arXiv subjects

Zhongbao Yin

Publications and source records attributed to Zhongbao Yin.

12 recordsLinked to original sources

arXiv2026

Opportunities for Imaging Light Nuclei with a Second Interaction Region at the Electron-Ion Collider

The upcoming Electron-Ion Collider (EIC) will address several outstanding puzzles in modern nuclear physics. Key questions-such as the partonic structure of nucleons and nuclei and the origin of their mass and spin-can be explored through high-energy electron-proton and electron-nucleus collisions. To maximize its scientific reach, the EIC community has advocated for the addition of a second interaction region equipped with a detector complementary to the EIC general purpose collider detector, ePIC. The pre-conceptual design of this interaction region aims to provide a different configuration from the first interaction region, which enhances forward acceptance at very small scattering angles ($θ\sim 0$ mrad). This machine configuration would significantly benefit exclusive, tagging, and diffractive physics programs, complementing those of the ePIC experiment. In particular, accessing coherent diffractive processes on light nuclei by tagging of the full, intact nucleus is essential for mapping their spatial parton distributions. In this work, we present an exploratory study of the detection capabilities for light nuclei at a second EIC interaction region, with a detailed discussion of the accessible kinematic phase space and its implications for imaging.

nucl-ex↗

arXiv2026

Studying Energy-Energy Correlators in pp Collisions at the LHC with a Jet-Free Event-Topology Method

We present a jet-free approach for measuring energy-energy correlators (EEC) in proton-proton (pp) collisions at the Large Hadron Collider (LHC), employing an event-topology method that does not rely on explicit jet reconstruction. Using the leading charged hadron as a reference axis, the azimuthal plane is divided into Toward and Transverse regions, enabling a robust background subtraction and extending EEC measurements into the low $p_T$ regime where conventional jet-based approaches become unreliable. The method is validated through comparisons with conventional jet reconstruction results. We systematically explore the dependence of the EEC on the leading-particle transverse momentum and parton flavor. The observed scaling between the EEC peak position and the hard scale suggests that this topology-based EEC captures effectively the transition between perturbative and non-perturbative QCD regimes. Distinct differences are found between quark- and gluon-initiated events, reflecting their different color charges and radiation patterns. Extending the analysis to heavy flavor, EECs triggered by leading charm mesons exhibit a suppressed magnitude and a peak shifted toward larger angular separations relative to inclusive charged-particle triggers, providing a direct manifestation of the dead-cone effect. This jet-free EEC framework offers a simple and experimentally robust tool for studying the scale and flavor dependence of the QCD dynamics, with promising applications to proton-nucleus and heavy-ion collisions at the LHC.

hep-ph↗

arXiv2025

Investigating jet induced identified hadron productions from the relative transverse activity classifier in pp collision at LHC

In this work, we systematically investigate the jet associated identified hadron productions of pions, kaons, and protons based on the event topological separation method in proton proton (pp) collisions at $\sqrt{s}=13$ TeV employing the AMPT model with PYTHIA8 initial conditions. Enabling relative transverse event activity classifier $R_T$, we analyze the transverse momentum ($p_T$) spectra and particle ratios in the jet aligned toward region and the underlying event (UE) contributions sensitive transverse region varying with $R_T$. The results indicate that the AMPT model, incorporating both partonic and hadronic final-state interactions, provides a satisfactory description to the experimental data of the $p_T$ differential yields, particle ratios and average transverse momentum of identified particles in both the toward and transverse regions across different event activity classes. By subtracting the UE contribution from the toward region using the transverse region hadron yield, we introduce the in-jet hadron productions to analyze the modifications to jet itself. We find that the in-jet baryon to meson ratios reveal a sensitive dependence on $R_T$ driven by final state interactions, leading to a unique crossing pattern at intermediate $p_T$. This behavior can be regarded as a novel signature for probing jet medium interactions and energy loss effects in small collision systems.

hep-ph↗

arXiv2025

Extracting the kinetic freeze-out properties of high energy pp collisions at the LHC with event shape classifiers

Event shape measurements are crucial for understanding the underlying event and multiple-parton interactions (MPIs) in high energy proton-proton (pp) collisions. In this paper, the Tsallis Blast-Wave model with independent non-extensive parameters for mesons and baryons, was applied to analyze transverse momentum spectra of charged pions, kaons, and protons in pp collision events at $\sqrt{s}=13$ TeV classified by event shape estimators relative transverse event activity, unweighted transverse spherocity, and flattenicity. Our analysis reveals consistent trends in the kinetic freeze-out temperature and non-extensive parameter across different collision systems and event shape classes. The use of diverse event-shape observables in pp collisions has significantly expanded the accessible freeze-out parameter space, allowing for a more comprehensive exploration of its boundaries. Among these event shape classifiers, flattenicity emerges as a unique observable for disentangling hard process contributions from additive MPI effects, allowing the isolation of collective motion effects encoded by the radial flow velocity. Through the analysis of the interplay between event-shape measurements and kinetic freeze-out properties, we gain deeper insights into the mechanisms responsible for flow-like signatures in pp collisions.

hep-ph↗

arXiv2022

Studying strange hadron productions via two-particle correlations in high energy proton-proton collisions

Strange hadron production in pp collisions at $\sqrt{s}= 7$ TeV is studied with PYTHIA 8 and EPOS event generators via the two-particle correlation method. After pairing charged particles as trigger particles with associated strange hadrons $(\mathrm{K}^{0}_{S}$ and $(Λ/\overlineΛ)$ , the strange baryon to meson per trigger yield ratios ${Y_{Δφ}^{\mathrm{h}-(Λ+\overlineΛ)}}$/$/{2Y_{Δφ}^{\mathrm{h}-\mathrm{K}^{0}_{S}}}$ dependent on transverse momentum ($p_{T})$ are investigated within the near- and away-side jet region as well as the underlying event (UE) region. The modified string fragmentation effects of color reconnection and string shoving mechanisms implemented in PYTHIA 8 and the final state evolution effects built in EPOS are compared in this study. It is found that $p_{T}$ dependence of the $Λ/\mathrm{K}^{0}_{S}$ per trigger yield ratio in UE is similar to that in the inclusive measurements while the in-jet result is smaller. We also show that the $Λ/\mathrm{K}^{0}_{S}$ ratio at both near- and away-side jet region in the intermediate $p_{T}$ region decreases significantly with trigger $p_{T}$, which suggests the hard process effects might contribute to the strange baryon to meson enhancement at intermediate $p_{T}$. The much higher $Λ/\mathrm{K}^{0}_{S}$ ratio in UE and the striking difference between the near and away side of the in-jet results with low trigger $p_{T}$ predicted by the EPOS model indicate that the soft process effects induced by the final state evolution further increase the strange baryon production and can be still effective in a higher $p_{T}$ region compared to the string fragmentation type models.

hep-ph↗

arXiv2022

BeAGLE: Benchmark $e$A Generator for LEptoproduction in high energy lepton-nucleus collisions

The upcoming Electron-Ion Collider (EIC) will address several outstanding puzzles in modern nuclear physics. Topics such as the partonic structure of nucleons and nuclei, the origin of their mass and spin, among others, can be understood via the study of high energy electron-proton ($ep$) and electron-nucleus ($e$A) collisions. Achieving the scientific goals of the EIC will require a novel electron-hadron collider and detectors capable to perform high-precision measurements, but also dedicated tools to model and interpret the data. To aid in the latter, we present a general-purpose $e$A Monte Carlo (MC) generator - BeAGLE. In this paper, we provide a general description of the models integrated into BeAGLE, applications of BeAGLE in $e$A physics, implications for detector requirements at the EIC, and the tuning of the parameters in BeAGLE based on available experimental data. Specifically, we focus on a selection of model and data comparisons in particle production in both $ep$ and $e$A collisions, where baseline particle distributions provide essential information to characterize the event. In addition, we investigate the collision geometry determination in $e$A collisions, which could be used as an experimental tool for varying the nuclear density.

physics.comp-ph↗

arXiv2022

Strange particle production in jets and underlying events in pp collisions at $\sqrt{s}~=~7$ TeV with PYTHIA8 generator

Strange hadron production in pp collisions at $\sqrt{s}~=~7$ TeV is studied in jets and underlying events using the PYTHIA8 event generator. Matching strange hadrons to the jet area and the underlying event area is expected to help us disentangle the strange particles produced in hard and soft processes. The yield and the relative production of strange hadrons dependent on the event multiplicity are investigated with the color reconnection and color rope mechanisms implemented in the PYTHIA8 framework. It is found that the inclusive strange hadron productions can be reasonably described by the color reconnection and color rope combined effects. A significant multiplicity dependent enhancement of the strange baryon production in the jet area is observed induced by the modified string fragmentation mechanisms, indicating the strange baryon enhancement persists in both the hard and the soft process. Multi-strange baryons are found to be more collimated with the jet axis than other strange hadrons in the string fragmentation picture with the jet shape analysis technique. Future experimental examination of these jet related strange hadron productions will provide more insight to the origin of strangeness enhancement in small systems.

hep-ph↗

arXiv2021

Investigation of the background in coherent $J/ψ$ production at the EIC

Understanding various fundamental properties of nucleons and nuclei are among the most important scientific goals at the upcoming Electron-Ion Collider (EIC). With the unprecedented opportunity provided by the next-generation machine, the EIC might provide definitive answers to many standing puzzles and open questions in modern nuclear physics. Here we investigate one of the golden measurements proposed at the EIC, which is to obtain the spatial gluon density distribution within a lead ($Pb$) nucleus. The proposed experimental process is the exclusive $J/ψ$ vector-meson production off the $Pb$ nucleus - $e+Pb\rightarrow e'+J/ψ+Pb'$. The Fourier transformation of the momentum transfer $|t|$ distribution of the coherent diffraction is the transverse gluon spatial distribution. In order to measure it, the experiment has to overcome an overwhelmingly large background arising from the incoherent diffractive production, where the nucleus $Pb'$ mostly breaks up into fragments of particles in the far-forward direction close to the hadron-going beam rapidity. In this paper, we systematically study the rejection of incoherent $J/ψ$ production by vetoing products from these nuclear breakups - protons, neutrons, and photons, which is based on the BeAGLE event generator and the most up-to-date EIC Far-forward Interaction Region design. The achieved vetoing efficiency, the ratio between the number of vetoed events and total incoherent events, ranges from about 80% - 99% depending on $|t|$, which can resolve at least the first minimum of the coherent diffractive distribution based on the Sar$\it{t}$re model. Experimental and accelerator machine challenges as well as potential improvements are discussed.

nucl-ex↗

arXiv2016

A systematic study of the initial state in heavy ion collisions based on the quark participant assumption

We investigate the initial state geometric quantities of heavy ion collisions based on the quark participant assumption in the Glauber multiple scattering approach. A systematic comparison to the nucleon participant assumption has been presented and confronted with the charged multiplicity measurements in various collision systems. It is found that the quark participant based assumption can be important to understand the data in multiplicity production and the initial spatial eccentricity in small systems.

nucl-th↗

arXiv2014

Cold nuclear matter effects on the color singlet J/psi production in d-Au collisions at RHIC

We use a Modified DKLMT model (called M-DKLMT model) to study the cold nuclear matter (CNM) effects on the color singlet J/psi production in dAu collisions at RHIC. The cold nuclear effect of dipole-nucleus interactions has been investigated by introducing a nuclear geometric effect function f(ξ) to study the nuclear geometry distribution effect in relativistic heavy-ion collisions. The dependencies of nuclear modification factors (RdA) on rapidity and centrality are studied and compared to experimental data. It is found that the M-DKLMT model can well describe the experimental results at both forward- and mid-rapidity regions in dAu collisions at RHIC.

hep-ph↗

arXiv2013

Strange and multi-strange particle production in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV with ALICE

We present ALICE results on strange and multi-strange hadron production as a function of centrality in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV at the LHC. Their transverse momentum spectra, yields and particle ratios are compared to the corresponding measurements in pp collisions to address strangeness enhancement and high $p_{\rm T}$ particle suppression. The results are also compared to measurements at RHIC and SPS energies.

nucl-ex↗

arXiv2012

Multi-strange baryon elliptic flow in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV measured with the ALICE detector

We present the results on elliptic flow with multi-strange baryons produced in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV. The analysis is performed with the ALICE detector at LHC. Multi-strange baryons are reconstructed via their decay topologies and the v_2 values are analyzed with the two-particle scalar product method. The p_T differential v_2 values are compared to the VISH2+1 model calculation and to the STAR measurements at 200 GeV in Au+Au collisions. We found that the model describes Ξand Ωv_2 measurements within experimental uncertainties. The differential flow of Ξand Ωis similar to the STAR measurements at 200 GeV in Au+Au collisions.

nucl-ex↗