸 · K.Neupane🇺🇸 · Y.Wunderlich🇺🇸
The first results on the electroexcitation amplitudes or the $γ_{v} p N^{*}$ electrocouplings for nucleon resonances ( $N^{*}$ s) in the third resonance region are presented. They were obtained from $π^{+} π^{-} p$ electroproduction differential cross sections measured with the CLAS detector and analyzed using the Jefferson Lab-Moscow State University (JM) reaction model. The analysis covers the invariant mass range of the final-state hadrons $W$ from 1.56 to 1.76~GeV and virtual photon four-momentum squared $Q^{2}$ from 2.0 to 5.0~GeV $^{2}$ . Consistent results on the electroexcitation amplitudes of the $N (1675) 5/ 2^{-}$ and $N (1680) 5/ 2^{+}$ obtained from independent analyses of both $π N$ and $π^{+} π^{-} p$ final states, demonstrate the capability of reaction models to extract the $γ_{v} p N^{*}$ electrocouplings for $N^{*}$ s in the third resonance region. Also, for the first time, the electrocouplings of the $Δ (1700) 3/ 2^{-}$ and $N (1720) 3/ 2^{+}$ , which predominantly decay into $π π N$ final states, have become available for $Q^{2} > 2.0$ ~GeV $^{2}$ . Finally, contributions from a new $N^{'} (1720) 3/ 2^{+}$ baryon state to the $π^{+} π^{-} p$ differential cross sections have been observed for $Q^{2} < 5.0$ ~GeV $^{2}$ . The new results on resonance electrocouplings in the third resonance region offer new opportunities to explore various aspects of the strong QCD regime responsible for the generation of nucleon excited states, in particular, shedding light on the emergence of hadron mass in connection with dynamical chiral symmetry breaking.
nucl-exhep-phnucl-th0 citations
04
Direct versus resolved photons in DPS in photoproduction on proton and nuclei
B. Blok🇩🇪 · R. Segev🇩🇪
We study the process of double parton scattering (DPS) associated with the photoproduction at a future Electron-Ion collider (EIC) and HERA. We show that in the case of the resolved photon the 1 to 2 processes lead, even at small transverse momenta of the hard processes , to the increase of the DPS by a factor of order 1.6 in the significant part of the phase space, relative to the predictions of the mean field based models . Moreover we study the kinematic region where direct photon contribution is dominant and show it s boundaries for charm and light quark jets. For charmed jets we see that the relevant region is $x_{γ} \geq 0.2 - 0.4$ . This region is even enhanced if we consider the photoproduction on the nuclei.
↳ hep-phhep-exnucl-exnucl-th1 citation
05
Quantum-information fingerprints of partial dynamical symmetry in the interacting boson model
Dhritimalya Roy🇮🇳
Partial dynamical symmetry (PDS) is an algebraic structure in which a prescribed symmetry is neither exact nor completely broken: a subset of eigenstates keeps good quantum numbers and remains solvable while the rest of the spectrum mixes. PDS is currently identified from spectroscopic data, band-head energies, level systematics, and $B (E 2)$ ratios. We ask whether it also has a purely structural signature in the eigenstates, and find that it does, though not in the magnitude of entanglement. The natural diagnostic is the variance of a symmetry Casimir, the label variance $\Var \C [G]$ , which we show coincides with a block-coherence entropy and a block impurity: all three vanish exactly when a state carries a single irreducible-representation label. Resolved state by state, this quantity is zero on the solvable subset and of order $N^{2}$ on the mixed states, at stable symmetry points and at Leviatan's first- and second-order critical points, where it takes two distinct forms set by the order of the transition. The magnitude of bipartite entanglement, by contrast, does not separate solvable from mixed states and drifts even where the labels are exact. We anchor the analysis in $^{168}$ Er, connect the block purity to the ``purity/coherence'' language of the quasi-dynamical-symmetry literature, and show the label variance is uncorrelated with multipartite entanglement and with magic. Finally we encode the model on a qubit register and prepare its solvable and mixed eigenstates variationally, as a step toward evaluating the diagnostic on a quantum device.
↳ quant-phnucl-exnucl-th0 citations
06
Type I X-Ray Burst Models With Rotation
David Martin · Jordi Jose
Type I X-ray bursts are powered by unstable thermonuclear burning on the surface of accreting neutron stars in close binary systems. These brief X-ray flashes, with light curves featuring rise times of $1 - 10$ s, durations of $10 - 100$ s, and recurrence periods of hours to days, represent the most frequent stellar explosions in our Galaxy. With typical energies of $\sim 1 0^{39} - 1 0^{40}$ erg, they rank among the most powerful astrophysical transients after supernovae and classical novae. To date, roughly 120 bursting X-ray binaries have been identified in the Milky Way. Several studies have been conducted to characterize the dynamics of these events, with emphasis on reproducing the observed recurrence periods and light curve shapes. In this paper we show, for the first time, that rotation is a key factor shaping the properties of Type I X-ray bursts in rapidly spinning systems. The inclusion of centrifugal forces, together with a suite of rotationally-induced mixing mechanisms, such as meridional circulation and shear-induced turbulent diffusion, reduce surface gravity, shortening the recurrence times and lowering burst energies. Rotation also modifies the extent of the nuclear activity during these events and affects the morphology of their light curves, which are distinctly broader for rapidly rotating neutron stars.
↳ astro-ph.HEastro-ph.SRnucl-exApJ(2026)·0 citations
07
Bayesian Inference of fine-features of dense matter EOS from future high-precision data of neutron star radii
Bao-An Li🇺🇸 · Xavier Grundler🇺🇸 · Wen-Jie Xie🇨🇳 · Nai-Bo Zhang🇨🇳
Future high-precision X-ray and gravitational wave observatories are expected to measure the radii of neutron stars (NSs) with an accuracy better than about 0.1 km. However, it remains unclear what particular aspects of the Equation of State (EOS) and to what precision they will be better constrained. Within a Bayesian framework using a meta-model EOS and mock high-precision NS data, the posterior probability distribution functions (PDFs) of NS matter EOS parameters for both hadronic and quark phases and the transition between them were recently studied. We report here a few highlights of these studies.
↳ astro-ph.HEnucl-exnucl-thEPJ Web Conf.(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Directed Flow of Protons and Deuterons in Xe+Cs(I) Collisions: Preliminary BM@N Data and THESEUS Modeling

News on charged and neutral hadron production from NA61/SHINE

First Results on Nucleon Resonance Electroexcitation Amplitudes from ep→e′π+π−p′ Cross Sections at W from 1.56−1.76 GeV and Q2 from 2.0−5.0 GeV2

Direct versus resolved photons in DPS in photoproduction on proton and nuclei

Quantum-information fingerprints of partial dynamical symmetry in the interacting boson model

Type I X-Ray Burst Models With Rotation

Bayesian Inference of fine-features of dense matter EOS from future high-precision data of neutron star radii

Affiliations

First Results on Nucleon Resonance Electroexcitation Amplitudes from $e p \to e^{'} π^{+} π^{-} p^{'}$ Cross Sections at $W$ from $1.56 - 1.76$ GeV and $Q^{2}$ from $2.0 - 5.0$ GeV $^{2}$