Nuclear Theory·nucl-th

Tuesday·July 8, 2025

19 papers—7 primary·12 cross-listed

01
[Submitted on 4 Jul 2025]
Nuclear $β^{-}$ -decay with statistical de-excitation
M. R. Mumpower · T. Kawano · O. Korobkin · G. W. Misch · T. M. Sprouse
The accurate description of nuclear $β^{-}$ -decay has far-reaching consequences for applications spanning nuclear reactors to the creation of heavy elements in astrophysical environments. We present the nuclear particle spectra associated with the $β$ -decay of neutron-rich nuclei calculated with the well benchmarked coupled Quasi-particle Random Phase Approximation and Hauser-Feshbach (QRPA+HF) model. This approach begins with the population of the daughter nucleus via semi-microscopic Gamow-Teller or First-Forbidden strength distributions (QRPA) and follows the statistical de-excitation (HF) until the initial available excitation energy is exhausted. At each stage of de-excitation the emission by neutrons and $γ$ -rays is considered obeying quantum mechanical selection rules. For completeness we also provide parsed Auger and Internal Conversion (IC) electron spectra from Evaluated Nuclear Data Files (ENDF). Our results are tabulated and provided in parsable ASCII formatted tables that are suitable for inclusion in various applications.
Comments:
18 pages of text; 150 page table; 7 figures; published in ADNDT
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.03592 [pdf]
Atom.Data Nucl.Data Tabl.(2025)·3 citations
02
[Submitted on 4 Jul 2025]
Equation-of-State Independent Relations in Rapidly Rotating Hybrid Stars
Sujan Kumar Roy🇮🇳
We study 22 hadronic and 100 hybrid equations of state (EoSs) that allow for heavy baryons and deconfined quark matter at high densities, aiming to establish quasi-universal relations for both slowly and rapidly rotating neutron stars. All EoSs are consistent with current observational constraints, including NICER and GW170817. Our results confirm that the I-Love-Q and I-C-Q relations remain approximately EoS-insensitive across this broad EoS set, with deviations typically within 10\% for hadronic stars and up to 20\% for those with complex core compositions. These relations are extended to include low-mass neutron stars such as HESS J1731-347, and to stars with general core compositions--nucleonic, hyperonic (full baryon octet), and quark matter. The analysis underscores both the robustness and the limitations of universal relations when applied to compact stars with exotic degrees of freedom and rapid rotation.
Comments:
Accepted for publication in JCAP
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.03664 [pdf]
JCAP(2025)·1 citation
03
[Submitted on 4 Jul 2025]
$Λ$ -deuteron momentum correlation functions incorporating deuteron breakup contributions in Faddeev formulation
M. Kohno🇯🇵 · H. Kamada🇯🇵
The effects of the deuteron breakup are estimated for the $Λ$ -deuteron momentum correlation function. Faddeev amplitudes in calculating low-energy $Λ$ -deuteron scattering can provide not only the elastic scattering part but also breakup wave functions in the incident and the rearrangement channels. Calculations are carried out using nucleon-nucleon (NN) and hyperon-nucleon (YN) interactions parametrized in chiral effective field theory. The effects of the breakup in the incident channel are found to be marginally insignificant. Those of the rearrangement channel are not negligible, but not large when the source radius is larger than 2.5 fm. Nevertheless, it is worthwhile to have the information on the magnitude of these effects in analyzing the experimental data.
Comments:
8pages, 5 figures, Correction of Eq.(A1)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.03792 [pdf]
PRC(2025)·4 citations
04
[Submitted on 4 Jul 2025]
Variational Theory and Parquet Diagrams for Nuclear Systems: A Comprehensive Study of Neutron Matter
Eckhard Krotscheck · Jiawei Wang
To deal with the problem of realistic nuclear interactions we have combined techniques of the Jastrow-Feenberg variational method and the local parquet-diagram theory. In the language of diagrammatic perturbation theory, ``commutator diagrams'' can be identified with non-parquet diagrams. We examine the physical processes described by these terms and include the relevant diagrams in a way that is suggested by the Jastrow-Feenberg approach. We show that the corrections from non-parquet contributions are, at short distances, larger than all other many-body effects. We examine here neutron matter as a prototype of systems with state-dependent interactions. Calculations are carried out for neutrons interacting via the so-called $v_{8}$ version of four popular interactions. We determine the structure and effective interactions and apply the method to the calculation of the energetics, structure and dynamic properties such as the single-particle self-energy and the dynamic response functions as well as BCS pairing in both singlet and triplet states. We find that many-body correlations lead to a strong reduction of the spin-orbit interaction, and, therefore, to a suppression of the $^{3} P_{2}$ and $^{3} P_{2}$ - $^{3} F_{2}$ gaps. We also find pairing in $^{3} P_{0}$ states; the strength of the pairing gap depends sensitively on the potential model employed.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.03825 [pdf]
EPJA(2026)·0 citations
05
[Submitted on 6 Jul 2025]
Particle species dependence of elliptic flow fluctuations in Pb-Pb collisions at LHC energies in a multiphase transport model
Jie Wan🇨🇳 · Chun-Zheng Wang🇨🇳 · Yu-Gang Ma🇨🇳 · Qi-Ye Shou🇨🇳 · Song Zhang🇨🇳
The fluctuations of elliptic flow (\vtwo) in relativistic heavy-ion collisions offer a powerful tool to probe the collective behavior and transport properties of the quark-gluon plasma (QGP). The dependence of these fluctuations on particle species further sheds light on the hadronization mechanism. At LHC energies, the ALICE experiment has measured $v_{2}$ fluctuations for charged pions, kaons, and (anti-)protons via the ratio of \vtwo measured with respect to the spectator plane (\vtwosp) and from the four-particle cumulants (\vtwofour). However, the observed dependencies on transverse momentum and particle type remain not fully understood. In this study, we perform a phenomenological investigation using a multiphase transport (AMPT) model, which allows us to trace the full evolution of flow fluctuations intertwined with the quark coalescence. The results qualitatively reproduce the ALICE measurements and offer deeper insights into the transport dynamics and hadronization of the QGP.
Comments:
9 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.04497 [pdf]
PRC(2025)·1 citation
06
[Submitted on 7 Jul 2025]
From Nuclear Matter with Quenched $g_{A}$ to Compact-Star Matter with a Signal for Emergent Hidden Scale Symmetry
Mannque Rho🇫🇷
An ``unorthodox" idea is developed that the long-standing mystery in nuclear physics of the effective axial-current coupling constant in nuclei, $g_{A}^{eff} \approx 1$ , could be interpreted in terms of an emerging hidden scale symmetry in dense compact-star matter. Arguments are presented using an effective field theory anchored on a renormalization-group approach to interacting baryons on the Fermi surface coupled with hidden symmetric heavy mesonic degrees of freedom that enables one to go beyond Weinberg's nuclear effective field theory involving nucleon and pion fields only, referred hereon to as $χ$ EFT $_{π}$ . Both hidden local and scale symmetries, the former involving the vector mesons $ρ$ and $ω$ and the latter the hidden scalar meson, a dilaton $σ^$ (i.e., $f_{0} (500)$ ), play the crucial role. Going beyond the density regime applicable to normal nuclear matter $n_{0}$ , the notion of ``hadron-quark continuity HQC)" is brought in via the skyrmion structure of the nucleon argued to be valid in QCD at large $N_{c}$ limit and the large $N^{'}$ limit of the Grassmannian model $G / H = [O (N^{'}) / O (N^{'} - p) \times O (p)]$ where $N^{'} = 4$ and $p = 2$ for hidden local symmetry and the IR fixed point in QCD for $N_{f} \leq 3$ involving ``genuine/QCD-conformal dilaton" for hidden scale symmetry. The connection between the quenched $g_{A}$ and the sound speed $v_{s}^{2} / c^{2} \approx 1/3$ inside dense compact stars could be interpreted as a signal for emergent ``pseudo-conformal" symmetry.
Comments:
Rewritten as announced with title change
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2507.04939 [pdf]
J.Subatomic Part.Cosmol.(2025)·2 citations
07
[Submitted on 7 Jul 2025]
Extraction of ground-state nuclear deformations from ultra-relativistic heavy-ion collisions: Nuclear structure physics context
J. Dobaczewski🇬🇧 · A. Gade🇺🇸 · K. Godbey🇺🇸 · R.V.F. Janssens🇺🇸 · W. Nazarewicz🇺🇸
The collective-flow-assisted nuclear shape-imaging method in ultra-relativistic heavy-ion collisions has recently been used to characterize nuclear collective states. In this paper, we assess the foundations of the shape-imaging technique employed in these studies. We argue that some current UHIC nuclear imaging techniques neglect fundamental aspects of spontaneous symmetry-breaking and symmetry-restoration in colliding ions and incorrectly infer one-body multipole moments from studies of nucleonic correlations. Therefore, the impact of this approach on nuclear structure research has been overstated. Conversely, efforts to incorporate existing knowledge on nuclear shapes into analysis pipelines can be beneficial for benchmarking tools and calibrating models used to extract information from ultra-relativistic heavy-ion experiments.
Comments:
Version Accepted to Phys. Rev. Res
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2507.05208 [pdf]
PRResearch(2025)·20 citations
08
[Submitted on 18 Feb 2024] (cross-list from hep-ph)
The Properties of Radially Excited Charmonia in The Light Front Quark Model
Muhammad Ridwan🇮🇩 · Ahmad Jafar Arifi🇯🇵 · Terry Mart🇮🇩
Investigating the properties of excited charmonia is important to clarify its internal structure. In this paper, we present the mass spectra (MS) and decay constants (DC) for charmonia up to 3S states calculated by means of the light-front quark model based on a variational approach. In particular, we consider the QCD-motivated effective Hamiltonian, which includes both confinement (linear and screened) and Coulomb-like potentials. Furthermore, since the existence of the nature of heavy quark symmetry, we treat hyperfine interactions perturbatively. We developed the harmonic oscillator expansion method to approximate the wave function (WF) for excited states. We found that the results of our theoretical calculations, using screened potentials rather than linear ones, are in good agreement with experimental data. By looking at the mass and decay constant result, we found that our result on the {\psi}(3S) state matched the properties of the {\psi}(4040) resonance.
Comments:
ITM Web Conf. Volume 61, 2024, The 9th International Symposium on Current Progress in Mathematics and Sciences 2023 (The 9th ISCPMS 2023) in conjunction with AUA Academic Conference on the Application of Artificial Intelligences and Data Sciences in a Modern Science for a Better Life, 9 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2402.11564 [pdf]
ITM Web Conf.(2024)·4 citations
09
[Submitted on 20 Sept 2024] (cross-list from hep-ph)
Self-consistent $M 1$ radiative transitions of excited $B_{c}$ and heavy quarkonia with different polarizations in the light-front quark model
Muhammad Ridwan🇮🇩 · Ahmad Jafar Arifi🇯🇵 · Terry Mart🇮🇩
In this study, we investigate the properties of pseudoscalar and vector charmonia, bottomonia, and $B_{c}$ mesons using the light-front quark model, focusing on the $M 1$ radiative transition. For that purpose, we conduct a variational analysis with a QCD-motivated effective Hamiltonian, employing a trial wave function expanded in the harmonic oscillator basis functions up to the $3 S$ state. We fit the model parameters to mass spectra and decay constants, obtaining reasonable agreement with experimental data and correctly reflecting the hierarchy of mass spectra and decay constants. In analyzing the $M 1$ radiative transition, we consider both good ( $μ = +$ ) and transverse ( $μ = ⊥$ ) current components with both longitudinal $(h = 0)$ and transverse $(h = \pm 1)$ polarizations, demonstrating that the results from both components of currents and polarizations are identical. Self-consistency is achieved by substituting $M$ with $M_{0}$ when computing the operators for decay constants and radiative transitions. We also find that the difference between longitudinal and transverse polarizations of the observables may quantify the anisotropy of the model wave function. Our results on radiative transitions align reasonably well with experimental data, lattice QCD, and theoretical predictions. Furthermore, we also provide predictions for $B_{c}$ mesons that can be tested in experiments.
Comments:
24 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.13172 [pdf]
PRD(2025)·18 citations
10
[Submitted on 3 Jul 2025] (cross-list from hep-ph)
Soft background fields at next-to-leading power in transverse momentum dependent SIDIS with jets
Max Jaarsma🇳🇱 · Oscar del Rio🇪🇸 · Ignazio Scimemi🇪🇸 · Wouter Waalewijn🇳🇱
We present a factorization formula for the $e + h \to e + jet + X$ cross section at small transverse momenta up to next-to-leading power (NLP), derived using the background field method (BFM) with explicit inclusion of soft modes. We discuss the relation between soft modes and overlap subtractions at NLP, showing that the inclusion of soft modes enables a definition of twist-3 operators with properly subtracted rapidity and endpoint divergences. We also derive the effective current operator at NLP and identify additional structures compared to previous approaches based on soft-collinear effective theory and the BFM without soft modes. Nevertheless, for the hadronic tensor, we find agreement at the perturbative order that we are working at, and identify a condition that needs to be satisfied for this agreement to extend to higher orders. Furthermore, we construct the most general form factors for this process, taking into account the polarization of the initial states. These involve perturbatively-calculable jet functions, opening a path to precise determinations of twist-3 hadronic distributions. Finally, our formalism is illustrated with phenomenological results for a specific azimuthal asymmetry, whose leading-logarithmic contribution depends solely on a twist-3 hadronic distribution and a twist-2 jet function.
Comments:
68 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2507.03072 [pdf]
JHEP(2025)·8 citations
11
[Submitted on 3 Jul 2025] (cross-list from hep-ph)
Scattering off unstable states
Francesco Giacosa🇵🇱 · Vanamali Shastry🇺🇸
Unstable states that live long enough may appear as in(out)going particles in scattering experiments. Yet, the standard QFT approach strictly applies only to fully stable asymptotic states. This is evident when scattering involving unstable particles develops a $t$ -channel singularity at specific angles. We employ a finite-time formalism leading to analytic results without the singularity (even in the infinite-time limit), thus solving the problem at a phenomenological level. In turn, the approach also justifies treating long-lived particles, like weakly decaying pions, as stable during strong interactions.
Comments:
9 pages, 4 figures. To appear in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2507.03145 [pdf]
PRD(2026)·0 citations
12
[Submitted on 4 Jul 2025] (cross-list from astro-ph.HE)
Inferring the neutron star equation of state with nuclear-physics informed semiparametric models
Sunny Ng🇺🇸 · Isaac Legred🇺🇸 · Lami Suleiman🇺🇸 · Philippe Landry🇨🇦 · Lyla Traylor🇺🇸 · Jocelyn Read🇺🇸
Over the past decade, an abundance of information from neutron-star observations, nuclear experiments and theory has transformed our efforts to elucidate the properties of dense matter. However, at high densities relevant to the cores of neutron stars, substantial uncertainty about the dense matter equation of state (EoS) remains. In this work, we present a semiparametric EoS framework aimed at better integrating knowledge across these domains in astrophysical inference. We use a Meta-model at low densities, and Gaussian Process extensions at high densities. Comparisons between our semiparametric framework to fully nonparametric EoS representations show that imposing nuclear theoretical and experimental constraints through the Meta-model up to nuclear saturation density results in constraints on the pressure up to twice nuclear saturation density. We show that our Gaussian Process trained on EoS models with nucleonic, hyperonic, and quark compositions extends the range of EoS explored at high density compared to a piecewise polytropic extension schema, under the requirements of causality of matter and of supporting the existence of heavy pulsars. We find that maximum TOV masses above $3.2 M_{⊙}$ can be supported by causal EoS compatible with nuclear constraints at low densities. We then combine information from existing observations of heavy pulsar masses, gravitational waves from binary neutron star mergers, and X-ray pulse profile modeling of millisecond pulsars within a Bayesian inference scheme using our semiparametric EoS prior. With current astrophysical observations, we find a favored pressure at two times nuclear saturation density of $P (2 ρ_{nuc}) = 1.9 8_{- 1.08}^{+ 2.13} \times 1 0^{34}$ dyn/cm $^{2}$ , a radius of a $1.4 M_{⊙}$ neutron star value of $R_{1.4} = 11. 4_{- 0.60}^{+ 0.98}$ \;km, and $M_{max} = 2.3 1_{- 0.23}^{+ 0.35} M_{⊙}$ at the 90\% credible level.
Comments:
15 pages, 7 figures, matches the published version in Class. Quantum Grav (2025), added figure with sound speed constraints and table with relevant comparisons to other work. Associated Zenodo data release DOI: https://doi.org/10.5281/zenodo.15801144
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2507.03232 [pdf]
Class.Quant.Grav.(2025)·13 citations
13
[Submitted on 4 Jul 2025] (cross-list from hep-ph)
$M 1$ Radiative Transition of Light Mesons in the Light-Front Quark Model
Muhammad Ridwan🇮🇩 · Ahmad Jafar Arifi🇯🇵 · Terry Mart🇮🇩
We investigate the $M 1$ radiative transitions between light vector $V$ and pseudoscalar $P$ mesons in the 1S and 2S states in the light-front quark model. To this end, we use the light-front wave functions (LFWFs) obtained from the QCD-motivated effective Hamiltonian that includes smeared spin-spin interactions, where a few harmonic oscillator basis functions were employed as trial wave functions. The results, including their couplings and widths, obtained from LFWFs with different trial wave functions are compared with the available experimental data and other theoretical predictions.
Comments:
Contribution to the 14th International Physics Seminar (IPS) 2025; 7 pages, 2 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2507.03437 [pdf]
0 citations
14
[Submitted on 4 Jul 2025] (cross-list from physics.chem-ph)
Complex Absorbing Potential Green's Function Methods for Resonances
Loris Burth · Fábris Kossoski · Pierre-François Loos
The complex absorbing potential (CAP) formalism has been successfully employed in various wavefunction-based methods to study electronic resonance states. In contrast, Green's function-based methods are widely used to compute ionization potentials and electron affinities but have seen limited application to resonances. We integrate the CAP formalism within the $G W$ approximation, enabling the description of electronic resonances in a Green's function framework. This approach entails a fully complex treatment of orbitals and quasiparticle energies in a non-Hermitian setting. We validate our CAP- $G W$ implementation by applying it to the prototypical shape resonances of \ce{N2^-}, \ce{CO^-}, \ce{CO_2^-}, \ce{C2H2-}, \ce{C2H4-}, and \ce{CH2O-}. It offers a fast and practical route to approximate both the lifetimes and positions of resonance states, achieving an accuracy comparable to that of state-of-the-art wavefunction-based methods.
Comments:
18 pages, 7 figures
Subjects:
physics.chem-ph (physics.chem-ph); cond-mat.mtrl-sci (cond-mat.mtrl-sci); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
arXiv:
2507.03496 [pdf]
J.Chem.Theor.Comput.(2025)·0 citations
15
[Submitted on 4 Jul 2025] (cross-list from nucl-ex)
Search for the Efimov state near the 3 $α$ threshold
A. Baishya · S. Santra · T. Singh · P. C. Rout · A. Pal · H. Kumawat · T. Santhosh · P. Taya · M. Meher · Jyotisankar Das
A high-precision experiment in search of the predicted Efimov state in $^{12} C$ at 7.458 MeV excitation energy was performed. Using a state-of-the-art detector system and novel analysis techniques, it was possible to observe the Efimov state at the predicted energy level above the 3 $α$ threshold with much better sensitivity in the $^{12} C$ excitation energy spectrum compared to the existing data. The mutual $^{8} Be$ resonance (91.84 keV) condition filters out a total of 21 probable Efimov state events around 7.458 MeV. With 2 $σ$ confidence, it gives an upper limit of 0.014 $%$ for the Efimov state $α$ -decay width relative to that of the Hoyle state, which is about an order of magnitude smaller than the latest upper limit found in the literature. This observation was supported by a new penetrability calculation assuming a relatively extended structure of the Efimov state compared to the Hoyle state. The effect of the Efimov state was also explored in a nuclear astrophysical scenario, where the triple- $α$ reaction rate, including both the Hoyle state and the Efimov state, was found to be larger than the allowed limit, while the temperature dependence of the combined rate was found to be compatible with the helium shell flash criterion of the AGB stars.
Comments:
7 pages. 6 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2507.03514 [pdf]
PRC(2026)·1 citation
16
[Submitted on 4 Jul 2025] (cross-list from hep-ph)
Rotational susceptibility of a hot and dense hadronic matter
Bhagyarathi Sahoo🇮🇳 · Kshitish Kumar Pradhan🇮🇳 · Dushmanta Sahu🇲🇽 · Raghunath Sahoo🇮🇳
We study the effect of global rotation on rotational susceptibilities ( $χ_{ω}^{(1)}$ , $χ_{ω}^{2}$ , etc.), which quantify how much the system responds to small angular velocities, in a hadron resonance gas produced by ultra-relativistic heavy ion collisions. The higher-order rotational susceptibilities and their ratios are estimated in the presence and absence of baryon chemical potential ( $μ_{B}$ ) in the system. The effect of particle spin ( $s$ ) and system size ( $R$ ) on the first- and second-order rotational susceptibility is explored. To consider a more realistic scenario, the effect of interactions between hadrons is taken into account by considering van der Waals-like interactions, which include both attractive and repulsive interactions. To validate our results, a comparison with the ideal HRG as a baseline and a 3-flavour NJL model is shown. A nuclear liquid-gas phase transition, which is the characteristic feature of the van der Waals hadron resonance gas model, absent in an ideal hadron gas model, is probed via global rotation.
Comments:
Same as the published version in Eur. Phys. J A
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:
2507.03708 [pdf]
EPJA(2026)·2 citations
17
[Submitted on 6 Jul 2025] (cross-list from astro-ph.HE)
New Molecular Dynamics Methods for Simulating Neutron Star Crusts with Superfluid Vortices
M. E. Caplan🇺🇸 · N. T. Smith🇺🇸
Superfluid vortices in neutron star crusts are thought to be pinned to the lattice of nuclei in the crust. The unpinning of superfluid vortices in spin glitches therefore motivates us to study the vortex-crust interaction explicitly with molecular dynamics. In this work, we present a new molecular dynamics methods to characterize the response of the crust to a rigid vortex. When vortex pinning forces and nearest neighbor Coulomb forces are comparable, we observe a qualitatively new phenomena of lattice entrainment with implications for the elastic evolution of the crust.
Comments:
3 pages, 1 figure, published in RNAAS. Animation of Fig. 1 available in the "anc" folder (ancillary) files
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); cond-mat.other (cond-mat.other); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph)
arXiv:
2507.04527 [pdf]
Res.Notes AAS(2025)·1 citation
18
[Submitted on 7 Jul 2025] (cross-list from hep-ph)
Spin alignment of vector mesons in heavy-ion collision
Xin-Li Sheng🇮🇹 · Qun Wang🇨🇳
We give a brief review on the spin alignment induced by the strong field and the shear-stress tensor. In experiments, a significant positive deviation from 1/3 is observed for the $ϕ$ meson, which can be explained by the anisotropy of the strong field fluctuation in the meson's rest frame, while the anisotropy is mainly a consequence of the motion of meson relative to the quark-gluon plasma. On the other hand, the shear-induced spin alignment is of the order $1 0^{- 4} \sim 1 0^{- 5}$ if the magnitude of thermal shear tensor is $1 0^{- 2}$ .
Comments:
4 pages, 2 figures; proceedings of the The 10th Asian Triangle Heavy-Ion Conference (ATHIC 2025), Berhampur, Odisha, India, 13-16 Jan. 2025
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2507.04989 [pdf]
J.Subatomic Part.Cosmol.(2025)·0 citations
19
[Submitted on 7 Jul 2025] (cross-list from physics.atom-ph)
Laser spectroscopy and CP-violation sensitivity of actinium monofluoride
M. Athanasakis-Kaklamanakis🇨🇭 · M. Au🇨🇭 · A. Kyuberis🇳🇱 · C. Zülch🇩🇪 · K. Gaul🇩🇪 · H. Wibowo🇬🇧 · L. Skripnikov · L. Lalanne🇧🇪 · J. R. Reilly🇬🇧 · A. Koszorús🇨🇭 · S. Bara🇧🇪 · J. Ballof🇩🇪 and 30 other authors
The apparent invariance of the strong nuclear force under combined charge conjugation and parity (CP) remains an open question in modern physics. Precision experiments with heavy atoms and molecules can provide stringent constraints on CP violation via searches for effects due to permanent electric dipole moments and other CP-odd properties in leptons, hadrons, and nuclei. Radioactive molecules have been proposed as highly sensitive probes for such searches, but experiments with most such molecules have so far been beyond technical reach. Here we report the first production and spectroscopic study of a gas-phase actinium molecule, $^{227}$ AcF. We observe the predicted strongest electronic transition from the ground state, which is necessary for efficient readout in searches of symmetry-violating interactions. Furthermore, we perform electronic- and nuclear-structure calculations for $^{227}$ AcF to determine its sensitivity to various CP-violating parameters, and find that a realistic, near-term experiment with a precision of 1 mHz would improve current constraints on the CP-violating parameter hyperspace by three orders of magnitude. Our results thus highlight the potential of $^{227}$ AcF for exceptionally sensitive searches of CP violation.
Comments:
Submitted
Subjects:
Atomic Physics (physics.atom-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2507.05224 [pdf]
Nature(2025)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE