#### ${{\mathit K}_L^0}$ MEAN LIFE

VALUE ($10^{-8}$ s) EVTS DOCUMENT ID TECN  COMMENT
 $\bf{ 5.116 \pm0.021}$ OUR FIT  Error includes scale factor of 1.1.
 $\bf{ 5.099 \pm0.021}$ OUR AVERAGE
$5.072$ $\pm0.011$ $\pm0.035$ 13M 1
 2006
KLOE $\sum_{i}$ B$_{i}$ = 1
$5.092$ $\pm0.017$ $\pm0.025$ 15M
 2005 C
KLOE
$5.154$ $\pm0.044$ 0.4M
 1972
CNTR
• • We do not use the following data for averages, fits, limits, etc. • •
$5.15$ $\pm0.14$
 1967
CNTR
1  AMBROSINO 2006 uses ${{\mathit \phi}}$ $\rightarrow$ ${{\mathit K}_{{L}}}{{\mathit K}_{{S}}}$ with ${{\mathit K}_{{L}}}$ tagged by ${{\mathit K}_{{S}}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ . The four major ${{\mathit K}_{{L}}}$ BR's are measured, the small remainder ( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ , ${{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ , ${{\mathit \gamma}}{{\mathit \gamma}}$ ) is taken from PDG 2004 . This KLOE ${{\mathit K}_{{L}}}$ lifetime is obtained by imposing $\sum_{i}$ B$_{i}$ = 1. The correlation matrix among the four measured ${{\mathit K}_{{L}}}$ BR's and this ${{\mathit K}_{{L}}}$ lifetime is
 ${{\mathit K}_{{{e3}}}}$ ${{\mathit K}}_{{{\mathit \mu}}3}$ 3${{\mathit \pi}^{0}}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ ${{\mathit \tau}}_{{{\mathit K}_{{L}}}}$
 ${{\mathit K}_{{{e3}}}}$ 1 $-0.25$ $-0.56$ $-0.07$ 0.25
 ${{\mathit K}}_{{{\mathit \mu}}3}$ 1 $-0.43$ $-0.20$ 0.33
 3${{\mathit \pi}^{0}}$ 1 $-0.39$ $-0.21$
 ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ 1 $-0.39$
 ${{\mathit \tau}}_{{{\mathit K}_{{L}}}}$ 1
These correlations are taken into account in our fit. The average of this KLOE mean life measurement and the independent KLOE measurement in AMBROSINO 2005C is ($5.084$ $\pm0.023$) $\times 10^{-8}$ s.
References:
 AMBROSINO 2006
PL B632 43 Measurements of the Absolute Branching Ratios for the Dominant ${{\mathit K}_L^0}$ Decays, the ${{\mathit K}_L^0}$ Lifetime, and $\vert \mathit V_{us}\vert$ with the KLOE Detector
 AMBROSINO 2005C
PL B626 15 Measurement of the ${{\mathit K}_L^0}$ Meson Lifetime with the KLOE Detector
 VOSBURGH 1972
PR D6 1834 Measurement of the ${{\mathit K}_L^0}$ Mean Life
 Also
PRL 26 866 Measurement of the ${{\mathit K}_L^0}$ Mean Life
 DEVLIN 1967
PRL 18 54 Measurement of the ${{\mathit K}_{{2}}^{0}}$ Mean Life
 Also
PR 169 1045 Measurements of Total Cross Sections for ${{\mathit K}_{{2}}^{0}}$ Mesons on Protons and Selected Nuclei from 168 to 343 ${\mathrm {MeV}}/\mathit c$ and Measurement of the ${{\mathit K}_{{2}}^{0}}$ Mean Life.
see fit info