#### Production of New Penetrating Non-${{\mathit \nu}}$ Like States in Beam Dump

VALUE DOCUMENT ID TECN  COMMENT
• • We do not use the following data for averages, fits, limits, etc. • •
1
 2021
NA64 search for new boson ${{\mathit X}}$ in ${{\mathit e}}$ ${{\mathit Z}}$ $\rightarrow$ ${{\mathit e}}{{\mathit Z}}{{\mathit X}}$
2
 1981
CALO 28 GeV protons
 1 ANDREEV 2021 search for new invisibly decaying boson ${{\mathit X}}$ in ${{\mathit e}}$ ${{\mathit Z}}$ $\rightarrow$ ${{\mathit e}}{{\mathit Z}}{{\mathit X}}$ at NA64. No signal observed. Limits set in coupling vs. m(X) plane for m(X) $\sim{}$ $10^{-3}$ to 1 GeV.
 2 No excess neutral-current events leads to ${\mathit \sigma (}$production${)}{\times }{\mathit \sigma (}$interaction${)}{\times }$acceptance $<2.26 \times 10^{-71}$ cm${}^{4}$/nucleon${}^{2}$ (CL = 90$\%$) for light neutrals. Acceptance depends on models (0.1 to $4. \times 10^{-4}$).
References:
 ANDREEV 2021
PRL 126 211802 Constraints on New Physics in Electron $g-2$ from a Search for Invisible Decays of a Scalar, Pseudoscalar, Vector, and Axial Vector
 LOSECCO 1981
PL 102B 209 Limits on the Production of Neutral Penetrating States in a Beam Dump