${{\overline{\boldsymbol p}}}$ 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. • • •

$> 5.0$

SELLNER

2017

TRAP

Penning trap

$>8 \times 10^{5}$

GEER

2000

${{\overline{\mathit p}}}/{{\mathit p}}$ ratio, cosmic rays

$>0.28$

GABRIELSE

1990

TRAP

Penning trap

$>0.08$

BELL

1979

CNTR

Storage ring

$>1 \times 10^{7}$

GOLDEN

1979

SPEC

${{\overline{\mathit p}}}/{{\mathit p}}$ ratio, cosmic rays

$>3.7 \times 10^{-3}$

BREGMAN

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