https://doi.org/10.1140/epjs/s11734-026-02314-x
Regular Article
Precision measurement of the WW fusion cross section at 
GeV at the CEPC
1
Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
2
School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
3
Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
a
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b
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Received:
28
January
2026
Accepted:
10
April
2026
Published online:
27
April
2026
Abstract
The Circular Electron Positron Collider (CEPC) is proposed as a high-precision Higgs factory. As part of the global effort to evaluate the physics potential of future colliders, we present a comprehensive study of the WW fusion process (
) at a center-of-mass energy of GeV with an integrated luminosity of 1 ab
. Going beyond the extrapolations and fast simulations characteristic of previous studies, this work leverages the official CEPC software stack and full detector simulations. This approach ensures a rigorous accounting of reconstruction effects, background compositions, and quantum interference. Utilizing a two-dimensional template fit, we determine the signal cross-section with a statistical uncertainty of 1.00% and a total systematic uncertainty of 0.50%, achieving a total relative precision of 1.12% at 360 GeV. Combining this result with the projected precision from the 240 GeV run (1.59%), the global precision of the WW fusion cross-section improves to 0.92%. This sub-percent precision enables a model-independent determination of the Higgs total width 
with a relative uncertainty of approximately 1.19%, thereby demonstrating the critical role of the 360 GeV operation in the CEPC physics program.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
