Limits for Excited ${{\boldsymbol e}}$ (${{\boldsymbol e}^{*}}$) from Pair Production
INSPIRE search
These limits are obtained from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{*+}}{{\mathit e}^{*-}}$ and thus rely only on the (electroweak) charge of ${{\mathit e}^{*}}$. Form factor effects are ignored unless noted. For the case of limits from ${{\mathit Z}}$ decay, the ${{\mathit e}^{*}}$ coupling is assumed to be of sequential type. Possible ${{\mathit t}}~$channel contribution from transition magnetic coupling is neglected. All limits assume a dominant ${{\mathit e}^{*}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \gamma}}$ decay except the limits from $\Gamma\mathrm {({{\mathit Z}})}$.
For limits prior to 1987, see our 1992 edition (Physical Review D45 S1 (1992)).
