arXiv subjects

Jinhui Chen

Publications and source records attributed to Jinhui Chen.

At least 37 records · Page 2Linked to original sources

arXiv2025

A Review on Intense Electromagnetic Fields in Heavy-Ion Collisions: Theoretical Predictions and Experimental Results

In heavy-ion collisions at relativistic energies, the incident nuclei travel at nearly the speed of light. These collisions deposit kinetic energy into the overlap region and create a high-temperature environment where hadrons ``melt'' into deconfined quarks and gluons. The spectator nucleons, which do not undergo scatterings, generate an ultra-intense electromagnetic field -- on the order of $10^{18}$ Gauss at Relativistic Heavy-Ion Collider, and $10^{19}$ Gauss at the Large Hadron Collider. These powerful electromagnetic fields have a significant impact on the produced particles, not only complicating the study of particle interactions but also inducing novel physical phenomena. To explore the nature of these fields and their interactions with deconfined quarks, we provide a detailed overview, encompassing theoretical estimations of their generation and evolution, as well as experimental efforts to detect them. We also provide physical interpretations of the discovered results and discuss potential directions for future investigations.

nucl-ex↗

arXiv2025

New constraints on equation of state of hot QCD matter

The longitudinal structure of the quark-gluon plasma(QGP) remains a key challenge in heavy-ion physics. In this Letter, we propose a novel observable, event-by-event mean transverse momentum fluctuations Var$_{\langle p_{T} \rangle}$, which is sensitive to the local pressure gradients and serves as a probe of longitudinal dynamics in the initial state of QGP. We demonstrate that the covariance of averaged transverse momentum at two rapidities $\mathrm{Cov}_{\langle p_T \rangle}(η_1, η_2)$ and its associated decorrelation measures, $R_{p_T}(η_1, η_2)$ and $r_{p_T}(η, η_{\mathrm{ref}})$, exhibit strong sensitivity to the stiffness of equation of state (EoS) of QGP, while showing negligible dependence on the QGP transport coefficients. This distinctive behavior, revealed through state-of-the-art (3+1)-dimensional hydrodynamic simulations, establishes a powerful approach for constraining the EoS of QCD matter. In the meantime, our results provide new insights into the longitudinal structure of the QGP and its properties under high baryon density.

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arXiv2025

Method to search for the triple-neutron state in an electron scattering experiment

An electron scattering experiment to search for the trineutron state $^3n$ by reaction ${\rm ^4He}(e,~e'pπ^{+})^{3}n$ is designed for the A1 facility at Mainzer Microtron. The detailed principles, setup, and simulation of this experiment are presented. With the momenta of the scattered electron, the produced proton and $π^+$ from the reaction measured by three spectrometers with their triple coincidence, the missing mass spectrum of $^3n$ can be obtained. The production rate of $^3n$ based on the cross section of the reaction and a MC simulation is estimated to be about 1.5 per day, which can provide a confidence level of the signal greater than 5$σ$ with a beam time longer than 16 days. According to a MC simulation that evaluates the energy losses of particles in materials and the performance of three spectrometers, the estimated resolution and the predicted shape of the missing mass spectrum are presented. This work provides a new experimental concept for the search for multineutron states in future experiments with an electron beam.

physics.ins-det↗

arXiv2025

Comment on "Exploring Data-Driven Corrections for $ϕ$-Meson Global Spin Alignment Measurements" (arXiv:2508.18409)

The method in arXiv:2508.18409 constructs a ``data-driven correction'' from combinatorial (pseudo-$ϕ$) pairs and applies it to the signal. An explicit decomposition shows that the construction calibrates the background response rather than the signal: it is defined by the difference between an acceptance-free pseudo-$ϕ$ surrogate and its data-level realization. Promoting a background-derived correction to a signal correction requires a strong physics proof that signal and background share identical detector response at the pair level -- including acceptance-anisotropy couplings and dependencies on parent kinematics -- which the manuscript does not establish. Consequently, local numerical proximity in a restricted region of phase space is incidental rather than evidentiary; validation must rest on mechanism, not numerical coincidence. Moreover, the pseudo-$ϕ$ background is non-unique: with infinitely many admissible constructions, any apparent agreement for a few cases would not be dispositive -- no finite scan can substitute for a mechanism-level response equivalence. In the absence of such a demonstrated equivalence, the construction should be regarded as a background calibration rather than a signal correction.

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arXiv2025

Measurement of $\rm ^{6}H$ ground state energy in an electron scattering experiment at MAMI-A1

For the first time the neutron-rich hydrogen isotope $\rm ^{6}H$ was produced in an electron scattering experiment in the reaction $\rm ^{7}Li(e,~e'pπ^{+})^{6}H$ using the spectrometer facility of the A1 Collaboration at the Mainz Microtron accelerator. By measuring the triple coincidence between the scattered electron, the produced proton, and $π^{+}$, the missing mass spectrum of $\rm ^{6}H$ was obtained. A clear peak above $^3$H+n+n+n energy threshold was seen resulting in a ground state energy of $\rm ^{6}H$ at $2.3\pm0.5({\rm stat.})\pm0.4({\rm syst.})$ MeV with a width of $1.9\pm1.0({\rm stat.})\pm0.4({\rm syst.})$ MeV. This work challenges the understandings of multi-nucleon interactions and presents a new method to study light neutron-rich nuclei with electron scattering experiments.

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arXiv2025

Foveated Instance Segmentation

Instance segmentation is essential for augmented reality and virtual reality (AR/VR) as it enables precise object recognition and interaction, enhancing the integration of virtual and real-world elements for an immersive experience. However, the high computational overhead of segmentation limits its application on resource-constrained AR/VR devices, causing large processing latency and degrading user experience. In contrast to conventional scenarios, AR/VR users typically focus on only a few regions within their field of view before shifting perspective, allowing segmentation to be concentrated on gaze-specific areas. This insight drives the need for efficient segmentation methods that prioritize processing instance of interest, reducing computational load and enhancing real-time performance. In this paper, we present a foveated instance segmentation (FovealSeg) framework that leverages real-time user gaze data to perform instance segmentation exclusively on instance of interest, resulting in substantial computational savings. Evaluation results show that FSNet achieves an IoU of 0.56 on ADE20K and 0.54 on LVIS, notably outperforming the baseline. The code is available at https://github.com/SAI-

cs.CV↗

arXiv2025

Validation and extrapolation of atomic mass with physics-informed fully connected neural network

Machine learning offers a powerful framework for validating and predicting atomic mass. We compare three improved neural network methods for representation and extrapolation for atomic mass prediction. The powerful method, adopting a macroscopic-microscopic approach and treating complex nuclear effects as output labels, achieves superior accuracy in AME2020, yielding a much lower root-mean-square deviation of 0.122 MeV in the test set, significantly lower than alternative methods. It also exhibits a better extrapolation performance when predicting AME2020 from AME2016, with a root-mean-square deviation of 0.191 MeV. We further conduct sensitivity analyses against the model inputs to verify interpretable alignment beyond statistical metrics. Incorporating theoretical predictions of magic numbers and masses, our fully connected neural networks reproduce key nuclear phenomena including nucleon pairing correlation and magic number effects. The extrapolation capability of the framework is discussed and the accuracy of predicting new mass measurements for isotope chains has also been tested.

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arXiv2025

Scintillation and Timing Performance of a 3at% Yttrium-Doped Barium Fluoride Crystal

We report the scintillation and timing performance of a new developed 200 * 20 mm * 20 mm large size barium fluoride crystal doped with 3at% yttrium (BaF2:Y) to enhance the application for high time resolution. This doping effectively suppresses the slow scintillation component while maintaining most of the fast component, as confirmed by X-ray excited luminescence measurements. The BaF2:Y crystal demonstrated a transmittance of near 90% in the visible spectrum and a light response uniformity parameter of delta = (-2.74 +- 1.15)% when coupled with the tail end. The actual yttrium content varied from 2.1at% near the seed end to 3.7at% at the tail end. The assembled large BaF2:Y detector with silicon photomultipliers exhibited a time resolution of (82.2 +- 2.6) ps using constant fraction discrimination method in a cosmic ray test and (140.1 +- 3.8) ps using a low fixed threshold method in a beam test at Shanghai Synchrotron Radiation Facility with an 1.35 GeV electron beam. These results indicate the significant potential of BaF2:Y crystal for various applications, such as detectors for particle physics and nuclear physics.

physics.ins-det↗

arXiv2025

$Ab$-$initio$ nucleon-nucleon correlations and their impact on high energy $^{16}$O+$^{16}$O collisions

Investigating nucleon-nucleon correlations inherent to the strong nuclear force is one of the core goals in nuclear physics research. We showcase the unique opportunities offered by collisions of $^{16}$O nuclei at high-energy facilities to reveal detailed many-body properties of the nuclear ground state. We interface existing knowledge about the geometry of $^{16}$O coming from \textit{ab-initio} calculations of nuclear structure with transport simulations of high-energy $^{16}$O+$^{16}$O collisions. Bulk observables in these processes, such as the elliptic flow or the fluctuations of the mean transverse momentum, are found to depend significantly on the input nuclear model and to be sensitive to realistic clustering and short-range repulsive correlations, effectively opening a new avenue to probe these features experimentally. This finding demonstrates collisions of oxygen nuclei as a tool to elucidate initial conditions of small collision systems while fostering connections with effective field theories of nuclei rooted in quantum chromodynamics (QCD).

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arXiv2025

Energy dependence of transverse momentum fluctuations in Au+Au collisions from a multiphase transport model

Event-by-event mean transverse momentum fluctuations ($\langle p_\mathrm{T}\rangle$) serve as a sensitive probe of initial state overlap geometry and energy density fluctuations in relativistic heavy-ion collisions. We present a systematic investigation of $\langle p_\mathrm{T}\rangle$ fluctuations in \auau collisions at $\mathrm{\sqrt{s_{NN}}} =$3.0-19.6 GeV, examining their centrality and energy dependence with the framework of an improved multiphase transport (AMPT) model. The centrality dependence of the $p_\mathrm{T}$ cumulants up to fourth order deviates significantly from simple powering-law scaling. Scaled cumulants are performed, with variances aligning well with the trends observed in the experimental data. Employing a two-subevent method, short-range correlations are slightly suppressed compared to the standard approach. Furthermore, baryons exhibit more pronounced $\langle p_\mathrm{T}\rangle$ fluctuations than mesons, potentially attributable to the effect of radial flow. These results provide referenced insights into the role of initial state fluctuations across different energies in heavy-ion collisions.

nucl-th↗

arXiv2024

Production of exotic hadrons in $pp$ and nuclear collisions

Exotic hadrons beyond the conventional quark model have been discovered in the past two decades. Investigations of these states can lead to deep understanding of nonperturbative dynamics of the strong interaction. In this concise review, we focus on the productions of exotic hadrons in $pp$, $p\bar p$, and nuclear collisions. Experimental observations of light nuclei and hypernuclei, as prototypes of hadronic molecules, in heavy ion collisions will also be briefly discussed.

hep-ph↗

arXiv2024

Effect of vector meson spin coherence on the measurements of chiral magnetic effect in heavy-ion collisions

The chiral magnetic effect (CME) in heavy-ion collisions reflects the local violation of ${\cal P}$ and ${\cal CP}$ symmetries in strong interactions and manifests as electric charge separation along the direction of the magnetic field created by the wounded nuclei. The experimental observables for the CME, such as the $γ_{112}$ correlator, the $R_{Ψ_2}(ΔS)$ correlator, and the signed balance functions, however, are also subject to non-CME backgrounds, including those from resonance decays. A previous study showed that the CME observables are affected by the diagonal component of the spin density matrix, the $ρ_{00}$ for vector mesons. In this work, we study the contributions from the other elements of the spin density matrix using a toy model and a multiphase transport model. We find that the real part of the $ρ_{1-1}$ component, $\mathrm{Re}\,ρ_{1-1}$, affects the CME observables in a manner opposite to that of the $ρ_{00}$. All three aforementioned CME observables show a linear dependence on $\mathrm{Re}\,ρ_{1-1}$ in the model calculations, supporting our analytical derivations. The rest elements of the spin density matrix do not contribute to the CME observables. The off-diagonal terms in the spin density matrix indicate spin coherence and may be nonzero in heavy-ion collisions due to local spin polarization or spin-spin correlations. Thus, $\mathrm{Re}\,ρ_{1-1}$, along with $ρ_{00}$, could play a significant role in interpreting measurements in search of the CME.

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arXiv2024

Systematic investigation of the nuclear multiple deformations in U+U collisions with A Multi-Phase Transport model

Relativistic heavy ion collisions provide a unique opportunity to study the shape of colliding nuclei, even up to higher-order multiple deformations. In this work, several observables that are sensitive to quadrupole and hexadecapole deformations of Uranium-238 in relativistic U+U collisions have been systematically investigated with A Multi-Phase Transport model. We find that the flow harmonic $v_{2}$, the $v_{2}$ and mean transverse momentum correlation, and the three-particle asymmetry cumulant ${\rm ac}_{2}\{3\}$ are sensitive to nuclear quadrupole deformation, while ${\rm ac}_{2}\{3\}$ and nonlinear response coefficient $χ_{4,22}$ are sensitive to nuclear hexadecapole deformation. Our results from transport model studies are in qualitative agreement with previous hydrodynamic studies. The results indicate that the uncertainties of the hexadecapole deformation of Uranium on the quadrupole deformation determination can be reduced by the abundance of correlation observables provided by the relativistic heavy ion collisions.

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arXiv2024

Considerations on measuring spin-spin correlation of hyeprons in heavy-ion experiments

The significant global spin alignment observed for $ϕ$ mesons in heavy-ion collisions has sparked intense discussions about its origin and implications. One explanation suggests that fluctuations in the strong force field may introduce strong spin correlations between strange ($s$) and anti-strange ($\bar{s}$) quarks, leading to the global spin alignment of $ϕ$ mesons. Extending this line of research, the theoretical community has proposed studying the spin correlation between $Λ$ and $\barΛ$ hyperons. In this paper, we construct experimental observables and make connections between them and the theoretical proposed quantities.

nucl-th↗

arXiv2024

Properties of the QCD Matter -- An Experimental Review of Selected Results from RHIC BES Program

In the paper, we discuss the development of the multi-gap resistive plate chamber Time-of-Flight (TOF) technology and the production of the STAR TOF detector in China at the beginning of the 21st century. Then we review recent experimental results from the first beam energy scan program (BES-I) at the Relativistic Heavy Ion Collider (RHIC). Topics cover measurements of collectivity, chirality, criticality, global polarization, strangeness, heavy-flavor, di-lepton and light nuclei productions.

nucl-ex↗

arXiv2024

Electromagnetic fields in ultra-peripheral relativistic heavy-ion collisions

Ultraperipheral heavy-ion collisions (UPCs) offer unique opportunities to study processes under strong electromagnetic fields. In these collisions, highly charged fast-moving ions carry strong electromagnetic fields that can be effectively treated as photon fluxes. The exchange of photons can induce photonuclear and two-photon interactions, and excite ions. This excitation of the ions results in Coulomb dissociation with the emission of photons, neutrons, and other particles. Additionally, the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ions. Consequently, the two colliding ions experienced an electromagnetic force that pushed them in opposite directions, causing a back-to-back correlation in the emitted neutrons. Using a Monte Carlo simulation, we qualitatively demonstrated that the above electromagnetic effect is large enough to be observed in UPCs, which would provide a clear means to study strong electromagnetic fields and their effects.

nucl-th↗

arXiv2024

On the role of $J/ψ$ production in electron-ion collisions

Within the framework of non-relativistic QCD (NRQCD) effective field theory, we study the leptoproduction of $J/ψ$ at next-to-leading order in perturbative QCD for both unpolarized and polarized electron-ion collisions. We demonstrate that the $J/ψ$-tagged deep inelastic scattering in the future Electron-Ion Collider can be served as a golden channel for the reasons including constraining NRQCD long distance matrix elements, probing the nuclear gluon distribution functions, as well as investigating the gluon helicity distribution inside a longitudinal polarized proton.

hep-ph↗

arXiv2023

Measurements of the lightest hypernucleus ($\mathrm{^3_ΛH}$): progress and perspective

The hyperon-nucleon ($Y$-$N$) interaction is important for the description of the equation-of-state of high baryon density matter. Hypernuclei, the cluster object of nucleons and hyperons, serve as cornerstones of a full understanding of the $Y$-$N$ interaction. Recent measurements of the lightest known hypernucleus, the hypertriton's ($\mathrm{^3_ΛH}$) and anti-hypertriton's ($\mathrm{^3_{\barΛ}\bar{H}}$) lifetime, mass and $Λ$ separation energy have attracted interests on the subject. Its cross section and collective flow parameters have also been measured in heavy-ion collisions, which have revealed new features on its production mechanism. In this article we summarise recent measurements of $\mathrm{^3_ΛH}$, focusing on the heavy-ion collisions. We will discuss their implications for the $\mathrm{^3_ΛH}$ properties and the constrains on the $Y$-$N$ interaction models.

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