Abstract
We performed a search for a new generic boson, which could be a scalar (), pseudoscalar (), vector (), or an axial vector () particle produced in the 100 GeV electron scattering off nuclei, , followed by its invisible decay in the NA64 experiment at CERN. No evidence for such a process was found in the full NA64 dataset of electrons on target. We place new bounds on the , , , coupling strengths to electrons, and set constraints on their contributions to the electron anomalous magnetic moment , for the mass region . These results are an order of magnitude more sensitive compared to the current accuracy on from the electron experiments and recent high-precision determination of the fine structure constant.
- Received 6 February 2021
- Accepted 16 April 2021
DOI:https://doi.org/10.1103/PhysRevLett.126.211802
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society