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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:

${{\mathit \chi}_{{{c1}}}{(3872)}}$

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

also known as ${{\mathit X}{(3872)}}$

This state shows properties different from a conventional ${{\mathit q}}{{\overline{\mathit q}}}$ state. A candidate for an exotic structure. See the review on non-${{\mathit q}}{{\overline{\mathit q}}}$ states. First observed by CHOI 2003 in ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}{(1S)}}$ decays as a narrow peak in the invariant mass distribution of the ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}{(1S)}}$ final state. Isovector hypothesis excluded by AUBERT 2005B and CHOI 2011. AAIJ 2013Q perform a full five-dimensional amplitude analysis of the angular correlations between the decay products in ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit \chi}_{{{c1}}}{(3872)}}{{\mathit K}^{+}}$ decays, where ${{\mathit \chi}_{{{c1}}}{(3872)}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$, which unambiguously gives the $\mathit J{}^{PC} = 1{}^{++}$ assignment under the assumption that the ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit J / \psi}}$ are in an ${\mathit S}{\mathrm -wave}$. AAIJ 2015AO extend this analysis with more data to limit ${\mathit D}{\mathrm -wave}$ contributions to $<$ 4$\%$ at 95$\%$ CL. See the review on ``Spectroscopy of Mesons Containing Two Heavy Quarks.''

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${{\mathit \chi}_{{{c1}}}{(3872)}}$ T-MATRIX POLE $\sqrt {\mathit s }$

${{\mathit \chi}_{{{c1}}}{(3872)}}$ MASS FROM ${{\mathit J / \psi}}{{\mathit X}}$ MODE

$3871.64$ $\pm0.06$ MeV

${{\mathit \chi}_{{{c1}}}{(3872)}}$ MASS FROM ${{\overline{\mathit D}}^{*0}}{{\mathit D}^{0}}$ MODE

${\mathit m}_{{{\mathit \chi}_{{{c1}}}{(3872)}}}-{\mathit m}_{{{\mathit J / \psi}}}$

$775$ $\pm4$ MeV

${\mathit m}_{{{\mathit \chi}_{{{c1}}}{(3872)}}}-{\mathit m}_{{{\mathit \psi}{(2S)}}}$

${{\mathit \chi}_{{{c1}}}{(3872)}}$ WIDTH

$1.19$ $\pm0.21$ MeV (S = 1.1)

${{\mathit \chi}_{{{c1}}}{(3872)}}$ WIDTH FROM ${{\overline{\mathit D}}^{*0}}{{\mathit D}^{0}}$ MODE

${{\mathit \chi}_{{{c1}}}{(3872)}}$ DECAY MODES

Mode

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

Scale Factor/
Conf. Level

P(MeV/c)

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

$<2.7$ $\times 10^{-7}$

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

${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}{(1S)}}$

($4.3$ $\pm1.4$ ) $\%$

${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}{{\mathit J / \psi}{(1S)}}$

${{\mathit \omega}}{{\mathit \eta}_{{{c}}}{(1S)}}$

${{\mathit \rho}{(770)}^{0}}{{\mathit J / \psi}{(1S)}}$

($3.4$ $\pm1.1$ ) $\%$

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

($5.0$ $\pm1.9$ ) $\%$

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

${{\mathit D}^{0}}{{\overline{\mathit D}}^{0}}{{\mathit \pi}^{0}}$

($55$ $\pm28$ ) $\%$

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

($46$ $\pm16$ ) $\%$

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

${{\mathit D}^{0}}{{\overline{\mathit D}}^{0}}$

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

${{\mathit \pi}^{0}}{{\mathit \chi}_{{{c2}}}}$

${{\mathit \pi}^{0}}{{\mathit \chi}_{{{c1}}}}$

($3.8^{+1.9}_{-1.7}$ ) $\%$

${{\mathit \pi}^{0}}{{\mathit \chi}_{{{c0}}}}$

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

${{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit \chi}_{{{c0}}}}$

${{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit \chi}_{{{c1}}}}$

${{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit \chi}_{{{c2}}}}$

${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \chi}_{{{c0}}}}$

${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \chi}_{{{c1}}}}$

$<8$ $\times 10^{-3}$

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

$<2.7$ $\times 10^{-5}$

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

$<5$ $\times 10^{-3}$

▸ Radiative decays

▸ $\mathit C$-violating decays

[1]	BHARDWAJ 2011 does not observe this decay and presents a stronger 90$\%$ CL limit than this value. See measurements listings for details.

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