Observation of structure in the $J/\psi$-pair mass spectrum

Abstract

Using proton-proton collision data at centre-of-mass energies of $\sqrt{s}=7$, $8$ and $13\mathrm{TeV}$ recorded by the LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$, the invariant mass spectrum of $J/\psi$ pairs is studied. A narrow structure around $6.9GeV/c^2$ matching the lineshape of a resonance and a broad structure just above twice the $J/\psi$ mass are observed. The deviation of the data from nonresonant $J/\psi$-pair production is above five standard deviations in the mass region between $6.2$ and $7.4GeV/c^2$, covering predicted masses of states composed of four charm quarks. The mass and natural width of the narrow $X(6900)$ structure are measured assuming a Breit--Wigner lineshape.

arXiv commentAll figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-011.html (LHCb public pages)

References in corpus (49)

• A Brief Introduction to PYTHIA 8.1
• LHCb Detector Performance
• PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays
• Non-Standard Heavy Mesons and Baryons, an Experimental Review
• sPlot: a statistical tool to unfold data distributions
• Pentaquark and Tetraquark states
• QCD and strongly coupled gauge theories: challenges and perspectives
• Observation of the doubly charmed baryon ${\Xi }_{cc}^{++}$
• Decay Chain Fitting with a Kalman Filter
• Measurement of J/psi production in pp collisions at sqrt(s)=7 TeV
• Baryons with two heavy quarks: Masses, production, decays, and detection
• Understanding the newly observed heavy pentaquark candidates
• $QQ\bar{Q}\bar{Q}$ states: masses, production, and decays
• Observation of $J/\psi$ pair production in pp collisions at $\sqrt{s}=7TeV$
• Hunting for exotic doubly hidden-charm/bottom tetraquark states
• HELAC-Onia: an automatic matrix element generator for heavy quarkonium physics
• Model-independent evidence for $J/\psi p$ contributions to ${\Lambda }_b^0\to J/\psi p{K}^{-}$ decays
• A non-relativistic model for the $[cc][\bar{c}\bar{c}]$ tetraquark
• Heavy-flavored tetraquark states with the $QQ\bar{Q}\bar{Q}$ configuration
• Spectrum of fully-heavy tetraquarks from a diquark+antidiquark perspective
• Four-quark spectroscopy within the hyperspherical formalism
• All-heavy tetraquarks
• Measurement of the prompt $J/\psi$ pair production cross-section in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• All-charm tetraquarks
• J/psi-Pair Production at Large Momenta: Indications for Double-Parton Scatterings and Large alpha_s^5 Contributions
• A $bb\bar{b}\bar{b}$ di-bottomonium at the LHC?
• Spectrum of the fully-heavy tetraquark state $QQ{\bar{Q}}^{\prime }{\bar{Q}}^{\prime }$
• String dynamics and metastability of fully-heavy tetraquarks
• Production of J/psi+eta(c) vs. J/psi+J/psi at the LHC: Impact of Real alpha_s^5 corrections
• Beauty-full Tetraquarks
• Production of J/psi and Upsilon mesons in pp collisions at sqrt(s) = 8 TeV
• Proton Structure in Transverse Space and the Effective Cross Section
• Observation and measurements of the production of prompt and non-prompt $J/\psi$ mesons in association with a $Z$ boson in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Analysis of the vector and axialvector $QQ\bar{Q}\bar{Q}$ tetraquark states with QCD sum rules
• Interplay of quark and meson degrees of freedom in near-threshold states: A practical parametrisation for line shapes
• Measurement of b-hadron masses
• Impact of $J/\psi$ pair production at the LHC and predictions in nonrelativistic QCD
• Search for $bb\bar{b}\bar{b}$ tetraquark decays in 4 muons, $B^{+}{B}^{-}$, $B^0{\bar{B}}^0$ and $B_s^0{\bar{B}}_s^0$ channels at LHC
• Search for beautiful tetraquarks in the ${\rm Y}(1S)\mu \mu$ invariant-mass spectrum
• Double-quarkonium production at a fixed-target experiment at the LHC (AFTER@LHC)
• Scale Factor in Double Parton Collisions and Parton Densities in Transverse Space
• Minijets and the Two-Body Parton Correlation
• Production of $J/\psi +{\chi }_c$ and $J/\psi +J/\psi$ with real gluon emission at LHC
• Observation of associated production of a $Z$ boson with a $D$ meson in the~forward region
• Charm-meson Triangle Singularity in $e^{+}{e}^{-}$ Annihilation into $D^{\ast 0}{\bar{D}}^0+\gamma$
• Fully-heavy tetraquarks: $bb\bar{c}\bar{c}$ and $bc\bar{b}\bar{c}$
• $f_2(1810)$ as a triangle singularity
• Isospin amplitudes in ${\Lambda }_b^0\to J/\psi \Lambda ({\Sigma }^0)$ and ${\Xi }_b^0\to J/\psi {\Xi }^0(\Lambda )$ decays
• ${\rm Y}$-meson pair production at LHC

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• An updated review of the new hadron states
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• The two-photon decay of X(6900) from light-by-light scattering at the LHC
• A high-energy QCD portal to exotic matter: Heavy-light tetraquarks at the HL-LHC
• Fully charmed tetraquarks from LHC to FCC: Natural stability from fragmentation
• Improved understanding of the peaking phenomenon existing in the new di-$J/\psi$ invariant mass spectrum from the CMS Collaboration
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