Limits for Excited ${{\mathit e}}$ (${{\mathit e}^{*}}$) from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$

INSPIRE   PDGID:
S054EXG
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
ABDALLAH
2004N
 DLPH $\sqrt {s }$= $161 - 208~$GeV
• • We do not use the following data for averages, fits, limits, etc. • •
$>310$ 95
ACHARD
2002D
 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