TY - JOUR

T1 - Search for Sub-GeV Dark Particles in 휂→휋0+Invisible Decay

AU - BESIII Collaboration

AU - Ачасов, Михаил Николаевич

AU - Мучной, Николай Юрьевич

AU - Николаев, Иван Борисович

N1 - The BESIII Collaboration thanks the staff of BEPCII [58] and the IHEP computing center for their strong support, thanks to the helpful discussion with Brian Batell. This work is supported in part by National Key R&D Program of China under Contracts No. 2023YFA1606000 and No. 2023YFA1606704; National Natural Science Foundation of China (NSFC) under Contracts No. 125B2107, No. 11635010, No. 11935015, No. 11935016, No. 11935018, No. 12025502, No. 12035009, No. 12035013, 12061131003, No. 12192260, No. 12192261, No. 12192262, No. 12192263, No. 12192264, No. 12192265, No. 12221005, No. 12225509, No. 12235017, and No. 12361141819; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the Strategic Priority Research Program of Chinese Academy of Sciences under Contract No. XDA0480600; CAS under Contract No. YSBR-101; the 100 Talents Program of CAS; the Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; ERC under Contract No. 758462; the German Research Foundation DFG under Contract No. FOR5327; Istituto Nazionale di Fisica Nucleare, Italy; the Knut and Alice Wallenberg Foundation under Contracts No. 2021.0174 and No. 2021.0299; the Ministry of Development of Turkey under Contract No. DPT2006K-120470; the National Research Foundation of Korea under Contract No. NRF-2022R1A2C1092335; the National Science and Technology fund of Mongolia; Polish National Science Centre under Contract No. 2024/53/B/ST2/00975; STFC (United Kingdom); the Swedish Research Council under Contract No. 2019.04595; and the U.S. Department of Energy under Contract No. DE-FG02-05ER41374.

PY - 2026/7/16

Y1 - 2026/7/16

N2 - Using (10087±44)×106  퐽/휓 events collected with the BESIII detector at the BEPCII collider at the center-of-mass energy of √푠=3.097  GeV, we report the first search for 휂→휋0⁢푆→휋0⁢휒⁢¯휒 with 푆 denoting an on-shell dark scalar boson and 휒 an invisible dark matter particle. No significant signals are observed with 푆 mass ranging from 0 to 400  MeV/푐2. The upper limits on the branching fractions and the new physics coupling strengths between 푆 and quarks are set to be (1.8–5.5)×10−5 and (1.3–3.2)×10−5 at the 90% confidence level, respectively. The constraints on the dark-matter-nucleon scattering cross section is improved by approximately five orders of magnitude over previous dark-matter-nucleon scattering experiments, providing unique insights into sub-GeV dark matter.

AB - Using (10087±44)×106  퐽/휓 events collected with the BESIII detector at the BEPCII collider at the center-of-mass energy of √푠=3.097  GeV, we report the first search for 휂→휋0⁢푆→휋0⁢휒⁢¯휒 with 푆 denoting an on-shell dark scalar boson and 휒 an invisible dark matter particle. No significant signals are observed with 푆 mass ranging from 0 to 400  MeV/푐2. The upper limits on the branching fractions and the new physics coupling strengths between 푆 and quarks are set to be (1.8–5.5)×10−5 and (1.3–3.2)×10−5 at the 90% confidence level, respectively. The constraints on the dark-matter-nucleon scattering cross section is improved by approximately five orders of magnitude over previous dark-matter-nucleon scattering experiments, providing unique insights into sub-GeV dark matter.

KW - Invisible decays

KW - Light mesons

KW - Lepton colliders

UR - https://www.scopus.com/pages/publications/105045978935

U2 - 10.1103/lbj8-qqm6

DO - 10.1103/lbj8-qqm6

M3 - Article

VL - 137

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 3

M1 - 031804

ER -