HALHF Project
The Hybrid Asymmetric Linear Higgs Factory Project - HALHF
Introduction & Latest News
Welcome to the Hybrid Asymmetric Linear Higgs Factory (HALHF) Collaboration page. HALHF is a novel concept to build a relatively cheap "Higgs Factory" with a luminosity comparable to the conventional International Linear Collider (ILC) and Compact Linear Collider (CLIC) proposals. The HALHF concept is based on a hybrid design in which positrons are accelerated to 31 GeV in a conventional linac, which also provides the drive beams for a plasma-wakefield arm that accelerates electrons to 500 GeV. The energies are selected to produce Higgs particles in conjunction with Z bosons. The HALHF Collaboration is dedicated to R&D to prepare a pre-conceptual design in the context of the European Lab Directors' Group ESPP Plasma Accelerators Working Group.
News 04/04/25
HALHF has submitted its contribution to the European Partice Physics Strategy Update 2026:
B. Foster, C.A. Lindstrøm, R. D'Arcy, , "HALHF: a hybrid, asymmetric, linear Higgs factory using plasma- and RF-based acceleration", Input to the European Strategy for Particle Physics - 2026 Update
Meetings
Previous Meetings
HALHF Collaboration Kick-off Meeting, DESY, Hamburg, Afternoon of 23.10.2023 (Password HALHF-DESY-2023)
HALHF Collaboration Physics & Detector Meeting, 19.12.2023, 12.30-14.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 18.12.2023, 16.00-18.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 29.01.2024, 16.00-18.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 04.02.2024, 16.00-18.00 CET
HALHF Workshop, Oslo, 04-05.4.2024
HALHF Collaboration Accelerator Task Force Meeting, 14.05.2024, 16.00-18.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 12.06.2024, 16.00-18.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 03.07.2024, 16.00-18.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 29.08.2024, 16.00-18.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 24.09.2024, 16.00-18.00 CET
HALHF Workshop, Erice, Sicily, 03-08.10.24
HALHF Collaboration Accelerator Task Force Meeting, 02.12.2024, 16.00-18.00 CET
HALHF Collaboration Accelerator Task Force Meeting, 15.01.2025, 16.00-18.00 CET
HALHF Workshop, DESY, Hamburg, Germany, 28-29.02.2025
Future Meetings
Publications
B. Foster, R. D'Arcy, C.A. Lindstrøm, "A hybrid, asymmetric, linear Higgs factory based on plasma-wakefield and radio-frequency acceleration", New J. Phys. 25 093037 (2023)
C.A. Lindstrøm, R. D'Arcy, B. Foster, "Status of and upgrade concepts for HALHF: the hybrid, asymmetric, linear Higgs factory", https://arxiv.org/abs/2312.04975
B. Foster et.al., "Proceedings of the Erice Workshop: A new baseline for the hybrid, asymmetric, linear Higgs factory HALHF", Open Physics (2025)
B. Foster, C.A. Lindstrøm, R. D'Arcy, , "HALHF: a hybrid, asymmetric, linear Higgs factory using plasma- and RF-based acceleration", Input to the European Strategy for Particle Physics - 2026 Update
Talks given
ALEGRO 2023, Hamburg, Germany, 23.03.2023:
A Hybrid Asymmetric Linear Higgs Factory (HALHF): B. Foster
LCWS 2023, SLAC, Stanford, CA, USA, 15.5.2023:
A hybrid, asymmetric, linear Higgs factory based on plasma-wakefield and radio-frequency acceleration: B. Foster
Community Report on Accelerators Roadmap, Frascati, Italy, 12.07.2023:
The HALHF Project: C.A. Lindstrøm
Implications for the future physics programme: B. Foster
EPS 2023, Hamburg, Germany, 23.08.2023:
The HALHF Project: B. Foster
Physics Performance and Detector Requirements at an Asymmetric Higgs Factory: A. Laudrain
EAAC 2023, Elba, Italy, 22.09.2023:
A Hybrid Asymmetric Linear Higgs Factory (HALHF): C.A. Lindstrøm
Readiness of electron plasma linacs for a collider application: E. Adli
CLIC Mini Week, CERN, 11 - 13.12.2023:
HALHF Plans: B. Foster
ALEGRO Workshop, Lisbon, 19 - 22.03.2024
Hybrid Asymmetric Linear Higgs Factory (HALHF): Updates and Upgrades: R. D'Arcy
CEPC European Workshop, Marseilles, 8 - 11.04.2024
Status of the HALHF Project: B. Foster
Laboratoire Leprince-Ringuet (LLR), Ecole Polytechnique, Paris
The HALHF Project: B. Foster
European Laboratory Directors Group Meeting, Brookhaven National Laboratory, NY, USA, 6 - 7.06.2024
Parameter Optimisation of HALHF and Near-Term Goals: ESPP Roadmap: R. D'Arcy & C.A. Lindstrøm
LCWS24 Tokyo University, Tokyo, Japan, 8 - 11.07.2024
HALHF Status: B. Foster
ICHEP24, Prague, Czech Republic, 18 - 24.07.2024
Status of HALHF - a concept for a hybrid asymmetric linear Higgs factory: B. Foster
Physics Performance and Detector Requirements at an Asymmetric Higgs Factory: A. Laudrain
CEPC Workshop, Hangzhou, China, 23 - 26.10.2024
Status of HALHF: B. Foster
ECFA, CERN, 14 -15.11.2024
Plasma Accelerators and the HALHF Concept: E. Adli
Cold Copper Accelerator Technologies and Applications, Duke University, NC, USA, 13-14.01.2025
HALHF: C.A. Lindstrøm
IAS Program on Fundamental Physics, Hong Kong, 14-17.01.2025
HALHF Status: B. Foster
PWFA linac Working Group Meeting - 10 TeV Collider Study, 19.02.2025
HALHF: Current Status, Optimisation and Considerations: R. D'Arcy
36th Future Colliders @ DESY meeting, 04.04.2025
HALHF: B. Foster
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