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Near-threshold $$ \mathrm{D}\overline{\mathrm{D}} $$ spectroscopy and observation of a new charmonium state

Published version
Peer-reviewed

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Type

Article

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Authors

Aaij, R 
Abellán Beteta, C 
Adeva, B 
Adinolfi, M 
Aidala, CA 

Abstract

Using proton-proton collision data, corresponding to an integrated luminosity of 9fb−1, collected with the~LHCb detector between 2011 and 2018, a new narrow charmonium state, the X(3842) resonance, is observed in the decay modes X(3842)→D0D¯0 and X(3842)→D+D. The mass and the natural width of this state are measured to be \begin{eqnarray*} m_{X(3842)} & = & 3842.71 \pm 0.16 \pm 0.12 MeV/c^2,, \Gamma_{X(3842)} & = & 2.79 \pm 0.51 \pm 0.35 MeV,, \end{eqnarray*} where the first uncertainty is statistical and the~second is systematic. The observed mass and narrow natural width suggest the~interpretation of the new state as the~unobserved spin\nobreakdash-3 ψ3(13D3) charmonium state. In addition, prompt hadroproduction of the ψ(3770)~and χc2(3930) states is observed for the first time, and the parameters of these~states are measured to be \begin{eqnarray*} m_{\psi(3770)} & = & 3778.1 \pm 0.7 \pm 0.6 MeV/c^2,, m_{\chi_{c2}(3930)} & = & 3921.9 \pm 0.6 \pm 0.2 MeV/c^2,, \Gamma_{\chi_{c2}(3930)} & = &36.6 \pm 1.9 \pm 0.9 MeV,, \end{eqnarray*} where the first uncertainty is statistical and the~second is systematic.

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Keywords

Charm physics, Hadron-Hadron scattering (experiments), Heavy quark production, Quarkonium

Journal Title

Journal of High Energy Physics

Conference Name

Journal ISSN

1029-8479
1029-8479

Volume Title

2019

Publisher

Springer Science and Business Media LLC
Sponsorship
Science and Technology Facilities Council (ST/N000234/1)