${{\overline{\mathit p}}}/{{\mathit p}}$ CHARGE-TO-MASS RATIO, $\vert {\mathit q_{{{\overline{\mathit p}}}}\over {\mathit m}_{{{\overline{\mathit p}}}}}\vert /({\mathit q_{{{\mathit p}}}\over {\mathit m}_{{{\mathit p}}}}$)

INSPIRE search
A test of $\mathit CPT$ invariance. Listed here are measurements involving the $\mathit inertial$ masses. For a discussion of what may be inferred about the ratio of ${{\overline{\mathit p}}}$ and ${{\mathit p}}$ $\mathit gravitational$ masses, see ERICSON 1990 ; they obtain an upper bound of $10^{-6}-10^{-7}$ for violation of the equivalence principle for ${{\overline{\mathit p}}}$'s.
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ 1.000000000003 \pm0.000000000016}$ OUR AVERAGE
$1.000000000003$ $\pm0.000000000016$
BORCHERT
2022
TRAP Penning trap
$1.000000000001$ $\pm0.000000000069$
ULMER
2015
TRAP Penning trap
• • We do not use the following data for averages, fits, limits, etc. • •
$0.99999999991$ $\pm0.00000000009$
GABRIELSE
1999
TRAP Penning trap
$1.0000000015$ $\pm0.0000000011$ 1
GABRIELSE
1995
TRAP Penning trap
$1.000000023$ $\pm0.000000042$ 2
GABRIELSE
1990
TRAP Penning trap
1  Equation (2) of GABRIELSE 1995 should read $\mathit M({{\overline{\mathit p}}})/\mathit M({{\mathit p}}$) = $0.999~999~995~$(11) (G.$~$Gabrielse, private communication).
2  GABRIELSE 1990 also measures ${\mathit m}_{{{\overline{\mathit p}}}}/{\mathit m}_{{{\mathit e}^{-}}}$ = $1836.152660$ $\pm0.000083$ and ${\mathit m}_{{{\mathit p}}}/{\mathit m}_{{{\mathit e}^{-}}}$ = $1836.152680$ $\pm0.000088$. Both are completely consistent with the 1986 CODATA (COHEN 1987 ) value for ${\mathit m}_{{{\mathit p}}}/{\mathit m}_{{{\mathit e}^{-}}}$ of $1836.152701$ $\pm0.000037$.
References:
BORCHERT 2022
NAT 601 53
ULMER 2015
NAT 524 196 High-Precision Comparison of the Antiproton-to-Proton Charge-to-Mass Ratio
GABRIELSE 1999
PRL 82 3198 Precision Mass Spectroscopy of the Antiproton and Proton Using Simultaneously Trapped Particles
GABRIELSE 1995
PRL 74 3544 Special Relativity and the Single Antiproton: Fortyfold Improved Comparison of ${{\overline{\mathit p}}}$ and ${{\mathit p}}$ Charge-to-Mass Ratios
GABRIELSE 1990
PRL 65 1317 A 1000 $−$ Fold Improvement in the Measured Antiproton Mass