pdgLive

${\mathit {\mathit c}}$ ${\mathit {\overline{\mathit c}}}$ MESONS
(including possibly non-${\mathit {\mathit q}}$ ${\mathit {\overline{\mathit q}}}$ states)

INSPIRE JSON PDGID:

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

$I^G(J^{PC})$ = $0^+(0^{- +})$

Quantum numbers are quark model predictions.

${{\mathit \eta}_{{{c}}}{(2S)}}$ MASS

$3637.8 \pm0.6$ MeV (S = 1.1)

${{\mathit \eta}_{{{c}}}{(2S)}}$ WIDTH

$11.6 \pm1.4$ MeV

${{\mathit \eta}_{{{c}}}{(2S)}}$ DECAY MODES

${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$

$(1.9^{+1.2}_{-1.0})\%$

${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \eta}}$

$(7^{+5}_{-4})\times 10^{-3}$

${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \eta}^{\,'}}$

$(2.1\pm{1.6})\times 10^{-3}$

2 ${{\mathit \pi}^{+}}$2 ${{\mathit \pi}^{-}}$

$<2.6\times 10^{-3}$

${{\mathit a}_{{{0}}}{(1450)}}{{\mathit \pi}}$

${{\mathit a}_{{{2}}}{(1700)}}{{\mathit \pi}}$

${{\mathit a}_{{{0}}}{(1710)}}{{\mathit \pi}}$

${{\mathit \rho}^{0}}{{\mathit \rho}^{0}}$

$<2.3\times 10^{-3}$

3 ${{\mathit \pi}^{+}}$3 ${{\mathit \pi}^{-}}$

$(1.7^{+0.9}_{-1.1})\%$

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

$<2.5\times 10^{-3}$

${{\mathit K}^{*0}}{{\overline{\mathit K}}^{*0}}$

$<4\times 10^{-3}$

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

$(1.5^{+1.0}_{-0.9})\%$

${{\mathit K}^{+}}{{\mathit K}^{-}}$2 ${{\mathit \pi}^{+}}$2 ${{\mathit \pi}^{-}}$

${{\mathit K}_S^0}$ ${{\mathit K}^{-}}$2 ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ + c.c.

$(1.4^{+0.8}_{-1.0})\%$

2 ${{\mathit K}^{+}}$2 ${{\mathit K}^{-}}$

$<1.4\times 10^{-3}$

${{\mathit K}_{{{2}}}^{*}{(1430)}}{{\overline{\mathit K}}}$ + c.c.

${{\mathit K}_{{{0}}}^{*}{(1950)}}{{\overline{\mathit K}}}$ + c.c.

${{\mathit K}_{{{0}}}^{*}{(2600)}}{{\overline{\mathit K}}}$ + c.c.

${{\mathit \phi}}{{\mathit \phi}}$

$<1.4\times 10^{-3}$

${{\mathit \omega}}{{\mathit \omega}}$

$<1.9\times 10^{-3}$

${{\mathit \omega}}{{\mathit \phi}}$

$<3.4\times 10^{-4}$

${{\mathit p}}{{\overline{\mathit p}}}$

$<3.2\times 10^{-4}$

${{\mathit p}}{{\overline{\mathit p}}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$

${{\mathit p}}{{\overline{\mathit p}}}{{\mathit K}^{+}}{{\mathit K}^{-}}$

$(3.6\pm{2.9})\times 10^{-4}$

${{\mathit \gamma}}{{\mathit \gamma}}$

$(1.8^{+1.0}_{-1.1})\times 10^{-4}$

${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$

${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \eta}}$

$(5.5^{+3.3}_{-4.0})\times 10^{-3}$

2 ${{\mathit \pi}^{+}}$2 ${{\mathit \pi}^{-}}{{\mathit \eta}}$

$(1.6^{+0.9}_{-1.0})\%$

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

$(2.7^{+2.0}_{-1.8})\times 10^{-3}$

${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \eta}_{{{c}}}{(1S)}}$

FOOTNOTES

Constrained Fit information

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.