The 2026 International Workshop on the High Energy Circular Electron Positron Collider

Oct 21, 2026, 9:00 AM → Oct 26, 2026, 6:15 PM Asia/Shanghai

Sheraton Shanghai Jiading Hotel

Xiaolong Wang (Fudan University), Junfeng Chen (Shanghai Institute of Ceramics, Chinese Academy of Sciences（中国科学院上海硅酸盐研究所）), Jianchun Wang (IHEP), Miao He (IHEP), Jiayin Gu (Fudan University)

The 2026 International Workshop on the High-Energy Circular Electron-Positron Collider (CEPC2026) will be held in Shanghai from October 22 to 26, 2026. The event is jointly hosted by Fudan University (FDU), the Shanghai Institute of Ceramics (SIC/CAS), and the Institute of High Energy Physics (IHEP/CAS). This annual workshop brings together scientists from around the world to explore the physics potential of future high-energy circular electron-positron colliders . It fosters international collaboration to optimize accelerator and detector designs, and advances R&D on critical technologies.

The workshop will feature plenary, parallel, and poster sessions. All plenary presentations will be invited talks, while poster presentations will be selected from submitted abstracts. The oral presentations in the parallel sessions will be drawn from both invited speakers and submitted abstracts. We especially encourage participation from graduate students and postdocs. Outstanding posters will be recognized with awards, chosen by a selection committee composed of Scientific Program Committee (SPC) members, session conveners, and local organizers.

The program will also showcase exhibitions by leading industrial partners, offering attendees a firsthand look at cutting-edge innovations and advanced prototypes, along with focused discussions on technology research and development, and strategies for industrialization readiness.

Deadline for abstract submission is September 6, 2026. Deadline for registration is September 30, 2026. For information about visa applications, please visit the dedicated page at https://indico.ihep.ac.cn/event/cepc2026/, which is also accessible via the registration page. 

For assistance, please contact our support email address cepcws2026@ihep.ac.cn. All payments will be processed on-site, and any official notices will be sent exclusively from this address.  

CEPC2026 WeChat Group QR Code

Wednesday, October 21

2:00 PM Registration

Thursday, October 22

Welcome

Convener: XiaoLong Wang (Fudan University)

1 Welcome Opening

Plenary: 1

Thursday Morning: Grand Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

Monday Afternoon: Junior Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

2 Exploring the Electroweak scale with precision

Speaker: Patrick Meade (Stony Brook University)

3 Strategy of the CEPC

Speaker: Xinchou LOU (高能所)

4 Discussion

10:10 AM Coffee break

Plenary: 2

Thursday Morning: Grand Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

Monday Afternoon: Junior Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

5 Status of FCC-ee

6 CEPC accelerator - technologies & potential contribution to FCC-ee

Speaker: Jie GAO (IHEP)

7 Status and plan of the AGORA detector

Speaker: Joao Guimaraes da Costa

8 Progress towards implementation of Agentic AI

Speaker: Mihoko Nojiri (KEK)

12:40 PM Lunch break

Accelerator: 1

Zoom Link, ID: 94805716496, Code: 217749

CIPC & Industrial Partnerships: 1

Zoom Link, ID: 934 7906 6977, Code: 522727

Higgs Physics: 1

Zoom Link, ID:99229612134, Code: 887914

Silicon Detectors: 1

Zoom Link, ID: 91011235165, Code: 983836

3:30 PM Coffee break

Accelerator: 2

Zoom Link, ID: 94805716496, Code: 217749

CIPC & Industrial Partnerships: 2

Zoom Link, ID: 934 7906 6977, Code: 522727

Higgs Physics: 2

Zoom Link, ID:99229612134, Code: 887914

Silicon Detectors: 2

Zoom Link, ID: 91011235165, Code: 983836

7:00 PM Reception

Friday, October 23

Accelerator: 3

Zoom Link, ID: 94805716496, Code: 217749

CIPC & Industrial Partnerships: 3

Zoom Link, ID: 934 7906 6977, Code: 522727

Higgs Physics: 3

Zoom Link, ID:99229612134, Code: 887914

Silicon Detectors: 3

Zoom Link, ID: 91011235165, Code: 983836

10:30 AM Coffee break

Accelerator: 4

Zoom Link, ID: 94805716496, Code: 217749

Calorimetry: 1

Zoom Link, ID: 91011235165, Code: 983836

Physics Beyond SM: 1

Friday Morning: Function Room 11
Zoom Link, ID: 934 7906 6977, Code: 522727

Friday Afternoon and Saturday Morning: Junior Ballroom I
Zoom Link, ID:99229612134, Code: 887914

9 Probing the Electroweak Phase Transition with Long-Lived Scalars at Future Lepton Colliders

A strong first-order electroweak phase transition (EWPT) can be realized through the introduction of a light scalar that is weakly coupled to the Higgs boson. Such weak couplings can result in a macroscopic lifetime, leading to displaced decays that provide a distinctive experimental signature. In this talk, we investigate the sensitivity of future lepton colliders to long-lived scalars "s" produced in Higgs decays through e^+e^- -> ZH, with H -> ss and the scalars decaying at displaced vertices. Using realistic detector simulation, we develop a selection-based analysis and explore machine learning methods using detector level information to further improve the sensitivity. Our results demonstrate the potential of long-lived particle searches at future lepton colliders to provide a new probe of EWPT physics.

Speaker: Xiang Chen (Shanghai Jiao Tong University)

10 Probing Dark Matter in the Low-Mass 2HDM+a Framework at √s = 240 GeV Lepton Factories

The two-Higgs-doublet model with a light pseudoscalar singlet (2HDM + a) provides a wellmotivated dark matter (DM) framework, but hadron colliders face severe background ceilings
in the light-scalar (mh1) and light-mediator (ma) windows, while non-relativistic directdetection bounds are momentum-suppressed. To address these experimental bottlenecks, this study investigates the potential of future circular e+e− Higgs factories—specifically the CEPC and FCC-ee operating at √s = 240 GeV—to chart this elusive parameter space using the model-independent recoil mass method. Automating Monte Carlo simulation, we map the multi-body signal e+e− → Zh1 → µ+µ− + 4χ over a comprehensive two-dimensional grid spanning mh1 =125 GeV and ma ∈ [20, 80] GeV. Discrete DM mass targets (mχ = 5, 10 GeV) demonstrate threshold-driven phase-space enhancements immediately above ma > 2mχ. We show that future lepton colliders can achieve definitive discovery metrics well above the 5σ threshold that remain highly resilient under a conservative 10% background systematic scaling.

Speaker: Prof. Yuri Kulchitsky (JINR / IP NASB)

11 Scalar Portals to Dark Matter

The search for dark matter at accelerators has a long history, dating back to the first proposals for the LHC and even earlier. While complementary to direct detection in certain respects, accelerator-based searches offer distinct advantages, particularly when investigating a complex dark sector and multi-step processes. As a precision machine with unique potential, the planned CEPC accelerator is capable of covering regions of the parameter space of new physics models that remained beyond the sensitivity reach of the LHC. In the talk we discuss a range of scalar portal models that are of interest for study at the CEPC, taking into account existing constraints from the LHC.

Speaker: Maria Savina (JINR)

12 Probe Axion-Like Particles and Tau Weak Electric Dipole Moments at Future Lepton Colliders

Speaker: Keping (可平) Xie (谢) (Tsung-Dao Lee Institute, Shanghai Jiao Tong University)

QCD: 1

Zoom Link, ID:99229612134, Code: 887914

13 Stable NNLO QCD Predictions for Quarkonium Production and Decay

Heavy quarkonia provide ideal probes of strong interactions in both the perturbative and nonperturbative regimes. They have therefore been extensively studied at a wide range of accelerator-based high-energy experiments, including electron-positron colliders such as BESIII, Belle, and LEP, as well as at future facilities. However, NNLO QCD predictions for quarkonium production and decay processes are known to suffer from perturbative instabilities. We identify the origin of this instability and propose a remedy that significantly improves the perturbative stability of the NNLO predictions and the agreement between theory and data.

Reference: https://arxiv.org/abs/2606.28494

Speaker: Guoxing Wang (LPTHE, CNRS, France)

14 The Four-Jet Production in Electron-Positron Annihilation at Order alpha_s^4

In this talk, I will present the calculation of next-to-next-to-leading-order (NNLO) correction to four-jet production in electron–positron annihilation. We for the first time predicated present precise phenomenological predictions for the four-jet rate. I will then present NNLO predictions for several four-jet event-shape distributions and investigate the corresponding hadronisation effects.

Speaker: Huiting Sun (山东大学物理学院)

15 Complete angular analysis of polarized top-quark decay at NNLO in QCD with a finite bottom-quark mass

We present the next-to-next-to-leading-order (NNLO) QCD corrections to the
angular distribution of the polarized top-quark decay
$t(\uparrow)\to W^+X_b$, followed by $W^+\to\ell^+\nu_\ell$, with an on-shell
$W$ boson. We compute eight helicity structure functions, comprising
three spin-independent and five spin-dependent functions, through
$\mathcal{O}(\alpha_s^2)$, both in the massless-bottom approximation and with
the bottom-quark mass retained. These results extend the complete
next-to-leading-order angular analysis to NNLO and provide consistent
predictions for the total decay width, the $W$-boson helicity fractions,
polar-angle asymmetries, azimuthal correlations, and the elements of the
top--$W$ double density matrix.

Speaker: 国富 徐 (山东大学物理学院)

16 Measurement of $\Xi^{-} / \bar{\Xi}^{+}$ production in jets from Z boson decays with the DELPHI open data

This presentation reports the studies of the $\Xi^{-} / \bar{\Xi}^{+}$ baryon production in energy-ranked jets produced in $Z\to\text{hadrons}$ decays using the DELPHI open data. Jets are reconstructed using the Durham algorithm with $y_{\text{cut}}=0.005$. Quark- and gluon-enriched jet samples are obtained by ranking the jet energies in three-jet events. The softest jets are found to produce fewer $\Xi^{-}/\bar{\Xi}^{+}$ and less energetic baryons than the other jets. The ratio of $\Xi^{-}/\bar{\Xi}^{+}$ production rates in gluon and quark jets, each normalized to the corresponding mean charged-particle multiplicity, is measured. The result is consistent with the JETSET expectation and the OPAL measurements of $K_S^0$ and $\Lambda$ productions in $Z$ decays. Preliminary investigation of $\Lambda\bar\Lambda$ pair production is also presented. These studies provide new insights into strange-quark production and hadronization. Future $e^{+}e^{-}$ colliders such as CEPC and FCCee will provide much larger $Z$-boson samples and will allow far more precise studies of the subject.

Speaker: Dr Yuzhi Che (IHEP)

12:30 PM Lunch break

Accelerator: 5

Zoom Link, ID: 94805716496, Code: 217749

Calorimetry: 2

Zoom Link, ID: 91011235165, Code: 983836

QCD: 2

Zoom Link, ID:99229612134, Code: 887914

17 Tracing QCD Vacuum Fluctuations during Hadronization with Conserved Currents

We propose the first moments of electric-charge, baryon-number, and strangeness flows into jets as direct probes of the flavor composition and diquark content of the QCD vacuum excitations during hadronization. Current conservation laws render these moments invariant under renormalization-group evolution, while color triality constrains the allowed screening states at the endpoint of the associated Wilson line. In a minimal screening picture, the baryon-number flow in a quark jet of flavor $f$ obeys $\langle B_{\rm flow}\rangle_f \simeq r_{qq}/(1+r_{qq})$, where $r_{qq}$ is the relative production weight of diquark--antidiquark and quark--antiquark vacuum excitations. If the pair-production weights among different flavors satisfy $u\bar u:d\bar d:s\bar s=1:1:r_s$, the strangeness flow obeys $\langle S_{\rm flow}\rangle_f \simeq S_f+\frac{3r_s}{2+r_s}\left(\frac{1}{3}-\langle B_{\rm flow}\rangle_f\right)$, predicting a nonzero net strangeness even in $u$- and $d$-initiated jets. The charge flow obeys an analogous relation, and isospin-symmetric pair production makes the three flows satisfy the Gell-Mann--Nishijima relation $\langle Q_{\rm flow}\rangle_f \simeq I_{3,f} +\frac{1}{2}\left(\langle B_{\rm flow}\rangle_f+\langle S_{\rm flow}\rangle_f\right)$, providing an internal consistency condition among the three observables. Event-generator studies reproduce these relations and demonstrate that joint measurements of $Q$, $B$, and $S$ can separately constrain $r_{qq}$ and $r_s$, providing a flavor-resolved probe of vacuum pair production and quantum-number transport during jet hadronization.

Speaker: Wanchen Li (Fudan University)

18 Resolving the Light-Flavor Composition of Hadronic Z Decays with DELPHI Open Data

We report a direct determination of the strange-quark fraction in hadronic Z decays using DELPHI open data. A five-flavor ParticleNet representation defines exclusive flavor-enriched and remainder counts, while an independent data/simulation sample constrains the flavor response and its associated uncertainties. A simultaneous fit with freely floating bottom and charm fractions separates the strange contribution from the complementary (u+d) component without imposing (Rd = Rs), allowing the light-flavor composition to be determined directly from the flavor-tagged event yields. The heavy-flavor results agree with established LEP measurements, providing a consistency check on the flavor separation. The analysis demonstrates how modern flavor-tagging techniques can be applied to archival LEP data to revisit the flavor structure of hadronic Z decays and precision studies of light-quark production in QCD. Response calibration, rather than counting statistics, limits the precision.

Speaker: Shuo Han (IHEP (高能所))

19 Dihadron Fragmentation as a Spin Analyzer at Lepton Colliders

Spin-dependent dihadron fragmentation provides a unique way to access the polarization and spin correlations of light quarks and gluons at lepton colliders. In this talk, I will discuss how dihadron fragmentation can serve as a spin analyzer and be used to study a range of phenomena, including Bell inequality violation, anomalous electromagnetic dipole interactions, light-quark Yukawa couplings, and the color-octet mechanism in bottomonium decays. I will also show how the same framework can be extended from quark transverse spin to gluon linear polarization. These studies demonstrate that dihadron fragmentation offers a versatile probe of otherwise inaccessible partonic spin information and its underlying dynamics.

Speaker: Prof. Bin Yan (IHEP)

20 Leaves-to-Tree: Deep-Learning Reconstruction of K_S^0 and Λ from Charged Tracks at CEPC

Identified light-hadron production in Z→qq̄ events — K_S^0, Λ, φ, K⁰ and ρ⁰ — is sensitive to quark fragmentation, strangeness suppression and vector-meson production, and its precision at CEPC is limited by the reconstruction of the corresponding two-body decays from charged tracks. This contribution presents a deep-learning implementation of the "leaves-to-tree" step at CEPC: neutral hadrons are reconstructed directly from charged tracks using ParT. Focusing on the benchmark channels K_S^0→π⁺π⁻ and Λ→pπ⁻, the reconstruction efficiency, the purity and their product are compared with the conventional cut-based reconstruction, both integrated and as a function of the reconstructed energy. Extensions to the prompt resonances φ, K⁰ and ρ⁰ and to multi-body decays, and the prospects for precision measurements of identified-hadron production at the Z pole, are also discussed.

Speaker: 嵩 潘 (上海交通大学)

Sustainability in HEP: 1

Friday Afternoon: Function Room 11
Zoom Link, ID: 934 7906 6977, Code: 522727

Monday Morning: Junior Ballroom I
Zoom Link, ID:99229612134, Code: 887914

3:30 PM Coffee break

AI & Machine Learning in HEP: 1

Zoom Link, ID: 934 7906 6977, Code: 522727

21 Optimal Binning from Optical Binning: a Machine Learning Approach

We will describe progress along simulation based inference in the precision era.

Speaker: Lingfeng Li (Brown University)

22 AI for High Energy Phenomenology — What’s next?

Artificial intelligence has rapidly become an integral part of high-energy physics, evolving from specialized machine-learning tools for individual analysis tasks toward increasingly general and large-scale models for scientific data. As this field enters a new stage, an important question is not only how to build more powerful models, but also what we can learn from the models themselves. In this talk, I will review recent developments in AI for high-energy phenomenology, with a particular focus on collider physics and the emerging paradigm of foundation models. I will then discuss ongoing efforts to probe the internal representations learned by these models, using geometric approaches to study how their representations evolve during training and across architectures. More broadly, I will argue for a perspective on Scientific AI in which AI is not merely a computational tool for solving predefined physics tasks, but can increasingly serve as a new instrument for uncovering physical structures from the data itself.

Speaker: 恬吉 蔡 (同济大学)

23 AI scientist for LQCD: a new tools at CEPE

This talk introduces LQCDMaster, an AI agent framework that turns natural-language physics requests into executable lattice QCD workflows. Combining physics planning, PyQUDA code generation, automated debugging, and GPU execution, it supports a range of hadronic observables. We present its architecture and assess its reliability through numerical validation against expert-written reference programs.

Speaker: Wei Wang (SJTU)

24 Agentic AI and Deep Learning at BESIII

This talk provides an overview of recent advances in agentic AI and deep learning at BESIII. I will introduce DrSai, a multi-agent system designed for autonomous end-to-end physics analysis—from natural-language goals to data selection, statistical inference, and systematic evaluation—with emphasis on reliability, traceability, and human-AI collaboration. I will also overview our deep-learning efforts, including an experimental-data foundation model, SAM-based reconstruction of intermediate resonances, and machine-learning-based beam-background suppression in the BESIII trigger. Finally, I will discuss the evolving role of AI—from an efficiency tool to an active reasoning partner in scientific discovery—and how human-AI collaboration can accelerate high-energy physics and beyond.

Speaker: Dr Ke LI (IHEP)

25 Agentic AI for Particle-Physics Detector Operations: Towards an AI-Assisted Shifter

Modern particle-physics detectors require continuous monitoring, rapid anomaly detection, and timely expert response. This contribution presents an Agentic AI framework for intelligent detector operations, integrating sensor information, automated anomaly detection, contextual interpretation, and decision support.
Environmental and operational sensor data are analysed using Agentic AI tools that generate alerts, interpret detector conditions, and provide recommendations to experts and shifters. The framework is also being extended to Data Quality Monitoring through autoencoders applied to detector monitoring histograms.
Agentic AI is used to interpret anomalies in context, correlate information from multiple monitoring sources, and recommend possible actions. This approach represents a step towards an AI-assisted shifter and provides a pathway to intelligent monitoring for current and future high-energy physics facilities.

Speaker: Bruce Mellado (IHEP)

26 A Human-Governed Agentic Workflow for HEP Analysis: Design, Skills, and Evaluation

Recent coding agents can execute increasingly complex scientific workflows, but realistic high-energy physics (HEP) analyses remain nonlinear and require domain expertise, systematic validation, reproducible evidence, and human scientific judgment. We present a human-governed, skill-oriented workflow for agent-assisted HEP analysis. Native coding agents perform planning, coding, computation, validation, and documentation, while reusable Skills provide HEP-specific methods and checks on demand. Rather than imposing a dedicated orchestrator or fixed workflow graph, the approach builds on native agent capabilities and composes Skills according to the task and its risks. Human researchers retain scientific authority and review versioned evidence and analysis packages through GitLab. We demonstrate the workflow through a joint measurement of Rb, Rc, and Rs using LEP Open Data, and introduce evaluations ranging from Skill activation tests to blinded full-analysis benchmarks derived from real analysis history. These studies explore how agent autonomy, domain knowledge, and human oversight can be combined for reliable and reproducible HEP analysis.

Speaker: Shuo Han (IHEP (高能所))

Accelerator: 6

Zoom Link, ID: 94805716496, Code: 217749

Physics Beyond SM: 2

Friday Morning: Function Room 11
Zoom Link, ID: 934 7906 6977, Code: 522727

Friday Afternoon and Saturday Morning: Junior Ballroom I
Zoom Link, ID:99229612134, Code: 887914

27 Probing the Real Triplet Higgs Model with Higgsstrahlung at future $e^+e^-$ colliders

Speakers: CRISTIAN SIERRA (上海交通大学), Cristian Sierra (TDLI)

28 2HDMs with extended U (1) gauge symmetry at current and future colliders

Speakers: Xinran XU (The Hong Kong University of Science and Technology), Xinran Xu (hkust)

29 H-COUP developments

Speaker: kodai sakurai

30 Status of New Higgs Boson Candidates at the LHC,

Speakers: Bruce Mellado (IHEP), Bruce Mellado (University of the Witwatersrand)

31 An opportunity to measure Bf (Z→ nu_e nu_e_bar) with a high accuracy at CEPC

Speakers: Alexey Drutskoy (LPI), Alexey Drutskoy (LPI)

32 Testing Bell inequalities and probing quantum entanglement at CEPC

Speaker: Alim Ruzi (school of physics Peking Uniersity)

Silicon Detectors: 3

Zoom Link, ID: 91011235165, Code: 983836

Plenary: Public Lecture

Thursday Morning: Grand Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

Monday Afternoon: Junior Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

33 TBA

Speaker: Yifang Wang (高能所)

34 TBA

Speaker: Liantao Wang (University of Chicago)

Saturday, October 24

Accelerator: 7

Zoom Link, ID: 94805716496, Code: 217749

MDI, Mechanics & Integration: 1

Saturday Morning: Junior Ballroom III
Zoom Link, ID: 91011235165, Code: 983836

Saturday Afternoon: Function Room 10
Zoom Link, ID: 94805716496, Code: 217749

35 CEPC Interaction Region engineering design status of MDI

Speaker: Haijing Wang (高能所)

36 CEPC SCQ cryostat design

Speakers: 啸辰 杨 (高能所), 张祥镇 ZHANG Xiangzhen (高能所)

37 LumiCal for luminosity and precision test of QED

Purpose: Small-angle Bhabha scattering of e+e- → e+e-(nγ) has a very large cross-section and is a favorable process for measuring e+e- collision luminosity. The theoretical precision is approaching 10-4. The experimental measurements of radiative Bhabha interactions have been achieved at the 1 % level. We present Monte Carlo simulations using BHLUMI and BHWIDE programs to estimate the detection of radiative photons for higher-order contributions.

Methods: Future collider projects are proposed for flavor facilities and Higgs factories of the FCC-ee and the CEPC. Luminosity detectors are proposed as precision luminometers for detection of the well-predicted Bhabha scattering events. The LumiCal is designed within the Machine-Detector Interface (MDI) region on both sides of the Interaction Point surrounding the beam-pipe before the quadrupole magnets. Bhabha scattering events are simulated for center-of-mass energies of 91 to 360 GeV for Higgs factories. The Bhabha cross-sections and the distributions of radiative photons are compared.

Results: Radiative photons are generated with the Yennie–Frautschi–Suura (YFS) exclusive exponentiation method. The event rates of photons with energies near zero are compatible independent of the electron energies. Photons are populated surrounding the incident or scattered electrons. The e/gamma identification is conducted with silicon sensors to detect electrons and LYSO arrays for shower clusters of electrons and photons. The segmentation of LYSO arrays separating shower clusters can distinguish e/gamma with an opening angle of more than 2 cells (~10 mrad). The photon event rates and angular distributions can be measured for higher-order terms in QED.

Conclusion:
The exclusive measurement of radiative photons in Bhabha events. The goal is for 10-4 precision on Bhabha event counting at future collider projects.

Speaker: Suen Hou (IPAS)

38 EMD in integrated luminosity measurement at the Z-pole

In order to ensure measurement of the integrated luminosity with a relative precision of 10−4 at the Z0 pole at CEPC, numerous systematic effects have to be quantified and corrected for. Here we discuss collective impact of electromagnetic bunch fields on the initial state electrons and positrons as well as on the final states produced in Bhabha scattering. These effects change four-momenta of the final state particles, leading to modification of Bhabha count in the instrumented volume. Size of the counting loss is quantified in simulation, and experimental method based on machine learning is discussed in order to correct for this loss.

Speaker: Ivanka Bozovic (Vinca Institute of Nuclear Sciences)

39 Development of 4H-SiC Low-Gain Avalanche Diode (SICAR3) for the CEPC Fast Luminosity Detector

The Circular Electron Positron Collider (CEPC) requires a fast luminosity detector to achieve a relative measurement precision of 2% at a sampling rate of 1 kHz in order to drive a real-time orbit feedback system, due to its extremely high luminosity. 4H-SiC, with its wide bandgap, high displacement threshold energy, and high saturated electron drift velocity, simultaneously offers excellent radiation hardness (particularly its superior tolerance to gamma rays), picosecond-level time response, and low leakage current at elevated temperatures. These properties make it perfectly suited for the extreme environmental demands of fast luminosity detection in the forward region of CEPC.

This work reports on the development progress of the 4H-SiC Low-Gain Avalanche Diode (SICAR3). The device fabrication is based on a mature 350 nm MOSFET process platform. The SICAR3 achieves an avalanche gain of 10–15 and a time resolution improved to 60 ps. In terms of key design, the device directly adopts a high-temperature ion-implanted Junction Termination Extension (JTE) as the termination structure, which effectively suppresses leakage current and overcomes the limitation on the usable active area. The successful tape-out of SICAR3 lays a solid foundation for the engineering application of large-area, low-leakage 4H-SiC LGADs for the CEPC fast luminosity detector.

Speaker: Xiyuan 希 媛 Zhang 张

Offline Computing & Software: 1

Zoom Link, ID: 934 7906 6977, Code: 522727

Physics Beyond SM: 3

Friday Morning: Function Room 11
Zoom Link, ID: 934 7906 6977, Code: 522727

Friday Afternoon and Saturday Morning: Junior Ballroom I
Zoom Link, ID:99229612134, Code: 887914

40 Searching for dark photons from dark-scalar decays at CEPC and FCC-ee

Speakers: Zeren Simon (泽人) Wang (王) (Hefei University of Technology), Zeren Simon Wang (University of Bonn)

41 Quantum information of photon pairs at lepton colliders

Speaker: Prof. Bin Yan (IHEP)

42 Tera-Z as a discovery machine

Speaker: Juraj Klaric

43 Optimisation of the vertex detector and measurement of Higgs decays to second-generation quarks at the CEPC

Speaker: 家琳 李 (上海交通大学)

10:30 AM Coffee break

Accelerator: 8

Zoom Link, ID: 94805716496, Code: 217749

Electronics & Readout Systems: 1

Zoom Link, ID: 934 7906 6977, Code: 522727

44 Requirements and status of the CEPC Electronics system

Speaker: Jingbo Ye

45 Serial Powering for the Front-End Electronics

The pixel density of the front-end detectors continues to rise, and with it the power they consume—now stretching into the watt range—while the cable mass and thermal budget of the detector volume remain essentially fixed. Today's arrays are powered in parallel at low voltage and high current (roughly 2 V/24 A), a scheme that already strains the cable budget and the associated I²R losses. This work moves to serial (constant-current) powering: a single input of 48 V/1 A uses high voltage and low current to cut cable losses, which is especially attractive in the strong solenoid field and under a strict noise budget. Serial powering removes the cable problem but brings its own set of challenges: shunt-branch dissipation, an uncontrolled open circuit that can take down the whole chain, a floating local ground with no shared reference, and added noise. These are precisely the difficulties already encountered in the ATLAS serial-powering schemes.
Candidate conversion topologies are reviewed and compared: buck DC-DC, switched-capacitor, shunt LDO, and hybrid combinations. A buck is efficient at a small step-down ratio, but its switching-node parasitics grow as the ratio increases, and magnetic-core inductors do not survive the field; small air-core parts remain a workable fallback. Switched-capacitor converters are compact and fixed-ratio, but they are inefficient at large conversion ratios and need many capacitors and high switching frequencies. Two hybrid approaches are proposed. The first is a delta-modulated switched-capacitor stage followed by an LDO: it needs no inductor, operates in series, and reaches about 80% efficiency at roughly 500 µV ripple, though redundancy and the LDO dropout limit its transient response. Replacing that stage by a switching constant-current capacitor, a hybrid buck, and an ultra-low-dropout LDO requires only a small air-core inductor (~0.5–1 µH), reaches above 90% at about 100 µV ripple, and trades current margin for voltage margin, giving good short-burst response without sacrificing efficiency.
A 1.1 A four-stage simulation, with 1.8 V and 1 A per stage and a 60 dB LDO gain, is used to model the rail build-up, constant-current capacitor charging, and final LDO settling. Two demo boards confirm the concept in hardware, including a version built around an 80 V/10 A GaN power stage, a 1 MHz buck with an 8 A NMOS, and a 1.5 A LDO with 150 mV dropout. Results show a stable serial chain settling to a 3.3 V rail and successful cascaded charging.
Three key issues specific to serial powering are addressed. Because the reference ground floats along the chain, the HV MAPS substrate, which must be back-biased to −70 V to fully deplete the bulk (versus about −6 V in conventional MAPS), requires each die to generate its own independent bias voltage for collection efficiency; the simulation confirms a monotonic bias from −70 V to −58 V across five dies while keeping the local substrate voltage constant. To survive an open circuit, DTI isolation separates three independent voltage domains (pixel/power, bias generation, and inter-stage detection), so that a stage can be shorted locally through a redundant path before it trips on over-voltage, keeping the chain current stable. Finally, spread-spectrum suppression lowers the EMI peaks introduced by switching. For data transport across the floating ground, an AC-coupled LVDS link provides a ground-fault-tolerant serializer channel, and transmission is gated off during power-rail switching, occupying less than 1% of the transmission time to secure signal stability.
Future work integrates the hybrid buck with inter-stage coordination to raise transfer efficiency, adds the ultra-low-dropout LDO and open-circuit monitoring, evaluates noise levels and sources, and considers radiation effects and radiation hardening.

Speaker: Dr Yue Zao (Nankai University)

46 A 20.48-Gbps PAM4 transmitter with 2-tap FFE in 55 nm for high-energy physics experiments

High-energy physics experiments require increasingly high-speed data transmission in front-end readout systems. Based on our prior designs and measurements, the 10-Gbps NRZ transmission is approaching the bandwidth limit of the 55-nm CMOS process. Consequently, PAM4 transmission technology, which doubles the data rate within the same analog bandwidth, presents an attractive alternative.
The proposed PAM4 transmitter comprises a phase-locked-loop (PLL), two 16:1 CMOS-logic serializers (MSB and LSB), current mode logic (CML) buffers, voltage-controlled delay cells (VCDLs), a PAM4 combiner, digital-to-analog converters (DACs) and a serial peripheral interface (SPI). The PLL and serializer circuits have been silicon-verified. To reduce area in the initial prototype, a much smaller PRBS7 pattern generator is used instead of the serializer, and the PLL is replaced by an external-clock receiver (equalizer).
The PAM4 combiner merges the MSB and LSB channels into a single data stream, providing an output current of 3 mA at a single eye height and a programmable biasing current for the vertical-cavity surface-emitting laser (VCSEL) ranging from 0.4 to 9.8 mA. A variant incorporating a peaking inductor is also implemented. The MSB channel consists of two identical LSB channels, each featuring a two-tap CML structure (referred to as the main tap and the post tap). The feed-forward equalizer (FFE) operates as a transversal filter based on a tapped delay line and the combiner. In the LSB channel, the main tap, driven by the original signals, serves as the driving stage with a tail current (M5) of about 6 mA. The post tap functions as the equalizing stage and is driven by the delayed signals. The FFE weight coefficient can be adjusted via a 4-bit tail current source (M6-M9) from 0 to 1.5 mA in 0.1-mA step. The tap delay is configured by a 10-bit DAC, providing a tuning range from 27 ps to 97 ps. By adjusting the weight coefficient and tap delay, an optimal eye opening can be achieved for a certain range of the channel loss.
Preliminary electrical test results indicate that the PAM4 transmitter operates correctly up to 20 Gbps. The three measured eye heights are 177, 193, and 193 mV after FEE (level-7), respectively. The overall power consumption is about 68.4 mW, including 15 mW (simulated) for the PRBS generator, 24 mW for the combiner alone, and the remaining power for the adjustable delay line operating with a 0.6-V control voltage.

Speakers: Mr Guorui Zhang (IHEP), Xiaoting Li (高能所)

47 Design of a Large-Area MRPC Readout Electronics System with High Granularity and High Timing Precision

Speaker: Weihao Wu (Shanghai Jiao Tong University)

48 The Peripheral Electronics Board - a Component of the HGTD In-detector Electronics for the ATLAS Phase-II Upgrade (remote)

Speaker: Jie ZHANG (Institute of High Energy Physics)

Flavor Physics: 1

Zoom Link, ID:99229612134, Code: 887914

49 LHCb flavour highlights and prospects

Speaker: Zehua Xu (CERN)

50 BESIII flavour highlights and prospects

Speaker: Prof. Liang Sun (Wuhan University)

51 Lepton-Flavour-Violating Axion-Like Particles at Future Colliders

Axion-like particles (ALPs) with lepton-flavour-violating couplings provide a distinctive opportunity to search for new physics at future high-energy and flavour facilities. I will discuss the phenomenology of ALPs above the muon threshold, where the decay a→eμ becomes kinematically accessible and can lead to striking signatures with very small Standard Model backgrounds. I will focus on ALP production in charged-meson, W, Z, quarkonium and τ decays, and discuss the prospects for probing these interactions at future e+e− colliders and flavour factories, complemented by fixed-target and beam-dump experiments. Particular emphasis will be given to the sensitivity of future facilities and to the interplay between different production channels and existing low-energy constraints.

Speaker: Marco Fedele

Future Experiment Proposals: 1

Zoom Link, ID: 91011235165, Code: 983836

52 The AGORA detector

Speaker: Yiming 一鸣 Li 李 (IHEP)

53 The IDEA detector

Speaker: Franco Bedeschi (INFN-Pisa)

54 The CLD detector

Speaker: James Brau (University of Oregon)

12:30 PM Lunch break

Flavor Physics: 2

Zoom Link, ID:99229612134, Code: 887914

55 The Impact of RICH Detector on Flavor Physics at CEPC

Particle identification (PID) is important for the flavor physics analysis at future $e^+e^-$ colliders. Efficient $K/\pi$ separation can improve the reconstruction of exclusive heavy-flavor decays and suppress backgrounds from particle misidentification. A Ring Imaging Cherenkov (RICH) detector is therefore being studied to provide additional PID capability in the forward and backward regions of the CEPC detector.

The forward and backward RICH geometries and their track acceptance are implemented in the CEPC detector simulation. Momentum- and angular-dependent PID response matrices are applied to charged tracks to model kaon and pion identification efficiencies and misidentification probabilities. Using CEPCSW-based simulated heavy-flavor samples at the $Z$ pole, the RICH kinematic coverage, geometrical acceptance, and PID performance are evaluated, together with their impact on signal efficiency and $K/\pi$ misidentification backgrounds.

These studies provide input for optimizing the RICH design and assessing its impact on CEPC flavor-physics measurements.

Speaker: 梓秋 杨 (Jilin University)

56 Lattice QCD calculation of $\Xi^{-}\rightarrow\Lambda\ell^{-}\bar{\nu}_{\ell}$ semileptonic decay

We present the first principle calculation of $\Xi \rightarrow \Lambda$ form factors employing 2 + 1 flavor gauge ensembles with lattice spacings ranging from 0.06 to 0.1 fm and pion masses between 230 and 340 MeV.

Speaker: 磊毅 李 (海南师范大学)

57 Automating SU(3) Flavor-Amplitude Analysis with an AI Agent

We present an AI agent designed to automate SU(3) flavor-amplitude analyses of hadronic weak decays. Starting from a specified decay process, the agent identifies the relevant SU(3) multiplets and effective weak Hamiltonian, constructs independent invariant contractions, and converts them into amplitudes for physical decay channels. It also performs consistency checks, searches for amplitude relations, and identifies experimentally unexplored SU(3)-related processes. As an illustrative application, we discuss three-body nonleptonic decays of bottom baryons. This framework aims to make extensive SU(3) calculations more efficient, reproducible, and less susceptible to algebraic errors.

Speaker: 吉 徐 (兰州大学)

58 Minimal Flavor Protection

MFP is a new flavor-symmetry spurion framework that provides minimal protection for generic new physics at the TeV scale to satisfy stringent FCNC bounds. It lies at the opposite end of the spectrum from the well-established MFV, opening up a broader landscape of flavor-safe TeV-scale models. Its defining features—maximal universality violation and flavor-charged currents—can both be effectively probed at a future e+e- collider. The talk is based on 2512.04159 and related work.

Speaker: Admir Greljo

Future Experiment Proposals: 2

Zoom Link, ID: 91011235165, Code: 983836

59 The ILD detector

Speaker: Mary-Cruz Fouz Iglesias (CIEMAT)

60 The ALFA detector

Speaker: Duccio Abbaneo

61 The ALLEGRO detector

Speaker: Emmanuel Monnier (CPPM)

MDI, Mechanics & Integration: 2

Saturday Morning: Junior Ballroom III
Zoom Link, ID: 91011235165, Code: 983836

Saturday Afternoon: Function Room 10
Zoom Link, ID: 94805716496, Code: 217749

62 Manufacturing and Experiment of Ultra-Light Carbon Fiber Composite Unidirectional Heat Conductive Cold Plate

This work focuses on the development of cold plate components for the CEPC detector. An ultra-light carbon fiber composite unidirectional heat conductive cold plate was manufactured by hot-pressing carbon fiber and graphene, and its thermal conductivity was optimized. The resulting cold plate exhibits a density lower than that of aluminum and a thermal conductivity higher than that of aluminum, making it suitable for low-material-budget detector applications. In addition, a thermal conductivity measurement method was investigated, and an experimental setup was established to measure the thermal conductivity of ultra-thin plates with a thickness of approximately 0.3 mm. This work provides reliable equipment support for further optimizing the thermal conductivity of the cold plate and experimentally verifies the feasibility of the proposed ultra-light cold plate for CEPC detector thermal management.

Speaker: xiaohui qian (高能所)

63 Status of Calorimeter mechanical design

An harmonious calorimeter idea has been proposed. We designed a new structure of ECAL and HCAL. More detailed structure information will be introduced in this report. A new cooling scheme has been proposed and test also has been carried out.

Speaker: 亚田 裴 (高能所)

64 Study on Heat Dissipation Performance of the Central Beam Pipe of CEPC

The contents include:
1.Current research status of beam pipes at home and abroad.
2.Background introduction of the CEPC central beam pipe.
3.Structural design of the central beam pipe.
4.Simulation of heat dissipation for the central beam pipe.
5.Progress in fabrication of experimental specimens for the central beam pipe.
6.Implementation of subsequent heat dissipation experiments on the central beam pipe.

Speaker: 健 王 (中国科学院高能物理研究所)

65 Preliminary air cooling test of the VTX thermal mockups

preliminary air cooling test results of the VTX thermal mockups .

Speaker: Mr Jinyu Fu (高能所)

66 Experimental studies for an air cooling system for the FCC-ee inner vertex

The inner vertex detector of the IDEA detector concept is based on MAPS technology, and is expected to dissipate less than about 50 mW/cm2. With such low power density air-cooling solutions can be developed. Two main mechanical arrangements for the silicon sensors are envisaged at the moment:a ‘traditional’ flat version, in which MAPS are put on top of a carbon fibre stave, and a curved sensor version, inspired to the ALICE ITS3 vertex detector. Preliminary simulations of the former geometry show that air-cooling can be successfully employed to maintain temperature control along the full length of the stave, which in the case of the longest structures are of the order of 50 cm dimensions,
although with a considerable air-flow, that in turn induces vibrations smaller than the single hit resolution of the MAPS (~3 μm). The mechanical layout of such a solution should guarantee sufficient air-cooling capabilities and keep the mechanical structure vibrations at the minimum.
To validate the effectiveness of this approach, a dedicated experimental setup has been implemented,enabling precise measurements of pressure, temperature, and flow rate within the test section for both single-layer and multi-layer configurations. The experimental system provides essential feed-back to the parallel computational fluid dynamics (CFD) studies, ensuring accurate data interpretation and reliable modelling of the airflow behaviour around the vertex detector staves. The presentation will provide a description of the mechanical and thermal solutions adopted to establish a hermetically sealed volume within the test section, in which cable routing constraints, together with the requirement to ensure efficient assembly and disassembly procedures, have represented significant technical challenges.
Presentation of the results on air-cooling performance as a function of the air-flow obtained by experimental measurement will be presented, and critically discussed.

Speaker: Gherardo Ammirabile (Universita & INFN Pisa (IT))

Offline Computing & Software: 2

Zoom Link, ID: 934 7906 6977, Code: 522727

3:30 PM Coffee break

EW and top Physics: 1

Zoom Link, ID:99229612134, Code: 887914

Electronics & Readout Systems: 2

Zoom Link, ID: 934 7906 6977, Code: 522727

Gaseous Detectors: 1

Zoom Link, ID: 91011235165, Code: 983836

MDI, Mechanics & Integration: 3

Saturday Morning: Junior Ballroom III
Zoom Link, ID: 91011235165, Code: 983836

Saturday Afternoon: Function Room 10
Zoom Link, ID: 94805716496, Code: 217749

67 FCC-ee MDI Status

Speakers: Manuela Boscolo (INFN), Manuela Boscolo (INFN Laboratori Nazionali di Frascati)

68 Beam loss and collimation studies at FCC-ee

Speaker: Giacomo Broggi (CERN, Sapienza Università di Roma e INFN Laboratori Nazionali di Frascati)

69 Status and Perspectives for FCC-ee Detector Background Studies

70 The Study Status of CEPC MDI at EDR Phase

The machine-detector interface (MDI) issues are one of the most complicate and challenging topics at the Circular Electron Positron Collider (CEPC). Comprehensive understandings of the MDI issues are decisive for achieving the optimal overall performance of the accelerator and detector. The machine will operate at different beam energies, therefore, a flexible interaction region design will be plausible to allow for the large beam energy range. The design has to provide high luminosity that is desirable for physics studies, but keep the radiation backgrounds tolerable to the detectors and other related sub system components. This requires careful balance of the requirements from the accelerator and detector sides.
In this work, the latest design of the CEPC MDI and the study status of the beam induced backgrounds based on CEPC Technical Design Report (TDR) of the accelerator and the reference detector will be presented, covering the design of the beam pipe and whole IR, the estimation of beam induced backgrounds, the mitigating schemes, and also our plan towards the EDR of accelerator

Speaker: Dr Haoyu SHI (IHEP)

71 Impact of Beam-Induced Background on Time Projection Chambers at Future e+e- Colliders

In recent years, several next‑generation large‑scale scientific facility plans based on electron‑positron colliders have been successively launched in the field of international high‑energy physics (FCCee, CEPC, ILC, etc.). In the published conceptual designs of accelerators and detectors, the Time Projection Chamber (TPC) is widely selected as the main tracking detector owing to its unique technical advantages. The potential impact of beam background on the TPC drift electric field uniformity under high‑luminosity operating conditions is an important research direction that requires careful evaluation. Detailed studies in collaboration with the MDI collaboration are necessary to fully assess this aspect for the application of TPCs in future high‑energy collider experiments.

This study systematically evaluates beam-background effects on high-granularity readout Time Projection Chamber Detection technology for future electron-positron colliders, using a Geant4-based background simulation scheme equivalent to that adopted by the FCCee collaboration. A comprehensive framework covering multiple space-charge sources is developed, together with theoretical models for space-charge density, electric-field distortion, and electron-drift deviation. Secondary low-energy photons generated by beam background are identified as the primary space-charge source, with key physical parameters quantified under both Higgs and low-luminosity Z operation modes. An integrated solution combining interaction-region design optimization and dedicated correction algorithms is proposed to address the associated momentum-resolution effects. The optimized CEPC interaction-region design constrains the space-charge density below 1.0 nC/cm², keeping electron-drift deviations within 100 μm over most of the TPC chamber, while the correction algorithm effectively restores momentum-resolution performance. These results provide important theoretical and technical support for TPC applications in future high-energy collider experiments.

Speaker: Jianbo Zheng (高能所)

72 Zero Degree Calorimeter for BESIII

This talk will present the latest status of Zero Degree Calorimeter at BESIII. The structure of ZDC is inspired by the CEPC LumiCal which is made of Lyso crystal and SiPM.
Its primary goal is to measure the instantaneous luminosity of BEPCII and can be extended to tag the ISR photon.

Speakers: yuhui miao, 雷(Lei) 张(Zhang) (南京大学(Nanjing University))

73 Developing Status of CEPC Detector Magnet

The developing progress of the CEPC detector magnet is introduced in the report, including the Box-type aluminum stablized NbTi Rutherford cable and HTS cable.

Speaker: Feipeng NING (IHEP)

6:30 PM Banquet

Sunday, October 25

Accelerator: 9

Zoom Link, ID: 94805716496, Code: 217749

EW and top Physics: 2

Zoom Link, ID:99229612134, Code: 887914

Gaseous Detectors: 2

Zoom Link, ID: 91011235165, Code: 983836

PID & Emerging Technologies: 1

Zoom Link, ID: 934 7906 6977, Code: 522727

10:30 AM Coffee break

Posters: 1

12:30 PM Lunch break

2:00 PM Free time

Monday, October 26

Accelerator: 10

Zoom Link, ID: 94805716496, Code: 217749

EW and top Physics: 3

Zoom Link, ID:99229612134, Code: 887914

PID & Emerging Technologies: 2

Zoom Link, ID: 934 7906 6977, Code: 522727

TDAQ & Online Computing: 1

Zoom Link, ID: 91011235165, Code: 983836

Conveners: Dr Fei Li (EPC, IHEP), Miroslav Saur (Lanzhou University)

74 Enhancement of the Belle II High Level Trigger Using GPUs

With the increasing luminosity of SuperKEKB, the background rate in
the Belle II detector is expected to increase, potentially exceeding
the processing capacity of the current High Level Trigger (HLT)
system. To mitigate the HLT processing load, we are developing a
GPU-based pre-filtering system that performs part of the event
reconstruction on GPUs before the conventional HLT processing. We have
integrated CUDA into the Belle II software framework to establish a
seamless execution environment across GPUs and CPUs. In this
presentation, we will report on the current status and progress of the
development.

Speaker: Prof. Ryosuke Itoh (KEK)

75 The incoherent pair production simulation study

Incoherent electron–positron pair production, commonly referred to as beamstrahlung, constitutes the dominant beam-induced background for the CPEC, accounting for more than 95% of the total background events. Reliable modeling of this process is therefore essential for both detector response estimation and trigger system design. At present, the Guinea-Pig simulation package is employed to generate this incoherent pair-production background. To validate the Guinea-Pig predictions, we analyze open data from the DELPHI experiment at LEP1 and LEP2 to measure the production cross section and momentum distribution of the produced pairs, and we compare these measurements with the corresponding simulation results.

Speaker: Boping Chen

76 L1 trigger hardware design progress on CEPC ref-Detector

The Circular Electron–Positron Collider (CEPC) will pursue a broad physics program by operating at several center-of-mass energies and luminosity levels, including Higgs, Z, and W-pair modes. This range of operating points places diverse requirements on the detector and its trigger and data acquisition (TDAQ) system. The trigger system is organized into two levels: a Level-1 (L1) trigger for real-time hardware-based event selection and a High-Level Trigger (HLT) for subsequent event processing. At the heart of the L1 system is the trigger data-processing module, which must handle data from multiple sub-trigger systems while meeting stringent requirements on throughput, latency, and flexibility. I. These requirements motivate the development of a shared and adaptable processing platform.To address this need, we have developed a common trigger data-processing module intended for use across the CEPC sub-trigger systems. By sharing a common hardware platform, the design aims to streamline development, integration, operation, and maintenance while allowing the same module to be adapted to different trigger applications. The module is implemented in the Advanced Telecommunications Computing Architecture (ATCA) form factor and is centered on an AMD Virtex UltraScale+ field-programmable gate array (FPGA). Eleven Quad Small Form-factor Pluggable (QSFP) modules provide 44 high-speed lanes, each supporting data rates of up to 25 Gb/s. The module also incorporates 16 GB of Double Data Rate (DDR) memory to support temporary event buffering for hundreds of milliseconds, together with an Intelligent Platform Management Controller (IPMC) and a K26 system-on-module (SOM) for board-level management and control. To date, a series of board-level functional tests has been carried out on the prototype module, covering the on-board power supply and distribution subsystem, clock distribution, FPGA configuration ,gigabits transceiver(GT) links, and DDR. The results obtained from these tests are consistent with the expected behavior of the corresponding subsystems. Testing of the K26 SOM-related functionality remains ongoing . Together, the module design and the completed tests provide a common hardware foundation for future L1 trigger-firmware integration, system-level verification, and adaptation to the requirements of different CEPC sub-trigger systems and operating modes.

Speaker: dong Liu (中国科学院高能物理研究所)

77 Development and Evaluation of an FPGA-Based RoCEv2 Protocol Stack for High-Throughput Data Transfer in Detector Readout Systems

Modern particle physics detectors contain many readout channels that continuously produce large amounts of data. These data must be transferred from back-end electronics to readout servers with high bandwidth and low latency while keeping CPU processing and memory-copy overhead low. This work presents an FPGA-based RoCEv2 protocol stack designed for detector data readout. The protocol stack uses RDMA to write detector data directly into registered server memory. Versions for 10, 40, and 100 GbE have been developed. The main functions include RoCEv2 packet generation, RDMA Send and Write operations, packet sequence management, iCRC calculation, and data integrity checking. The 10/40 GbE version also supports multiple queue pairs, fault isolation, retransmission, and error recovery. These functions are being added to the 100 GbE version.
The protocol stack was tested on several FPGA platforms with commercial RNICs. The 100 GbE implementation on a Xilinx VCU118 achieved approximately 93.5 Gbit/s in single-QP RDMA Write tests. Preliminary tests also measured a point-to-point latency below 3 μs. The 40 GbE implementation reached 37.4 Gbit/s, corresponding to 93.5% link utilization, and was ported to the ZCU102 platform with similar performance. Its use in a detector readout system was tested during BESIII Main Drift Chamber beam and cosmic-ray runs, where a single readout node sustained a data rate of 13.4 Gbit/s while transmitting full detector data without zero suppression.
The results show that the FPGA-based RoCEv2 protocol stack can work with commercial RNICs and provide near-line-rate transmission for particle physics detector readout. Possible future applications include the CEPC data acquisition system and other high-rate detector systems. Future work will add multi-QP and reliability support to the 100 GbE version, test multiple readout nodes, and develop a remote circular buffer for continuous and reliable data transfer.

Speakers: Sheng Dong (IHEP), 畅 徐 (高能所)

10:30 AM Coffee break

Accelerator: 11

Zoom Link, ID: 94805716496, Code: 217749

PID & Emerging Technologies: 3

Zoom Link, ID: 934 7906 6977, Code: 522727

Sustainability in HEP: 2

Friday Afternoon: Function Room 11
Zoom Link, ID: 934 7906 6977, Code: 522727

Monday Morning: Junior Ballroom I
Zoom Link, ID:99229612134, Code: 887914

TDAQ & Online Computing: 2

Zoom Link, ID: 91011235165, Code: 983836

Conveners: Da Yu Tou (Tsinghua University), Dr Fei Li (EPC, IHEP)

78 Research on GPU Algorithms and Online Computing

The Circular Electron Positron Collider (CEPC) is a next-generation high-energy electron–positron collider. Its Reference Detector will generate large volumes of data, placing demanding requirements on the trigger and data acquisition system. A fully software-based trigger offers flexible deployment, straightforward upgrades, and extensible algorithm support, while introducing substantial computational demands.

This dissertation focuses on online data processing for the CEPC and investigates two key aspects. First, GPU-oriented track-based filtering algorithms are studied and evaluated in terms of physics performance, processing latency, and throughput. Second, a heterogeneous CPU–GPU online computing framework is developed to support time-slice data organization, heterogeneous memory management, and task scheduling, providing a unified and extensible execution environment for online algorithms.

This work provides an algorithmic and software foundation for building a flexible, high-throughput, and sustainable online data processing system for the CEPC.

Speaker: 叙 张 (高能所)

79 Nonlinear Track Reconstruction Studies towards UKF-Based Tracking for CEPC

The development of robust, precise and computationally efficient track reconstruction is important for CEPC offline reconstruction and its future high-level trigger (HLT) development, where tracking algorithms must balance reconstruction performance with the computational demands of large-scale event processing. In particular, charged-particle motion in magnetic fields and interactions with detector material introduce nonlinearities that can affect the estimation of track states and their uncertainties. Motivated by these considerations, this work investigates nonlinear effects within the ACTS-based tracking framework as a step towards the development and evaluation of Unscented Kalman Filter (UKF)-based tracking for CEPC.

As an initial study, we investigate the ACTS FreeToBoundCorrection (FTBC), which supplements the conventional linearised free-to-bound covariance transformation with a correction for nonlinear effects. We found that FTBC was not being applied in the Combinatorial Kalman Filter (CKF) propagation path used in our study and have enabled and systematically evaluated its use. While FTBC provides an additional correction for nonlinear effects not fully captured by the linearised transformation, the underlying filtering approach still relies on conventional linearisation. The UKF, in contrast, propagates sigma points through nonlinear transformations and reconstructs the state and covariance from their transformed distribution, allowing nonlinear effects to be incorporated directly into the estimation process. The FTBC study therefore establishes a baseline for determining whether UKF-based estimation can provide additional advantages.

Controlled simulation studies are used to examine the influence of FTBC on predicted and filtered track states, covariance transport and measurement association. The results show that small FTBC-induced changes in the propagated state and covariance can, under particular trajectory and incidence conditions, alter the source-link selected during combinatorial reconstruction. Selective suppression studies further demonstrate that a correction introduced at an upstream detector surface can influence a measurement-association decision several surfaces later. In a representative trajectory, suppressing the upstream correction removes the later association switch, whereas suppressing corrections at intermediate and switching surfaces does not. These observations demonstrate how small continuous changes in state and uncertainty propagation can interact with discrete decisions in the reconstruction chain.

The dependence of these effects on track momentum and incidence conditions is being investigated, providing a controlled baseline for studies in realistic CEPC detector configurations. Ongoing work will extend the framework towards UKF-based track fitting and reconstruction and compare it with conventional Kalman-filter-based estimation in terms of state accuracy, uncertainty propagation, robustness under nonlinear conditions, measurement association and computational requirements. Such studies will help assess the potential of nonlinear filtering methodologies for future CEPC offline reconstruction and HLT applications.

Speaker: Dr Jahanzeb Akhtar (Glasgow Caledonian University)

80 The LHCb Heterogeneous Framework in Run 3 and Its Evolution Towards Run 4

LHCb's Run 3 trigger is a fully software-based, two-stage system operating at the full 30 MHz bunch-crossing rate, a first for a collider experiment. HLT1, built on the GPU-accelerated Allen framework, performs the real-time reconstruction and selection that reduces the input rate to a manageable level, while HLT2, built on Gaudi, performs the full offline-quality reconstruction on the surviving events. This heterogeneous CPU/GPU model has been a remarkable success: it delivers the physics performance LHCb needs and has proven the viability of GPU-accelerated real-time analysis in a running experiment.

As we look towards Run 4 and Run 5, the computing challenge grows substantially. The most promising path forward is to port more, and eventually most, of the HLT2 reconstruction to GPU, so that the full trigger chain can benefit from the same acceleration that made HLT1 possible. Realising this ambition requires more than porting individual algorithms: it requires a single, coherent framework in which GPU and CPU algorithms can be developed, composed, tested, and run together, rather than the several disconnected execution paths that exist today.

This talk will present LHCb's experience with the Run 3 heterogeneous trigger, the lessons learned from operating two separate frameworks, and the ongoing consolidation effort that unifies them into a single scheduler supporting mixed GPU/CPU sequences. We will discuss the design of this unified framework, the new mechanisms that allow GPU and CPU data to flow between algorithms, and how this positions LHCb to progressively move HLT2 reconstruction onto GPU for Run 4.

Speaker: Arthur Hennequin (CERN)

81 Experience with online processing of the ALICE TPC in LHC Run 3

ALICE is the dedicated heavy-ion experiment at the LHC at CERN.
For LHC Run 3, ALICE upgraded the TPC with a GEM readout to support continuous operation and the recording of all Pb-Pb collisions.
The peak Pb-Pb recording rate increased from around 1 kHz to 50 kHz.
In order to keep up with the increased data rate, ALICE upgraded its whole online computing scheme, and performs full online processing of all recorded data for calibration and for data compression.
ALICE was the first LHC experiment to leverage GPUs for online data processing during LHC Runs 1 and 2.
In Run 3, TPC processing accounts for more than 90% of the total online workload and runs entirely on GPUs.
This includes clusterization, tracking, and compression.
To efficiently use its online processing farm for offline reconstruction when the LHC is not operating, ALICE has been running offline TPC tracking on GPUs since 2023.
Meanwhile, ALICE has offloaded additional reconstruction steps to GPUs to improve the utilization of GPUs during offline reconstruction.
Online track reconstruction of a TPC with continuous readout posed several new challenges, in particular the absense of a priori knowledge of the z position of hits in the TPC.
The talk will give an overview of the novelties of TPC reconstruction in Run 3, and in particular of the challenges of online processing in such high-rate environments.

Speaker: David Rohr (CERN)

12:30 PM Lunch break

Plenary: 3

Thursday Morning: Grand Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

Monday Afternoon: Junior Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

82 The experiment proposals of FCC-ee

Speaker: Paolo Giacomelli (INFN-Bo)

83 BEPCII: Three Decades of Evolution and the Road Ahead

Speaker: Yuan Zhang (IHEP, Beijing)

84 Basic R&D of Superconducting Cavities for Future Circular and/or Linear Colliders

Speaker: Akira Miyazaki

3:30 PM Coffee break

Plenary: 4

Thursday Morning: Grand Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

Monday Afternoon: Junior Ballroom
Zoom Link, ID: 934 7906 6977, Code: 522727

85 Flavor physics at LHCb/Belle II/BES III and opportunity for future Z factory

Speaker: Vincenzo Maria Vagnoni (INFN/Bologna)

86 Quantum Sensing for (low and) high energy particle physics

An overview of ongoing developments and speculative ideas for greatly improved or novel detectors relying on quantum effects and relevant to the field of particle physics will be given. A particular focus will be placed on ideas addressing calorimetry, tracking, timing or other challenges relevant to high energy particle physics experiments, but some low energy applications linked to particle and fundamental physics will be discussed as well.

Speaker: Michael Doser

87 Beam induced background at e+e- collider

Speaker: Daniel Schulte (CERN)

88 Closing