Study of the ${\psi }_2(3823)$ and ${\chi }_{c1}(3872)$ states in $B^{+}\to \left(J\psi {\pi }^{+}{\pi }^{-}\right)K^{+}$ decays

Abstract

The decays $B^{+}\to J/\psi {\pi }^{+}{\pi }^{-}{K}^{+}$ are studied using a data set corresponding to an integrated luminosity of 9fb${}^{-1}$ collected with the LHCb detector in proton-proton collisions between 2011 and 2018. Precise measurements of the ratios of branching fractions with the intermediate ${\psi }_2(3823)$, ${\chi }_{c1}(3872)$ and $\psi (2S)$ states are reported. The decay of $B^{+}\to {\psi }_2(3823)K^{+}$ with ${\psi }_2(3823)\to J\psi {\pi }^{+}{\pi }^{-}$ is observed for the first time with a significance of 5.1 standard deviations. The mass differences between the ${\psi }_2(3823)$, ${\chi }_{c1}(3872)$ and $\psi (2S)$ states are measured to be $$\begin{array}{rcl}{m}_{{\chi }_{c1(3872)}}-m_{{\psi }_2(3823)}& =& 47.50\pm 0.53\pm 0.13MeV/c^2,\\ m_{{\psi }_2(3823)}-m_{\psi (2S)}& =& 137.98\pm 0.53\pm 0.14MeV/c^2,\\ m_{{\chi }_{c1}(3872)}-m_{\psi (2S)}& =& 185.49\pm 0.06\pm 0.03MeV/c^2,\end{array}$$ resulting in the most precise determination of the ${\chi }_{c1}(3782)$ mass. The width of the ${\psi }_2(3823)$ state is found to be below 5.2MeV at 90\% confidence level. The Breit-Wigner width of the ${\chi }_{c1}(3872)$ state is measured to be $${\Gamma }_{{\chi }_{c1}(3872)}^{\mathrm{BW}}=0.96_{-0.18}^{+0.19}\pm 0.21\mathrm{MeV},$$ which is inconsistent with zero by 5.5 standard deviations.

arXiv comment26 pages, 3 figures. All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-009.html (LHCb public pages). arXiv admin note: text overlap with arXiv:2011.01867

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Cited by in corpus (38)

• The ALICE experiment: a journey through QCD
• Study of the lineshape of the ${\chi }_{c1}(3872)$ state
• The nature of $X(3872)$ from high-multiplicity $pp$ collisions
• Observation of multiplicity-dependent prompt ${\chi }_{c1}(3872)$ and $\psi (2S)$ production in $pp$ collisions
• The production of doubly charmed exotic hadrons in heavy ion collisions
• A Phenomenological analysis on isospin-violating decay of $X(3872)$
• Production of $X(3872)$ at High Multiplicity
• XYZ spectroscopy at electron-hadron facilities: Exclusive processes
• Triangle Singularity in the Production of $T_{cc}^{+}$(3875) and a Soft Pion
• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• Observation of resonance structures in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\psi }_2(3823)$ and mass measurement of ${\psi }_2(3823)$
• Evidence for $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ produced in single-tag two-photon interactions
• Decipher the width of the $X(3872)$ via the QCD sum rules
• $D^{\pm }{D}^{\ast \mp }$ Hadronic Atom as a Key to Revealing the $X(3872)$ Mystery
• Galilean-Invariant XEFT at Next-to-Leading Order
• Bulk reconstruction using timelike entanglement in (A)dS
• $D{\bar{D}}^{\ast }$ scattering and ${\chi }_{c1}(3872)$ in nuclear matter
• Hadronic decays of the heavy-quark-spin molecular partner of $T_{cc}^{+}$
• Study of the lineshape of $X(3872)$ using $B$ decays to $D^0\overline{D}{}^{\ast 0}K$
• Observation of a New $X(3872)$ Production Process $e^{+}{e}^{-}\to \omega X(3872)$
• Modification of ${\chi }_{c1}$(3872) and $\psi$(2$S$) production in $p$Pb collisions at $\sqrt{s_{NN}}=8.16$ TeV
• Interpretation of neutral charm mesons near threshold as unparticles
• Possible precise measurements of the $X(3872)$ mass with the $e^{+}{e}^{-}\to {\pi }^0\gamma X(3872)$ and $p\bar{p}\to \gamma X(3872)$ reactions
• Search for new decay modes of the ${\psi }_2(3823)$ and the process $e^{+}{e}^{-}\to {\pi }^0{\pi }^0{\psi }_2(3823)$
• The electromagnetic decays of $X(3823)$ as the ${\psi }_2(1^3{D}_2)$ state and its radial excited states
• Dispersive analysis of the isospin breaking in the $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ and $X(3872)\to J/\psi {\pi }^{+}{\pi }^0{\pi }^{-}$ decays
• Search for the decay ${\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}$
• Point Production of a Nonrelativistic Unparticle Recoiling Against a Particle
• Search for $X(3872)\to {\pi }^0{\chi }_{c0}$ and $X(3872)\to \pi \pi {\chi }_{c0}$ at BESIII
• Study of $e^{+}{e}^{-}\to \omega X(3872)$ and $\gamma X(3872)$ from 4.66 to 4.95 GeV
• On the precise measurement of the $X(3872)$ mass and its counting rate
• $S$-wave contributions to the $B_{(s)}\to {\chi }_{c1}(\pi \pi ,K\pi ,KK)$ decays
• Study of $e^{+}{e}^{-}\to {\pi }^{0}X(3872)\gamma$ and search for $Z_c(4020{)}^0\to X(3872)\gamma$
• Constrain the ${\chi }_{cJ}\to D^{(\ast )}{\bar{D}}^{(\ast )}$ effective couplings via the $X(3872)\to {\pi }^0{\chi }_{cJ}$ decays
• Two nearby states in the $X(3872)$ region: Resolving the radiative-decay ratio tension with ${\eta }_{c2}$
• Prospects for observing the missing $2D$ and $1F$ charmonium states around 4 GeV
• Search for the $e^{+}{e}^{-}\to \varphi {\chi }_{c1}(3872)$ process at BESIII
• Observation of the decay ${\chi }_{c1}(3872)\to J/\psi {\mu }^{+}{\mu }^{-}$