Constraints On New Physics In Electron G-2 From A Search For Invisible Decays Of A Scalar, Pseudoscalar, Vector, And Axial Vector

We performed a search for a new generic X boson, which could be a scalar (S), pseudoscalar (P), vector (V), or an axial vector (A) particle produced in the 100 GeV electron scattering off nuclei, e(-)Z -> e(-)ZX, 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 2.84 x 10(11) electrons on target. We place new bounds on the S, P, V, A coupling strengths to electrons, and set constraints on their contributions to the electron anomalous magnetic moment a(e), vertical bar Delta aX vertical bar less than or similar to 10-15-10(-13) for the X mass region 1 MeV less than or similar to m(X) less than or similar to 1 GeV. These results are an order of magnitude more sensitive compared to the current accuracy on a(e) from the electron g - 2 experiments and recent high-precision determination of the fine structure constant.