pdgLive

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$, ${{\mathit K}_{{{S}}}}{{\mathit K}_{{{L}}}}$, ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$

$1019.40$ $\pm0.04$ $\pm0.05$

23k

AKHMETSHIN

2001

CMD2

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \gamma}}$

$1019.36$ $\pm0.12$

⁷

ACHASOV

2000

SND

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \gamma}}$

$1019.38$ $\pm0.07$ $\pm0.08$

2200

⁸

AKHMETSHIN

1999

CMD2

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{}\geq{}2{{\mathit \gamma}}$

$1019.51$ $\pm0.07$ $\pm0.10$

11169

AKHMETSHIN

1998

CMD2

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$

$1019.5$ $\pm0.4$

BARBERIS

1998

OMEG

450 ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit p}}$2 ${{\mathit K}^{+}}$2 ${{\mathit K}^{-}}$

$1019.42$ $\pm0.06$

55600

AKHMETSHIN

1995

CMD2

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ hadrons

$1019.7$ $\pm0.3$

2012

DAVENPORT

1986

MPSF

400 ${{\mathit p}}$ ${}^{}\mathrm {A}$ $\rightarrow$ 4 ${{\mathit K}}$ X

$1019.7$ $\pm0.1$ $\pm0.1$

5079

ALBRECHT

1985

ARG

10 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$ X

$1019.3$ $\pm0.1$

1500

ARENTON

1982

AEMS

11.8 polar. ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit K}}{{\mathit K}}$

$1019.67$ $\pm0.17$

25080

⁹

PELLINEN

1982

RVUE

$1019.52$ $\pm0.13$

3681

BUKIN

1978

OLYA

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ hadrons

• • We do not use the following data for averages, fits, limits, etc. • •

$1019.0330$ $\pm0.0084$

¹⁰

DUBNICKA

2024

RVUE

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$ , ${{\mathit K}_S^0}$ ${{\mathit K}_L^0}$

$1019.761$ $\pm0.130$

34M

¹¹

IGNATOV

2024

CMD3

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$

$1018.4$ $\pm0.5$ $\pm0.1$

¹²

ALBRECHT

2020

CBAR

0.9 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{0}}$

$1019.21$ $\pm0.04$ $\pm0.03$

¹³

HOID

2020

RVUE

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \gamma}}$

$1019.54$ $\pm0.10$ $\pm0.51$

¹⁴

AAIJ

2019

LHCB

${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit D}^{\pm}}{{\mathit X}}$

$1019.20$ $\pm0.02$ $\pm0.01$

¹⁵

HOFERICHTER

2019

RVUE

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$

$1019.469$ $\pm0.061$

1.7M

KOZYREV

2018

CMD3

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$

$1019.457$ $\pm0.061$

610k

KOZYREV

2016

CMD3

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit K}_L^0}$

$1019.48$ $\pm0.01$

LEES

2013

BABR

${{\mathit D}^{+}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$

$1019.441$ $\pm0.008$ $\pm0.080$

542k

¹⁶

AKHMETSHIN

2008

CMD2

1.02 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$

$1019.63$ $\pm0.07$

12540

¹⁷

AUBERT,B

2005

BABR

${{\mathit D}^{0}}$ $\rightarrow$ ${{\overline{\mathit K}}^{0}}{{\mathit K}^{+}}{{\mathit K}^{-}}$

$1019.8$ $\pm0.7$

ARMSTRONG

1986

OMEG

85 ${{\mathit \pi}^{+}}$ /${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \pi}^{+}}$ /${{\mathit p}}$4 ${{\mathit K}}{{\mathit p}}$

$1020.1$ $\pm0.11$

5526

¹⁷

ATKINSON

1986

OMEG

20$-$70 ${{\mathit \gamma}}{{\mathit p}}$

$1019.7$ $\pm1.0$

BEBEK

1986

CLEO

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$

$1019.411$ $\pm0.008$

642k

¹⁸

DIJKSTRA

1986

SPEC

100$-$200 ${{\mathit \pi}^{\pm}}$, ${{\overline{\mathit p}}}$, ${{\mathit p}}$, ${{\mathit K}^{\pm}}$, on ${}^{}\mathrm {Be}$

$1020.9$ $\pm0.2$

¹⁷

FRAME

1986

OMEG

13 ${{\mathit K}^{+}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \phi}}{{\mathit K}^{+}}{{\mathit p}}$

$1021.0$ $\pm0.2$

¹⁷

ARMSTRONG

1983

OMEG

18.5 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit K}^{+}}{{\mathit \Lambda}}$

$1020.0$ $\pm0.5$

¹⁷

ARMSTRONG

1983

OMEG

18.5 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit K}^{+}}{{\mathit \Lambda}}$

$1019.7$ $\pm0.3$

¹⁷

BARATE

1983

GOLI

190 ${{\mathit \pi}^{-}}$ ${}^{}\mathrm {Be}$ $\rightarrow$ 2 ${{\mathit \mu}}$ X

$1019.8$ $\pm0.2$ $\pm0.5$

766

IVANOV

1981

OLYA

1$-$1.4 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$

$1019.4$ $\pm0.5$

337

COOPER

1978

HBC

0.7$-$0.8 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit K}_L^0}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$

$1020$ $\pm1$

383

¹⁷

BALDI

1977

CNTR

10 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \phi}}{{\mathit p}}$

$1018.9$ $\pm0.6$

800

COHEN

1977

ASPK

6 ${{\mathit \pi}^{\pm}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit N}}$

$1019.7$ $\pm0.5$

454

KALBFLEISCH

1976

HBC

2.18 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit K}}{{\overline{\mathit K}}}$

$1019.4$ $\pm0.8$

984

BESCH

1974

CNTR

2 ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit K}^{+}}{{\mathit K}^{-}}$

$1020.3$ $\pm0.4$

100

BALLAM

1973

HBC

2.8$-$9.3 ${{\mathit \gamma}}{{\mathit p}}$

$1019.4$ $\pm0.7$

BINNIE

1973

CNTR

${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \phi}}{{\mathit n}}$

$1019.6$ $\pm0.5$

120

¹⁹

AGUILAR-BENIT..

1972

HBC

3.9,4.6 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit K}^{+}}{{\mathit K}^{-}}$

$1019.9$ $\pm0.5$

100

¹⁹

AGUILAR-BENIT..

1972

HBC

3.9,4.6 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit p}}{{\mathit K}^{+}}{{\mathit K}^{-}}$

$1020.4$ $\pm0.5$

131

COLLEY

1972

HBC

10 ${{\mathit K}^{+}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit p}}{{\mathit \phi}}$

$1019.9$ $\pm0.3$

410

STOTTLEMYER

1971

HBC

2.9 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Sigma}}{{\mathit \Lambda}}$ ${{\mathit K}}{{\overline{\mathit K}}}$

From a fit of the cross section in the energy region 1.000 $<$ $\sqrt {s }$ $<$ 1.100 GeV using a vector meson dominance model with contribution from ${{\mathit \phi}{(1020)}}$, ${{\mathit \rho}{(770)}}$, ${{\mathit \omega}{(782)}}$ and higher vector resonances. The the first three points near the threshold are removed in the fit.

²	Average of KOZYREV 2016 and KOZYREV 2018 values taking into account the correlated uncertainties. Supersedes individual KOZYREV 2016 and KOZYREV 2018 results.

³	Using a vector meson dominance model with contribution from ${{\mathit \phi}{(1020)}}$ and higher mass excitations of ${{\mathit \rho}{(770)}}$, ${{\mathit \omega}{(782)}}$, and ${{\mathit \phi}{(1020)}}$.

⁴	Using a phenomenological model based on KUHN 1990 with a sum of Breit-Wigner resonances for ${{\mathit \rho}{(770)}}$, ${{\mathit \omega}{(782)}}$, ${{\mathit \phi}{(1020)}}$ and their higher mass excitations.

⁵	Update of AKHMETSHIN 1999D

⁶

From the combined fit assuming that the total ${{\mathit \phi}{(1020)}}$ production cross section is saturated by those of ${{\mathit K}^{+}}{{\mathit K}^{-}}$, ${{\mathit K}_{{{S}}}}{{\mathit K}_{{{L}}}}$, ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$, and ${{\mathit \eta}}{{\mathit \gamma}}$ decays modes and using ACHASOV 2000B for the ${{\mathit \eta}}{{\mathit \gamma}}$ decay mode.

⁷	Using a total width of $4.43$ $\pm0.05$ MeV. Systematic uncertainty included.

⁸	Using a total width of $4.43$ $\pm0.05$ MeV.

⁹	PELLINEN 1982 review includes AKERLOF 1977, DAUM 1981, BALDI 1977, AYRES 1974, DEGROOT 1974.

¹⁰	From the fit to data of CMD3, BABAR and BES3.

¹¹

From a fit of the pion form factor in the energy range 0.32 $<$ $\sqrt {s }$ $<$ 1.2 GeV using the GOUNARIS 1968 parametrization with the complex phase of the ${{\mathit \rho}}−{{\mathit \omega}}$ interference leaving ${{\mathit \rho}{(1450)}}$, ${{\mathit \rho}{(1700)}}$ resonances as free parameters of the fit. Systematic errors not estimated.

¹²	Width fixed at 4.2 MeV.

¹³	The values were extracted from a dispersively improved Breit-Wigner parameterization and do not include vacuum polarization. Inclusion of vacuum polarization gives $1019.457$ $\pm0.020$ MeV.

¹⁴	From the ${{\mathit D}^{\pm}}$ $\rightarrow$ ${{\mathit K}^{\pm}}{{\mathit K}^{+}}{{\mathit K}^{-}}$ Dalitz plot fit with the Triple-M amplitude in the multimeson model of AOUDE 2018.

¹⁵	The values were extracted from a dispersively improved Breit-Wigner parameterization and do not include vacuum polarization.

¹⁶	Strongly correlated with AKHMETSHIN 2004.

¹⁷	Systematic errors not evaluated.

¹⁸	Weighted and scaled average of 12 measurements of DIJKSTRA 1986.

¹⁹	Mass errors enlarged by us to $\Gamma /\sqrt {\mathit N }$; see the note with the ${{\mathit K}^{*}{(892)}}$ mass.

References

Except where otherwise noted, content of the 2025 Review of Particle Physics is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) license. The publication of the Review of Particle Physics is supported by US DOE, MEXT and KEK (Japan), INFN (Italy) and CERN. Individual collaborators receive support for their PDG activities from their respective institutes or funding agencies. © 2025. See LBNL disclaimers.

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