Decays of an exotic $1^{-+}$ hybrid meson resonance in QCD

Abstract

We present the first determination of the hadronic decays of the lightest exotic $J^{PC}=1^{-+}$ resonance in lattice QCD. Working with SU(3) flavor symmetry, where the up, down and strange quark masses approximately match the physical strange-quark mass giving $m_{\pi }\sim 700$ MeV, we compute finite-volume spectra on six lattice volumes which constrain a scattering system featuring eight coupled channels. Analytically continuing the scattering amplitudes into the complex energy plane, we find a pole singularity corresponding to a narrow resonance which shows relatively weak coupling to the open pseudoscalar--pseudoscalar, vector--pseudoscalar and vector--vector decay channels, but large couplings to at least one kinematically-closed axial-vector--pseudoscalar channel. Attempting a simple extrapolation of the couplings to physical light-quark mass suggests a broad ${\pi }_1$ resonance decaying dominantly through the $b_1\pi$ mode with much smaller decays into $f_1\pi$, $\rho \pi$, ${\eta }^{\prime }\pi$ and $\eta \pi$. A large total width is potentially in agreement with the experimental ${\pi }_1(1564)$ candidate state, observed in $\eta \pi$, ${\eta }^{\prime }\pi$, which we suggest may be heavily suppressed decay channels.

33 pages, 20 figures, small changes to match published version

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Cited by in corpus (36)

• An updated review of the new hadron states
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• Precision Studies of QCD in the Low Energy Domain of the EIC
• The Present and Future of QCD
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• Novel approaches in Hadron Spectroscopy
• Solving relativistic three-body integral equations in the presence of bound states
• Isospin-1/2 $D\pi$ scattering and the lightest $D_0^{\ast }$ resonance from lattice QCD
• One Born$-$Oppenheimer Effective Theory to rule them all: hybrids, tetraquarks, pentaquarks, doubly heavy baryons and quarkonium
• The phenomenology of the exotic hybrid nonet with ${\pi }_1(1600)$ and ${\eta }_1(1855)$
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• A simple alternative to the Breit-Wigner distribution
• $1^{-+}$ Hybrid in $J/\psi$ Radiative Decays from Lattice QCD
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• Charmonium ${\chi }_{c0}$ and ${\chi }_{c2}$ resonances in coupled-channel scattering from lattice QCD
• Constructing the $J^{P(C)}=1^{-(+)}$ light flavor hybrid nonet with the newly observed ${\eta }_1(1855)$
• Radiative production and decays of the exotic ${\eta }_1^{\prime }(1855)$ and its siblings
• Why quarkonium hybrid coupling to two S-wave heavy-light mesons is not suppressed
• Axial-vector $D_1$ hadrons in $D^{\ast }\pi$ scattering from QCD
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• Ordinary and exotic mesons in the extended Linear Sigma Model
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• Upper Limit on the Photoproduction Cross Section of the Spin-Exotic ${\pi }_1(1600)$
• Prospects for ${\gamma }^{\star }{\gamma }^{\star }\to \pi \pi$ via lattice QCD
• Investigating hybrid mesons with $0^{+-}$ and $2^{+-}$ exotic quantum numbers
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• Investigation of the Lightest Hybrid Meson Candidate with a Coupled-Channel Analysis of $\bar{p}p$-, ${\pi }^{-}p$- and $\pi \pi$-Data