# Search for ${{\boldsymbol X}^{0}}$ Resonance in ${{\boldsymbol Z}}$ $\rightarrow$ ${{\boldsymbol f}}{{\overline{\boldsymbol f}}}{{\boldsymbol X}^{0}}$ INSPIRE search

The limit is for B( ${{\mathit Z}}$ $\rightarrow$ ${{\mathit f}}{{\overline{\mathit f}}}{{\mathit X}^{0}}$ ) $\cdot{}$ B( ${{\mathit X}^{0}}$ $\rightarrow$ ${{\mathit F}}$ ) where ${{\mathit f}}$ is a fermion and ${{\mathit F}}$ is the specified final state. Spin$~$0 is assumed for ${{\mathit X}^{0}}$.
VALUE CL% DOCUMENT ID TECN  COMMENT
• • • We do not use the following data for averages, fits, limits, etc. • • •
1
 1996 T
DLPH $\mathit f={{\mathit e}},{{\mathit \mu}},{{\mathit \tau}}$; $\mathit F$= ${{\mathit \gamma}}{{\mathit \gamma}}$
$<3.7 \times 10^{-6}$ 95 2
 1996 T
DLPH $\mathit f={{\mathit \nu}}$; $\mathit F$= ${{\mathit \gamma}}{{\mathit \gamma}}$
3
 1996 T
DLPH $\mathit f={{\mathit q}}$; $\mathit F$= ${{\mathit \gamma}}{{\mathit \gamma}}$
$<6.8 \times 10^{-6}$ 95 2
 1993 E
OPAL ${{\mathit f}}={{\mathit e}},{{\mathit \mu}},{{\mathit \tau}}$; ${{\mathit F}}$= ${{\mathit \gamma}}{{\mathit \gamma}}$
$<5.5 \times 10^{-6}$ 95 2
 1993 E
OPAL ${{\mathit f}}={{\mathit q}}$; ${{\mathit F}}$= ${{\mathit \gamma}}{{\mathit \gamma}}$
$<3.1 \times 10^{-6}$ 95 2
 1993 E
OPAL ${{\mathit f}}={{\mathit \nu}}$; ${{\mathit F}}$= ${{\mathit \gamma}}{{\mathit \gamma}}$
$<6.5 \times 10^{-6}$ 95 2
 1993 E
OPAL ${{\mathit f}}={{\mathit e}},{{\mathit \mu}}$; ${{\mathit F}}$= ${{\mathit \ell}}{{\overline{\mathit \ell}}}$ , ${{\mathit q}}{{\overline{\mathit q}}}$ , ${{\mathit \nu}}{{\overline{\mathit \nu}}}$
$<7.1 \times 10^{-6}$ 95 2
 1993 F
ALEP ${{\mathit f}}={{\mathit e}},{{\mathit \mu}}$; ${{\mathit F}}$= ${{\mathit \ell}}{{\overline{\mathit \ell}}}$ , ${{\mathit q}}{{\overline{\mathit q}}}$ , ${{\mathit \nu}}{{\overline{\mathit \nu}}}$
4
 1992 F
L3 ${{\mathit f}}={{\mathit q}}$; ${{\mathit F}}$= ${{\mathit \gamma}}{{\mathit \gamma}}$
1  ABREU 1996T obtain limit as a function of ${\mathit m}_{{{\mathit X}^{0}}}$. See their Fig.$~$6.
2  Limit is for ${\mathit m}_{{{\mathit X}^{0}}}$ around 60 GeV.
3  ABREU 1996T obtain limit as a function of ${\mathit m}_{{{\mathit X}^{0}}}$. See their Fig.$~$15.
4  ADRIANI 1992F give ${{\mathit \sigma}_{{Z}}}\cdot{}$B( ${{\mathit Z}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}{{\mathit X}^{0}}$ ) $\cdot{}$ B( ${{\mathit X}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ )$<(0.75 - 1.5)~$pb (95$\%$CL) for ${\mathit m}_{{{\mathit X}^{0}}}$ = $10 - 70$ GeV. The limit is 1$~$pb at 60 GeV.
References:
 ABREU 1996T
ZPHY C72 179 Search for High Mass ${{\mathit \gamma}}{{\mathit \gamma}}$ Resonances in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\mathit \gamma}}{{\mathit \gamma}}$ , ${{\mathit \nu}}{{\overline{\mathit \nu}}}{{\mathit \gamma}}{{\mathit \gamma}}$ and ${{\mathit q}}{{\overline{\mathit q}}}{{\mathit \gamma}}{{\mathit \gamma}}$ at LEP I
 ACTON 1993E
PL B311 391 Search for Anomalous Production of High Mass Photon Pairs in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at LEP
 BUSKULIC 1993F
PL B308 425 Search for High Mass Photon Pairs in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit f}}{{\overline{\mathit f}}}{{\mathit \gamma}}{{\mathit \gamma}}$ (f = ${{\mathit e}^{-}}$, ${{\mathit \mu}}$, ${{\mathit \tau}}$, ${{\mathit \nu}}$, ${{\mathit q}}$) at LEP
PL B292 472 Isolated Hard Photon Emission in Hadronic ${{\mathit Z}^{0}}$ Decays