Institute of High Energy Physics (IHEP) — JUNO

Focus

Host institution of the Jiangmen Underground Neutrino Observatory, plus broad experimental particle-physics program at the Beijing Electron-Positron Collider (BEPC) and related facilities.

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Institutional context

IHEP was founded in 1973 as China’s primary high-energy physics laboratory, following the country’s decision to enter the international particle-physics community. The institute operates the Beijing Electron-Positron Collider, the Beijing Spectrometer, and the China Spallation Neutron Source, in addition to its neutrino-physics program.

The neutrino program has been a strategic priority since the late 1990s. IHEP led the Daya Bay reactor experiment (2011–2020) that measured ${\theta }_{13}$ and then initiated the JUNO project that succeeded it.

JUNO facility

The Jiangmen Underground Neutrino Observatory (see the JUNO experiment page) sits 700 m underground near the town of Kaiping in Guangdong province, at a 53 km baseline from the Yangjiang and Taishan reactor complexes. The 20 kt liquid-scintillator detector, commissioned in 2024 with first oscillation data in 2025, is the largest ever built.

The associated TAO (Taishan Antineutrino Observatory) detector at 30 m from one reactor complex provides the near-site reference spectrum for JUNO’s mass-ordering analysis.

Broader neutrino program

IHEP also contributes to:

• Hyper-Kamiokande (Japan) as a collaborating institution
• The proposed CEPC (Circular Electron-Positron Collider)
• Space-based cosmic-ray and gamma-ray missions (HXMT, DAMPE)

Significance

JUNO will provide the first mass-ordering determination through vacuum-oscillation spectroscopy, independent of the matter-effect approach pursued by DUNE. Combined with the precision $\Delta m_{21}^2$ and ${\theta }_{12}$ measurements JUNO will deliver, IHEP’s neutrino program positions China as one of the three principal global centers for the field alongside Japan and the United States.