# ${{\overline{\boldsymbol p}}}$ MEAN LIFE INSPIRE search

Of the two astrophysical limits here, that of GEER 2000D involves considerably more refinements in its modeling. The other limits come from direct observations of stored antiprotons. See also ${{\overline{\mathit p}}}$ Partial Mean Lives'' after ${{\mathit p}}$ Partial Mean Lives,'' below, for exclusive-mode limits. The best (lifetime/branching fraction) limit there is $7 \times 10^{5}$ years, for ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit e}^{-}}{{\mathit \gamma}}$ . We advance only the exclusive-mode limits to our Summary Tables.
VALUE (years) CL% EVTS DOCUMENT ID TECN  COMMENT
• • • We do not use the following data for averages, fits, limits, etc. • • •
$> 5.0$ 90
 2017
TRAP Penning trap
$>8 \times 10^{5}$ 90 1
 2000 D
${{\overline{\mathit p}}}/{{\mathit p}}$ ratio, cosmic rays
$>0.28$
 1990
TRAP Penning trap
$>0.08$ 90 1
 1979
CNTR Storage ring
$>1 \times 10^{7}$
 1979
SPEC ${{\overline{\mathit p}}}/{{\mathit p}}$ ratio, cosmic rays
$>3.7 \times 10^{-3}$
 1978
CNTR Storage ring
1  GEER 2000D uses agreement between a model of galactic ${{\overline{\mathit p}}}~$production and propagation and the observed ${{\overline{\mathit p}}}/{{\mathit p}}$ cosmic-ray spectrum to set this limit.
References:
 SELLNER 2017
NJP 19 083023 Improved limit on the directly measured antiproton lifetime
 GEER 2000D
APJ 532 648 A New Limit on the ${{\overline{\mathit p}}}$ Lifetime
 GABRIELSE 1990
PRL 65 1317 A 1000 $−$ Fold Improvement in the Measured Antiproton Mass
 BELL 1979
PL 86B 215 Antiproton Lifetime Measurement in the ICE Storage Ring using Counter Technique
 GOLDEN 1979
PRL 43 1196 Evidence for the Existence of Cosmic Ray antiprotons
 BREGMAN 1978
PL 78B 174 Measurement of Antiproton Lifetime using the ICE Storage Ring