${\boldsymbol {\boldsymbol c}}$ ${\boldsymbol {\overline{\boldsymbol c}}}$ MESONS
(including possibly non- ${\boldsymbol {\boldsymbol q}}$ ${\boldsymbol {\overline{\boldsymbol q}}}$ states)
INSPIRE search

${{\boldsymbol \chi}_{{c1}}{(3872)}}$ $I^G(J^{PC})$ = $0^+(1^{+ +})$


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 our note on ``Developments in Heavy Quarkonium Spectroscopy''.
${{\mathit \chi}_{{c1}}{(3872)}}$ MASS FROM ${{\mathit J / \psi}}{{\mathit X}}$ MODE   $3871.69 \pm0.17$ MeV 
${{\mathit \chi}_{{c1}}{(3872)}}$ MASS FROM ${{\overline{\mathit D}}^{*0}}{{\mathit D}^{0}}$ MODE
${\boldsymbol m}_{{{\boldsymbol \chi}_{{c1}}{(3872)}}}–{\boldsymbol m}_{{{\boldsymbol J / \psi}}}$
${\mathit m}_{{{\mathit \chi}_{{c1}}{(3872)}}}–{\mathit m}_{{{\mathit J / \psi}}}$   $775 \pm4$ MeV 
${\mathit m}_{{{\mathit \chi}_{{c1}}{(3872)}}}–{\mathit m}_{{{\mathit \psi}{(2S)}}}$
${{\mathit \chi}_{{c1}}{(3872)}}$ WIDTH   $<1.2$ MeV  CL=90.0%
${{\mathit \chi}_{{c1}}{(3872)}}$ WIDTH FROM ${{\overline{\mathit D}}^{*0}}{{\mathit D}^{0}}$ MODE
$\Gamma_{1}$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ 1936
$\Gamma_{2}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}{(1S)}}$ $>3.2\%$650
$\Gamma_{3}$ ${{\mathit \rho}^{0}}{{\mathit J / \psi}{(1S)}}$ -1
$\Gamma_{4}$ ${{\mathit \omega}}{{\mathit J / \psi}{(1S)}}$ $>2.3\%$-1
$\Gamma_{5}$ ${{\mathit D}^{0}}{{\overline{\mathit D}}^{0}}{{\mathit \pi}^{0}}$ $>40\%$117
$\Gamma_{6}$ ${{\overline{\mathit D}}^{*0}}{{\mathit D}^{0}}$ $>30\%$3
$\Gamma_{7}$ ${{\mathit \gamma}}{{\mathit \gamma}}$ 1936
$\Gamma_{8}$ ${{\mathit D}^{0}}{{\overline{\mathit D}}^{0}}$ 520
$\Gamma_{9}$ ${{\mathit D}^{+}}{{\mathit D}^{-}}$ 502
$\Gamma_{10}$ ${{\mathit \gamma}}{{\mathit \chi}_{{c1}}}$ 344
$\Gamma_{11}$ ${{\mathit \gamma}}{{\mathit \chi}_{{c2}}}$ 303
$\Gamma_{12}$ ${{\mathit \gamma}}{{\mathit J / \psi}}$ $>7\times 10^{-3}$697
$\Gamma_{13}$ ${{\mathit \gamma}}{{\mathit \psi}{(2S)}}$ $>4\%$181
$\Gamma_{14}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \eta}_{{c}}{(1S)}}$ not seen746
$\Gamma_{15}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \chi}_{{c1}}}$ not seen218
$\Gamma_{16}$ ${{\mathit p}}{{\overline{\mathit p}}}$ not seen1693