pdgLive

2019

BES3

${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \omega}}{{\mathit \omega}}$

$30.8$ ${}^{+2.3}_{-2.2}$ $\pm2.9$

2673

2018

BELL

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit \eta}^{\,'}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$

$34.0$ $\pm1.9$ $\pm1.3$

11k

2017

LHCB

${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit B}^{+}}{{\mathit X}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}{{\mathit K}^{+}}{{\mathit X}}$

$31.4$ $\pm3.5$ $\pm2.0$

6.4k

2017

LHCB

${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit X}}$ $\rightarrow$ 2( ${{\mathit K}^{+}}{{\mathit K}^{-}}$) ${{\mathit X}}$

$27.2$ $\pm3.1$ ${}^{+5.4}_{-2.6}$

ANASHIN

KEDR

${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$

$25.2$ $\pm2.6$ $\pm2.4$

4.5k

³ ^{, 4}

BABR

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

$34.8$ $\pm3.1$ $\pm4.0$

900

³ ^{, 5}^{, 4}

BABR

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

$32.0$ $\pm1.2$ $\pm1.0$

⁶ ^{, 7}

2012

BES3

${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$

$36.4$ $\pm3.2$ $\pm1.7$

832

2012

BES3

${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \gamma}}$ hadrons

$37.8$ ${}^{+5.8}_{-5.3}$ $\pm3.1$

486

ZHANG

2012

BELL

${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit \eta}^{\,'}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$

$36.2$ $\pm2.8$ $\pm3.0$

11k

DEL-AMO-SANCH..

BABR

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

$35.1$ $\pm3.1$ ${}^{+1.0}_{-1.6}$

920

⁷

VINOKUROVA

BELL

${{\mathit B}^{\pm}}$ $\rightarrow$ ${{\mathit K}^{\pm}}$ ( ${{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$ )

$31.7$ $\pm1.2$ $\pm0.8$

14k

⁸

2010

BABR

10.6 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$

$36.3$ ${}^{+3.7}_{-3.6}$ $\pm4.4$

0.9k

2008

BABR

${{\mathit B}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}{(1S)}}{{\mathit K}^{(*)}}$ $\rightarrow$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}{{\mathit K}^{(*)}}$

$28.1$ $\pm3.2$ $\pm2.2$

7.5k

UEHARA

2008

BELL

${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}}$ $\rightarrow$ hadrons

$48$ ${}^{+8}_{-7}$ $\pm5$

195

2006

BELL

${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}{{\mathit K}^{+}}$

$40$ $\pm19$ $\pm5$

2006

BELL

${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\overline{\mathit \Lambda}}}{{\mathit K}^{+}}$

$24.8$ $\pm3.4$ $\pm3.5$

592

ASNER

2004

CLEO

${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}^{\,'}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$

$20.4$ ${}^{+7.7}_{-6.7}$ $\pm2.0$

190

AMBROGIANI

E835

${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$

$23.9$ ${}^{+12.6}_{-7.1}$

ARMSTRONG

1995

E760

${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$

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

$32.1$ $\pm1.1$ $\pm1.3$

12k

⁹

DEL-AMO-SANCH..

BABR

${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$

$34.3$ $\pm2.3$ $\pm0.9$

2.5k

¹⁰

2004

BABR

${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$

$17.0$ $\pm3.7$ $\pm7.4$

¹¹

BES

${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$

$29$ $\pm8$ $\pm6$

180

¹²

FANG

BELL

${{\mathit B}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}}{{\mathit K}}$

$11.0$ $\pm8.1$ $\pm4.1$

¹³

2000

BES

${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$ and ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$

$27.0$ $\pm5.8$ $\pm1.4$

¹⁴

BRANDENBURG

2000

CLE2

${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}}$ $\rightarrow$ ${{\mathit K}^{\pm}}{{\mathit K}_S^0}$ ${{\mathit \pi}^{\mp}}$

$7.0$ ${}^{+7.5}_{-7.0}$

BAGLIN

1987

SPEC

${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$

$10.1$ ${}^{+33.0}_{-8.2}$

¹⁵

BALTRUSAITIS

MRK3

${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit p}}{{\overline{\mathit p}}}$

$11.5$ $\pm4.5$

GAISER

CBAL

${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}$ X, ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}$ X

$< 40 90\% CL$

HIMEL

1980

MRK2

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

$< 20 90\% CL$

PARTRIDGE

1980

CBAL

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

¹	From a fit of the ${{\mathit \phi}}{{\mathit \phi}}$ invariant mass with the mass and width of ${{\mathit \eta}_{{c}}{(1S)}}$ as free parameters.

²	Taking into account an asymmetric photon lineshape.

³	With floating mass.

⁴	Ignoring possible interference with the non-resonant 0${}^{-}$ amplitude.

⁵	Using both, ${{\mathit \eta}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ and ${{\mathit \eta}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ decays.

⁶	From a simultaneous fit to six decay modes of the ${{\mathit \eta}_{{c}}}$.

⁷	Accounts for interference with non-resonant continuum.

⁸	Taking into account interference with the non-resonant $\mathit J{}^{P} = 0-$ amplitude.

⁹	Not independent from the measurements reported by LEES 2010 .

¹⁰	Superseded by LEES 2010 .

¹¹	From a simultaneous fit of five decay modes of the ${{\mathit \eta}_{{c}}}$.

¹²	Superseded by VINOKUROVA 2011 .

¹³	From a fit to the 4-prong invariant mass in ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$ and ${{\mathit J / \psi}{(1S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$ decays.

¹⁴	Superseded by ASNER 2004 .

¹⁵	Positive and negative errors correspond to 90$\%$ confidence level.

References:

2019AV

PR D100 052012

Observation of $\eta_c\to\omega\omega$ in $J/\psi\to\gamma\omega\omega$

2018

PR D98 072001

Measurement of eta_c(1S), eta_c(2S) and non-resonant eta' pi+ pi- production via two-photon collisions

2017AD

PL B769 305

Observation of ${{\mathit \eta}_{{c}}{(2S)}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}$ and Search for ${{\mathit X}{(3872)}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}$ Decays

2017BB

EPJ C77 609

Study of Charmonium Production in hadron Decays and First Evidence for the Decay ${{\mathit B}_{{s}}^{0}}$ $\rightarrow$ ${{\mathit \phi}}{{\mathit \phi}}{{\mathit \phi}}$

ANASHIN

PL B738 391

Measurement of ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$ Decay Rate and ${{\mathit \eta}_{{c}}}$ Parameters at KEDR

2014E

PR D89 112004

Dalitz Plot Analysis of ${{\mathit \eta}_{{c}}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \eta}}$ and ${{\mathit \eta}_{{c}}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{0}}$ in Two-Photon Interactions

2012N

PR D86 092009

Study of ${{\mathit \psi}{(3686)}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit h}_{{c}}}$ , ${{\mathit h}_{{c}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$ via ${{\mathit \eta}_{{c}}}$ Exclusive Decays

2012F

PRL 108 222002

Measurements of the Mass and Width of the ${{\mathit \eta}_{{c}}}$ Using the Decay ${{\mathit \psi}{(3686)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$

ZHANG

2012A

PR D86 052002

First Study of ${{\mathit \eta}_{{c}}{(1S)}}$, ${{\mathit \eta}{(1760)}}$ and ${{\mathit X}{(1835)}}$ Production via ${{\mathit \eta}^{\,'}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Final States in Two-Photon Collisions

DEL-AMO-SANCHEZ

2011M

PR D84 012004

Observation of ${{\mathit \eta}_{{c}}{(1S)}}$ and ${{\mathit \eta}_{{c}}{(2S)}}$ decays to ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ in Two-Photon Interactions

VINOKUROVA

PL B706 139

Study of ${{\mathit B}^{\pm}}$ $\rightarrow$ ${{\mathit K}^{\pm}}$ ($\mathit KSK{{\mathit \pi}}$) Decay and Determination of ${{\mathit \eta}_{{c}}}$ and ${{\mathit \eta}_{{c}}{(2S)}}$ Parameters

2010

PR D81 052010

Measurement of the ${{\mathit \gamma}}$ ${{\mathit \gamma}^{*}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}}$ Transition Form Factor

2008AB

PR D78 012006

Study of ${{\mathit B}}$-Meson Decays to ${{\mathit \eta}_{{c}}}{{\mathit K}^{(*)}}$ , ${{\mathit \eta}_{{c}}{(2S)}}{{\mathit K}^{(*)}}$ , and ${{\mathit \eta}_{{c}}}{{\mathit \gamma}}{{\mathit K}^{(*)}}$

UEHARA

2008

EPJ C53 1

Study of Charmonia in Four-Meson Final States Produced in Two-Photon Collisions

2006

PRL 97 162003

Study of ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}$ , ${{\mathit \Lambda}}{{\overline{\mathit \Lambda}}}$ and Observation of ${{\mathit \eta}_{{c}}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\overline{\mathit \Lambda}}}$ at Belle

ASNER

2004

PRL 92 142001

Observation of ${{\mathit \eta}_{{c}}^{\,'}}$ Production in ${{\mathit \gamma}}{{\mathit \gamma}}$ Fusion at CLEO

2004D

PRL 92 142002

Measurements of the Mass and Width of the ${{\mathit \eta}_{{c}}}$ Meson and of an ${{\mathit \eta}_{{c}}{(2S)}}$ Candidate

AMBROGIANI

PL B566 45

Measurement of the Resonance Parameters of the Charmonium Ground State, ${{\mathit \eta}_{{c}}}(1_{1}S_{0}$)

PL B555 174

Measurement of the Mass and Full Width of the ${{\mathit \eta}_{{c}}}$ Meson

FANG

PRL 90 071801

Measurement of Branching Fractions for ${{\mathit B}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}}{{\mathit K}}{}^{(*)}$ Decays

2000F

PR D62 072001

A Measurement of the Mass and Full Width of the ${{\mathit \eta}_{{c}}}$ Meson

BRANDENBURG

2000B

PRL 85 3095

Measurements of the Mass, Total Width and Two Photon Partial Width of the ${{\mathit \eta}_{{c}}}$ Meson

ARMSTRONG

1995F

PR D52 4839

Study of the ${{\mathit \eta}_{{c}}}(1{}^{1}{{\mathit S}_{{0}}}$) State of Charmonium Formed in ${{\overline{\mathit p}}}{{\mathit p}}$ Annihilations and a Search for the ${{\mathit \eta}_{{c}}}(2{}^{1}{{\mathit S}_{{0}}}$)

BAGLIN

1987B

PL B187 191

Direct Observation and Partial Width Measurement of ${{\mathit \gamma}}{{\mathit \gamma}}$ Decay of Charmonium States

BALTRUSAITIS

PR D33 629

Hadronic Decay of the ${{\mathit \eta}_{{c}}{(2980)}}$

GAISER