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

INSPIRE JSON PDGID:

${{\mathit \chi}_{{{c1}}}{(1P)}}$

$I^G(J^{PC})$ = $0^+(1^{+ +})$

See the Review on ``Branching Ratios of ${{\mathit \psi}{(2S)}}$, ${{\mathit \chi}}_{c0,1,2}$ and ${{\mathit \eta}_{{{c}}}{(1S)}}$'' before the ${{\mathit \chi}_{{{c0}}}{(1P)}}$ Listings.

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${{\mathit \chi}_{{{c1}}}{(1P)}}$ MASS

$3510.67$ $\pm0.05$ MeV (S = 1.2)

${{\mathit \chi}_{{{c1}}}{(1P)}}$ WIDTH

$0.84$ $\pm0.04$ MeV (S = 1.1)

▸ MULTIPOLE AMPLITUDES IN ${{\mathit \chi}_{{{c1}}}{(1P)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$

▸ MULTIPOLE AMPLITUDES IN ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{{c1}}}{(1S)}}$ RADIATIVE DECAY

▸ MULTIPOLE AMPLITUDE RATIOS IN RADIATIVE DECAYS ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{{c1}}}{(1S)}}$ and ${{\mathit \chi}_{{{c1}}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$

${{\mathit \chi}_{{{c1}}}{(1P)}}$ DECAY MODES

Mode

Fraction ($\Gamma_i$ / $\Gamma$)

Scale Factor/
Conf. Level

P(MeV/c)

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

($1.4^{+1.5}_{-1.0}$) $ \times 10^{-7}$

▸ Hadronic decays

▸ Radiative decays

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 (Japan), INFN (Italy) and CERN. Individual collaborators receive support for their PDG activities from their respective institutes or funding agencies. © 2025. See LBNL disclaimers.