Nuclear Theory·nucl-th

Monday·August 18, 2025

6 papers—3 primary·3 cross-listed

01
[Submitted on 14 Aug 2025]
Nonflow suppression in flow analysis with a maximum likelihood estimator
Chong Ye🇨🇳 · Wei-Liang Qian🇨🇳 · Cesar A. Bernardes🇧🇷 · Sandra S. Padula🇧🇷 · Rui-Hong Yue🇨🇳 · Yutao Xing🇧🇷 · Takeshi Kodama🇧🇷
We show that the maximum likelihood estimator (MLE) is an effective tool for mitigating non-flow effects in flow analysis. To this end, one constructs two toy models that simulate non-flow contributions corresponding to particle decay and momentum conservation, respectively. The performance of MLE is analyzed by comparing it against standard approaches such as particle correlation and event plane methods. For both cases, MLE is observed to provide a reasonable estimate of the underlying flow harmonics, and in particular, its performance can be further improved when the specific form of the likelihood in the presence of non-flow can be assessed. The dependencies of extracted flow harmonics on the multiplicity of individual events and the total number of events are analyzed. Additionally, it is shown that the proposed approach performs efficiently in addressing deficiencies in detector acceptance. These findings suggest MLE as a compelling alternative to standard methods for flow analysis.
Comments:
18 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.11113 [pdf]
PRC(2026)·1 citation
02
[Submitted on 15 Aug 2025]
Low-lying level structures in $^{162}$ Lu
N Susshma · S Deepa · K Vijay Sai · R Gowrishankar
The well-tested empirical two quasiparticle rotor model calculations are used to characterize low-lying isomers in the odd-odd nucleus $^{162}$ Lu. Physically admissible 2qp bandheads are obtained to construct the low-energy level structure of the nucleus, assign spin-parity (J $^{π}$ ), orbital configuration, and level energies (E $_{x}$ ), for the gs and the two reported isomers. The spin-parity and orbital configuration of the 1.5 min isomer are confirmed to be J $^{π}$ = 4 $^{-}$ \{ $π$ 5/2 $^{+}$ [402 $↑$ ] $\otimes$ $ν$ 3/2 $^{-}$ [521 $↑$ ]\}. Its level energy has been estimated to be E $_{x}$ $\approx$ 62 keV. The 1.9 min isomer is characterized for the first time with J $^{π}$ = 6 $^{+}$ \{ $π$ 9/2 $^{-}$ [514 $↑$ ] $\otimes$ $ν$ 3/2 $^{-}$ [521 $↑$ ]\} and energy E $_{x}$ $\approx$ 157 keV. Based on these assignments, individual $β$ -decay branches of gs and the two isomers to the daughter levels in $^{162}$ Yb are proposed. The study is extended to neighboruing isotopes $^{164, 166, 168}$ Lu. A short-lived isomer, tentatively proposed in a previous study of $^{164}$ Lu, is identified as J $^{π}$ = 6 $^{+}$ \{ $π$ 7/2 $^{+}$ [404 $↓$ ] $\otimes$ $ν$ 5/2 $^{+}$ [402 $↑$ ]\} with energy E $_{x}$ $\approx$ 52 keV. The energy of the J $^{π}$ =3 $^{+}$ isomer in $^{168}$ Lu, currently listed with large uncertainty, is deduced as E $_{x}$ $\approx$ 100 keV significantly improving its value.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.11251 [pdf]
PRC(2026)·0 citations
03
[Submitted on 15 Aug 2025]
Highly efficient nuclear population transfer through physics-informed neural networks
Jing Liu · Fu-Quan Dou
Nuclear coherent population transfer (NCPT) offers numerous potential applications, particularly in next-generation nuclear clocks and nuclear batteries. However, the realization of high fidelity, fast operation, and low energy consumption in NCPT remains so far challenging. Here, we employ physics-informed neural networks (PINNs) to the population transfer in an open three-level nuclear system with spontaneous emission. The method embeds the system's control equations and boundary conditions into the loss function, thereby enabling the automatic learning of optimal laser pulse sequences that drive highly efficient population transfer. We take a short-lived excited state of $^{172} Yb$ and a long-lived state of $^{229} Th$ as representative examples, and systematically compare the performance of the PINNs approach with three conventional control strategies. We show that PINNs can achieve higher transfer efficiency with smaller pulse areas and shorter durations across different lifetime regimes. Our results provide a new perspective to overcome the lifetime limitation and enhance the efficiency of nuclear state transfer.
Comments:
8 pages,4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.11546 [pdf]
PRC(2026)·1 citation
04
[Submitted on 15 Aug 2025] (cross-list from hep-ph)
Studying the in-medium $ϕ$ meson spectrum through kaons in proton-nucleus reactions
Gabor Balassa🇰🇷 · Kazuya Aoki🇯🇵 · Philipp Gubler🇯🇵 · Su Houng Lee🇰🇷 · Hiroyuki Sako🇯🇵 · Gyorgy Wolf🇭🇺
Exploring the mass modifications of $ϕ$ mesons in nuclei provides insights into the nature of strongly interacting matter. Specifically, $ϕ$ meson mass shifts can be related to the in-medium modification of the strange quark condensate. Therefore, the partial restoration of chiral symmetry can be studied by observing the mass shifts through the decay channels $ϕ \to e^{+} e^{-}$ , and $ϕ \to K^{+} K^{-}$ . In this paper, we examine the possibility of observing the $ϕ$ meson mass modifications of the $ϕ$ mesons in 30 GeV proton-nucleus (C, Cu, Pb) collisions, to be studied at the J-PARC E88 experiment, through the kaonic decay channel, with the off-shell Budapest Boltzmann-Uehling-Uhlenbeck (BuBUU) transport model. By applying different mean fields to the kaons, we examine their effects on the invariant mass spectra. Our simulations suggest that, although different mean fields for the kaons do affect the spectrum, there is a common observable effect primarily driven by the $ϕ$ mass shift. However, due to the threshold associated with the two kaons, the signal we observe is quite different from the one expected in dilepton spectra. Therefore, to meaningfully constrain the mass shift, it will be useful to include both kaon and dilepton channels in the analysis of the experimental data.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.11344 [pdf]
PTEP(2025)·3 citations
05
[Submitted on 15 Aug 2025] (cross-list from hep-ph)
Exotic Heavy Hadrons
H- Garcilazo🇲🇽 · A. Valcarce🇪🇸
We review our recent findings on the structure and properties of exotic heavy hadrons, focusing on two main topics. First, we examine the role of correlations driven by the short-range Coulomb-like color interaction in hidden heavy-flavor pentaquarks. We show how this framework consistently accounts for the observed pattern of $P_{c}$ and $P_{cs}$ states in the hidden-charm sector and enables predictions for the hidden-bottom sector, where experimental data are still lacking. The second topic explores the possibility of forming stable multihadron molecules from deeply bound two-hadron exotic states. In this context, a bound state of three $B$ mesons, denoted as $T_{bbb}$ , with quantum numbers $(I) J^{P} = (1/2) 2^{-}$ , is presented. We find that the binding energy generally decreases as the number of hadrons increases, primarily due to effects of the Pauli principle and the appearance of new decay thresholds. Nonetheless, resonances may still arise in specific cases, depending on the internal thresholds of the system. Finally, we discuss how the decay width of an exotic multihadron resonance can offer valuable insights into its internal structure and underlying~dynamics.
Comments:
Invited review, 32 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.11483 [pdf]
Symmetry(2025)·4 citations
06
[Submitted on 15 Aug 2025] (cross-list from quant-ph)
Quantum Simulation of Collective Neutrino Oscillations in Dense Neutrino Environment
Shvetaank Tripathi🇮🇳 · Sandeep Joshi🇮🇳 · Garima Rajpoot🇮🇳 · Prashant Shukla🇮🇳
Inside dense neutrino gases, such as neutron star mergers or core-collapse supernovae, collective neutrino effects cause the transformation of one neutrino flavour into another. Due to strong neutrino self-interactions in these environments, there is prevalence of flavour swapping. Considering these environments to be isotropic and homogeneous, we present a study of collective neutrino oscillations by simulating such a system on a noisy quantum simulator (Qiskit AerSimulator) and a quantum processor (ibm\_brisbane). We model the effective Hamiltonian governing neutrino interactions and by applying the Trotter-Suzuki approximation, decompose it into a tractable form suitable for quantum circuit implementation of the time-evolution propagator. Encoding the neutrino state for a system of two- and three-neutrinos onto qubits, we compute the time evolution of the inversion probability relative to the initial product state. Furthermore, we present quantum circuits to evaluate the concurrence as a measure of entanglement between the neutrinos.
Comments:
23 pages, 10 figures
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.11610 [pdf]
Quant.Inf.Proc.(2026)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE

Nonflow suppression in flow analysis with a maximum likelihood estimator

Low-lying level structures in 162Lu

Highly efficient nuclear population transfer through physics-informed neural networks

Studying the in-medium ϕ meson spectrum through kaons in proton-nucleus reactions

Exotic Heavy Hadrons

Quantum Simulation of Collective Neutrino Oscillations in Dense Neutrino Environment

Affiliations

Low-lying level structures in $^{162}$ Lu

Studying the in-medium $ϕ$ meson spectrum through kaons in proton-nucleus reactions