The Dalitz-decay contributions of ${\pi }^0$ and η mesons to the di-electron invariant-mass spectrum at 1$A$ GeV have been obtained from a systematics of inclusive meson production cross sections measured for the collision systems ${}^{12}\mathrm{C}{+}^{\mathrm{nat}}\mathrm{C}$ and ${}^{40}\mathrm{Ar},{}^{40}\mathrm{Ca}{+}^{\mathrm{nat}}\mathrm{Ca}$ in the bombarding-energy range of 0.8–2.0 $A$ GeV. These results are compared with the recently published di-electron mass spectra of the DLS collaboration. Systematic errors and angular-distribution effects are discussed. We conclude that the low-mass part of the DLS data cannot be explained by the Dalitz decays of light neutral mesons only.

• Received 9 September 1997

DOI:https://doi.org/10.1103/PhysRevC.56.R2920