# Limits for Excited ${{\boldsymbol e}}$ (${{\boldsymbol e}^{*}}$) from ${{\boldsymbol e}^{+}}$ ${{\boldsymbol e}^{-}}$ $\rightarrow$ ${{\boldsymbol \gamma}}{{\boldsymbol \gamma}}$ INSPIRE search

These limits are derived from indirect effects due to ${{\mathit e}^{*}}$ exchange in the ${{\mathit t}}~$channel and depend on transition magnetic coupling between ${{\mathit e}}$ and ${{\mathit e}^{*}}$. All limits are for ${{\mathit \lambda}_{{\gamma}}}$ = 1. All limits except ABE 1989J and ACHARD 2002D are for nonchiral coupling with ${{\mathit \eta}_{{L}}}$ = ${{\mathit \eta}_{{R}}}$ = 1. We choose the chiral coupling limit as the best limit and list it in the Summary Table.

For limits prior to 1987, see our 1992 edition (Physical Review D45 S1 (1992)).
VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$\bf{>356}$ 95 1
 2004 N
DLPH $\sqrt {s }$= $161 - 208~$GeV
• • • We do not use the following data for averages, fits, limits, etc. • • •
$>310$ 95
 2002 D
L3 $\sqrt {\mathit s }$= $192 - 209$ GeV
1  ABDALLAH 2004N also obtain a limit on the excited electron mass with ${{\mathit e}}{{\mathit e}^{*}}$ chiral coupling, ${\mathit m}_{{{\mathit e}^{*}}}>295$ GeV at 95$\%$ CL.
References:
 ABDALLAH 2004N
EPJ C37 405 Determination of the ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$( ${{\mathit \gamma}}$) Cross-Section at LEP 2
 ACHARD 2002D
PL B531 28 Study of Multiphoton Final States and Tests of QED in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ up to 209 GeV