Work

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

Year: 2025

Type: article

Abstract: We investigate the sensitivity of proposed circular electron positron collider (CEPC) and future circular collider in its electron–positron mode (FCC-ee) with a center-of-mass energy of 240 GeV to long-lived dark photons heavier than 2 GeV that are pair produced via the prompt decays of a light scalar mixed with the Standard-Model Higgs boson. We compute the production and decay rates of both the light scalar and the dark photon, and develop two search strategies targeting displaced vertices within the inner tracker of the main detectors. Using Monte Carlo simulations, we evaluate the signal acceptance and projected sensitivity for each strategy. Our results show that, for the scalar-Higgs mixing angle set at 10 − 2 just below the current upper limit, the proposed searches at CEPC and FCC-ee can probe a dark-photon kinetic-mixing parameter several orders of magnitude below existing bounds, for dark photons lighter than half the dark-scalar mass.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/xs4d-jfrs

Authors: Kingman Cheung, Fei-Tung Chung, Zeren Simon Wang

Institutions: Konkuk University, National Tsing Hua University, Hefei University of Technology

Language: English

Topic: Particle physics theoretical and experimental studies

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: National Science and Technology Council, National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities

Awards: G1125091589, G2606027145, Probing New Physics at Gravitational-Wave and Collider Experiments, and Astronomical Observations, G5893494417