WLCG/HSF Workshop 2026

2 Nov 2026, 11:00 → 6 Nov 2026, 14:35 Europe/Paris

Congress Center - National Reseach Council (CNR Area Territoriale di Ricerca di Bologna)

Alessandro Di Girolamo (CERN), Daniele Cesini (Universita e INFN, Bologna (IT)), David Britton (University of Glasgow (GB)), Tommaso Boccali (INFN Sezione di Pisa)

Welcome to the WLCG/HSF Workshop 2026 at Bologna (Italy) November 2-6 2026

 

Monday 2 November

Registration

Lunch

Plenary Session: Introduction

Conveners: Alessandro Di Girolamo (CERN), Daniele Cesini (Universita e INFN, Bologna (IT)), David Britton (University of Glasgow (GB)), Dr Tommaso Boccali (INFN Sezione di Pisa)

1 Welcome remarks by institutional representatives

2 WLCG Status

Speaker: Dr Tommaso Boccali (INFN Sezione di Pisa)

3 CTA Computing

Speaker: Stefan Schlenstedt

4 Update on technology and costs

Speaker: Dr Andrea Sciabà (CERN)

15:30 Tea Break

Plenary Session: Roadmaps

Conveners: Alessandro Di Girolamo (CERN), David Britton (University of Glasgow (GB)), James Letts (Univ. of California San Diego (US)), Dr Tommaso Boccali (INFN Sezione di Pisa)

5 The WLCG Technical Roadmap

Speakers: Alessandro Di Girolamo (CERN), James Letts (Univ. of California San Diego (US))

6 Discussion

7 Experiment Round Table

New inputs to the WLCG Technical Roadmap (e.g., resource projections, software improvements including GPU offloading, etc.). Up to 10 minutes per experiment.

8 Discussion

Tuesday 3 November

HSF: Common software and software projects

Conveners: Eduardo Rodrigues (University of Liverpool (GB)), Stefan Roiser (CERN)

9 ROOT7: Innovations and Roadmap

ROOT is a framework at the core of experimental software stacks at the LHC, across HEP and beyond. To meet the demanding computing requirements of HL-LHC data processing, in particular storage, memory, and network, the framework is undergoing a major overhaul guided by a clear technical roadmap.
This contribution provides an overview of the project's current status and priorities for LHC Long Shutdown 3 (LS3). Focusing on ROOT's seventh release cycle (ROOT 7), we highlight key innovations across several domains, including code sustainability, obtainability, modular layering, and interoperability with the broader software ecosystem.
Highly relevant details for distributed processing will be discussed in the areas of I/O, new interfaces and re-thought memory management.
Finally, we present updated timelines to align with the wider software and experiment communities, ensuring a coherent path toward Run 4 operations.

Speaker: Danilo Piparo (CERN)

10 cppjit: the next-generation Python-C++ bridge for ROOT and beyond

A large amount of physics analysis today is steered from Python, while the performance-critical code lives in C++. ROOT's Python interface bridges this gap with automatically-generated Python bindings, leveraging the embedded Cling C++ interpreter. This technology was developed externally as the cppyy project. It served the community well, but it relied on ROOT's internal type system, and both projects became cross-dependent. The codebases diverged, feature development stalled, and many long-standing ROOT Python interface bugs, from wrong overload selection to missing modern C++ features, trace back to this design and its heuristic, string-based handling of C++ types.

Recent R&D efforts by the ROOT team and Compiler Research group have rebuilt this layer from the ground up. CppInterOp is a lightweight library on top of LLVM/Clang that provides runtime C++ reflection directly from Clang's own representation and compiling code just-in-time. The cppjit project, successor to cppyy, is built on top of CppInterOp and no longer depends on ROOT. Its first alpha is released as a Python package, and it will become ROOT's backend for automatic Python bindings from release 6.42. We present what this means in practice: faster binding creation and lower memory footprint, the closure of roughly one fifth of all open Python-related ROOT issues, thread-safe use of C++ from Python, and correct handling of advanced C++ idioms. We also discuss why the new architecture is more sustainable, how it prepares ROOT for the transition from Cling to the upstream LLVM Clang-REPL, and how the same CppInterOp layer is already used from other programming languages and environments, making it a shared foundation for scientific software beyond HEP.

Speaker: Aaron Jomy (CERN)

11 Report on the 2026 Google Summer of Code Program

Since 2011, CERN and the HSF have been part of the Google Summer of Code, a program offering paid remote internships with the stated intend of getting beginners and student to start contributing to open source projects. In this contribution, the CERN/HSF organisation admins will give a report on the 2026 edition, which had 26 contributors work on a diverse set of projects. We will discuss highlights and challenges, possible improvements, and how the rise of generative AI for coding has shaped the program.

Speaker: Valentin Volkl (CERN)

12 ROOT in the Python HEP Ecosystem: Interoperability and Packaging

ROOT leverages automatic and dynamic Python bindings that expose its powerful C++ core to the broader scientific Python ecosystem, distributed through Python wheels on PyPI and packages on conda-forge. Given the widespread Python usage in the HEP community, it becomes increasingly important to ensure that ROOT interoperates smoothly with other Python packages and is easy to obtain and depend on.

This contribution discusses ongoing efforts to strengthen ROOT’s participation within the scientific Python ecosystem both in how it connects to other tools and how it reaches its users. On the interoperability side we discuss recent developments across ROOT’s Python Interfaces enabling more Pythonic analysis. On the distribution side we discuss continued modernization and expansion of ROOT’s packaging infrastructure aimed at making ROOT easier to adopt across a wider range of platforms and workflows.

Speaker: Silia Taider (CERN)

WLCG: DC27

Conveners: Johannes Elmsheuser (Brookhaven National Laboratory (US)), Katy Ellis (Science and Technology Facilities Council STFC (GB))

13 General overview, Schedule, Summary of VO rates

Speakers: Alessandra Forti (The University of Manchester (GB)), Johannes Elmsheuser (Brookhaven National Laboratory (US)), Katy Ellis (Science and Technology Facilities Council STFC (GB))

14 Discussion

15 First experiences with new Rucio Data Challenge Injection tool

Speaker: Mario Lassnig (CERN)

16 Networking

Speaker: Shawn Mc Kee (University of Michigan (US))

10:30 Coffee Break

HSF: Sustainable software

Conveners: Eduardo Rodrigues (University of Liverpool (GB)), Stefan Roiser (CERN)

17 heptraining.cern.ch – A catalogue for HEP training resources and events

HEP Training is a new online registry designed to facilitate the discovery and dissemination of HEP-related training materials and events across High Energy Physics experiments, labs and universities. Students, researchers, and educators can have access to a list of curated resources – such as tutorials, guidelines, workshops and training events. These resources are links to  contributions in our growing network of content providers.

Beyond improving educational resource discovery, our platform fosters HEP community engagement by bridging training and recognition, connecting the development of high-quality educational materials with mechanisms that acknowledge and credit their authors.

HEP Training contributes and links together various projects which in turn allows improvements of the current platform. The latter ranges from content exchange between other training catalogues to raising recognition to trainers, scientists and engineers in the realm of research software engineering.

heptraining.cern.ch is currently deployed, maintained and curated at CERN.

In this talk, we will explain the setup and status of the HEP Training platform, the mTeSS-X and EVERSE projects and their interplay, as well as their future developments such as the recognition framework, ensuring appropriate acknowledgment of trainers, whose work is often underrated – yet fundamental – for academic and scientific work.

Speaker: Stefan Roiser (CERN)

18 FAST-HEP Flow: Towards Reproducible Scientific Workflows from Description to Execution

Analysis workflows need to be flexible: different analyses combine data processing, corrections, selections, machine learning, visualisation, and statistical inference in different ways, while the software and computing environments supporting them continue to evolve. Preserving this flexibility while making analyses reproducible and maintainable remains a significant challenge.

We present FAST-HEP Flow, a modular workflow system that separates the description of an analysis from the software components and infrastructure used to execute it. Analysis descriptions are compiled into explicit execution plans, allowing dependencies to be validated before processing and provenance to be recorded throughout the workflow. Individual operations, data sources, storage technologies, and execution mechanisms can be replaced without redesigning the workflow.

Developed from analysis use cases across multiple experiments, Flow aims to support diverse analysis patterns without prescribing a particular software stack. The separation between analysis description and execution also provides a natural boundary for exploring interoperability with existing workflow and computing infrastructure.

Speaker: Dr Luke Kreczko (University of Bristol (GB))

19 EVERSE Project: Tools and Resources for Research Software Quality

EVERSE (https://everse.software/ ☍) is a community-led, EU-funded project bringing together 18 European institutions to establish a framework for research software quality and code excellence. Collaboratively designed by research communities, EVERSE aims to drive a cultural shift where research software is recognised as a first-class citizen of the scientific process and its contributors are duly credited. We will present the tools and resources EVERSE has developed over the last two years – ranging from practical guides and CLI tools to full platforms – tailored for researchers, research software engineers (RSEs), and those involved in research infrastructure or policy. We warmly welcome constructive feedback and early adopters.

Intended audience
RSEs, researchers, all levels are welcomed

Main contributions
A list of tools and resources to be shown and ready-to-be-used to the audience.

Learning objectives
- What is a Research Software
- What is EVERSE and its contributions
- How to enhance my research software code quality through a guide I follow, or CLI/GitHub Actions
- How I can get credit for the software work I did

Speaker: Stefan Roiser (CERN)

20 Software sustainability in BESIII experiment

The BESIII experiment has been operating since 2009 and has received several upgrades, to study the tau-charm physics utilizing the BEPCII accelerator.Both the accelerator and BESIII detector has been upgraded during these years. The BESIII offline software system is developed based on Gaudi framework, provides the fundamental basis for physics analysis.This talk will focus on the development and sustainability in BESIII offline software, explaining how it meets requirements during the long life time of BESIII, various upgrades to be compatible with the new accelerator, new detector, new operating system and external libraries.

Speaker: Dr Ziyan Deng

WLCG: DC27

Conveners: Johannes Elmsheuser (Brookhaven National Laboratory (US)), Katy Ellis (Science and Technology Facilities Council STFC (GB))

21 FTS in DC27

Speaker: Steven Murray (CERN)

22 Monitoring and DC27 dashboard

Speaker: Borja Garrido Bear (CERN)

23 XRootD monitoring

Speaker: Panos Paparrigopoulos (CERN)

24 Agentic AI support (TBC)

Speaker: Dmytro Kovalskyi (Massachusetts Inst. of Technology (US))

12:30 Lunch

Plenary Session: Heterogenous SW and HW

Conveners: Stefan Roiser (CERN), Stefano Piano (INFN (IT))

25 intro and goal of the sessions

Speaker: Stefano Piano (INFN (IT))

26 Monte Carlo Event Generation

Speaker: Daniele Massaro (CERN)

27 Detector Simulation

Speaker: Severin Diederichs (CERN)

28 Root

Speaker: Danilo Piparo (CERN)

15:30 Tea Break

Plenary Session: Heterogeneous HW and SW

Conveners: Stefan Roiser (CERN), Stefano Piano (INFN (IT))

Wednesday 4 November

HSF: IRIS-HEP + EVERSE + SSI

Conveners: Caterina Doglioni (The University of Manchester (GB)), Elizabeth Sexton-Kennedy (Fermi National Accelerator Lab. (US))

WLCG: TAPE OTF

Conveners: Johannes Elmsheuser (Brookhaven National Laboratory (US)), Katy Ellis (Science and Technology Facilities Council STFC (GB)), Michael Davis (CERN)

29 Introduction

Speaker: Michael Davis (CERN)

30 Experiment Plans for DC27 and Run-4

Speaker: Christoph Wissing (Deutsches Elektronen-Synchrotron (DE))

31 Updates from WLCG Sites

Speaker: Julien Leduc (CERN)

10:30 Coffee Break

HSF: IRIS-HEP + EVERSE + SSI

Conveners: Caterina Doglioni (The University of Manchester (GB)), Elizabeth Sexton-Kennedy (Fermi National Accelerator Lab. (US))

WLCG: Tape OTF

Conveners: Johannes Elmsheuser (Brookhaven National Laboratory (US)), Katy Ellis (Science and Technology Facilities Council STFC (GB)), Michael Davis (CERN)

32 Tokens for Tape

Speaker: Steven Murray (CERN)

33 CTA roadmap

Speaker: Michael Davis (CERN)

34 dCache roadmap

Speaker: Mr Tigran Mkrtchyan (DESY)

35 StoRM roadmap

Speaker: Francesco Giacomini (INFN CNAF)

36 DC27 discussion

12:30 Lunch

HSF: Parallel HSF: BoF on affiliation programme + future

Convener: Eduardo Rodrigues (University of Liverpool (GB))

WLCG: Hepix Sites

Convener: Jose Flix Molina (CIEMAT - Centro de Investigaciones Energéticas Medioambientales y Tec. (ES))

37 WLCG Technical RoadMap Chapter 2 “Facility Evolution” status

Speaker: Jose Flix Molina (CIEMAT - Centro de Investigaciones Energéticas Medioambientales y Tec. (ES))

38 Update on Storage Capacity vs Throughput

39 News from HEPiX & Operational Effort at sites

Speaker: Ofer Rind (Brookhaven National Laboratory)

WLCG CB: WLCG CB (Restricted)

Conveners: Achim Streit (Unknown), Xavier Espinal (CERN)

15:30 Tea Break

Trip: Conference Trips

Thursday 5 November

HSF: Software Training in the AI-Assisted Coding Era

Conveners: Alexander Moreno Briceño (Universidad Antonio Nariño), Stefan Roiser (CERN)

WLCG: Operations

Conveners: Julia Andreeva (CERN), Maarten Litmaath (CERN), Panos Paparrigopoulos (CERN)

40 Operations @ CNAF

41 Accounting: PEAR

Speaker: Alastair Dewhurst (Science and Technology Facilities Council STFC (GB))

42 Accounting: AUDITOR

Speaker: Michael Boehler (University of Freiburg (DE))

10:30 Coffee Break

HSF: Software Training in the AI-Assisted Coding Era

Conveners: Alexander Moreno Briceño (Universidad Antonio Nariño), Stefan Roiser (CERN)

WLCG: Operations

Conveners: Julia Andreeva (CERN), Maarten Litmaath (CERN), Panos Paparrigopoulos (CERN)

43 Update from WLCG Security

Speaker: Jose Carlos Luna Duran (CERN)

44 Tokens Evolution

Speaker: Maarten Litmaath (CERN)

45 GRID Middleware - State of afairs

Speaker: Maarten Litmaath (CERN)

46 Update from the IPv6 Working Group

Speaker: Dr Andrea Sciabà (CERN)

12:30 Lunch

Plenary Session: DC27 + Tape OTF

Conveners: Johannes Elmsheuser (Brookhaven National Laboratory (US)), Katy Ellis (Science and Technology Facilities Council STFC (GB)), Michael Davis (CERN)

47 Summary DC27 session

Speakers: Johannes Elmsheuser (Brookhaven National Laboratory (US)), Katy Ellis (Science and Technology Facilities Council STFC (GB))

48 Discussion

49 Summary of Tape session

Speaker: Michael Davis (CERN)

50 Discussion

HSF Advisory Group meeting (Restricted)

HSF Advisory Group meeting (Restricted)

Conveners: Dr Chris Gutschow (UCL), Eduardo Rodrigues (University of Liverpool (GB))

15:30 Tea Break

Plenary Session: AI (operations + coding assistants)

Conveners: Alessandro Di Girolamo (CERN), Claire Antel (CERN), Michel Hernandez Villanueva (Brookhaven National Laboratory (US)), Panos Paparrigopoulos (CERN), Tobias Fitschen (The University of Manchester (GB))

51 AI on Operations - Introduction

Speakers: Alessandro Di Girolamo (CERN), Panos Paparrigopoulos (CERN)

52 AI for WLCG operations, landscape and gaps

Speaker: Ilija Vukotic (University of Chicago (US))

53 ALICE Input - TItle TBD

Speaker: Maksim Melnik Storetvedt (Western Norway University of Applied Sciences (NO))

54 Building and Evaluating AI Assistance for CMS Computing Operations

Speaker: Hasan Ozturk (CERN)

55 AI-assisted site triage for CMS Site Support

Speaker: Giuseppe Bagliesi (Universita & INFN Pisa (IT))

56 An Observability Catalog and MCP Server for AI-Assisted Tier-1 Monitoring

Speaker: Simone Rossi Tisbeni (INFN - National Institute for Nuclear Physics)

57 Discussion

Speakers: Alessandro Di Girolamo (CERN), Panos Paparrigopoulos (CERN)

58 AI-assisted coding agents discussion

Interactive session with feedback on draft guidelines

Speaker: Claire Antel (CERN)

Friday 6 November

Plenary Session: AI (operations + coding assistants)

Conveners: Alessandro Di Girolamo (CERN), Claire Antel (CERN), Michel Hernandez Villanueva (Brookhaven National Laboratory (US)), Panos Paparrigopoulos (CERN), Tobias Fitschen (The University of Manchester (GB))

Plenary Session: Sustainability

Convener: Dr Tommaso Boccali (INFN Sezione di Pisa)

59 Sustainability

Speaker: Alastair Dewhurst (Science and Technology Facilities Council STFC (GB))

10:30 Coffee Break

Plenary Session: Reports from Operations and HSF Common Initiatives

Conveners: Eduardo Rodrigues (University of Liverpool (GB)), Julia Andreeva (CERN), Maarten Litmaath (CERN), Panos Paparrigopoulos (CERN), Stefan Roiser (CERN)

12:30 Light Lunch before leaving