Hadronic transitions from Upsilon(4S) as a probe of four-quark admixture

Abstract

It is argued that the observed enhancement of the hadronic transition Upsilon(4S) -> Upsilon(1S) eta relative to Upsilon(4S) -> Upsilon(1S) pi pi can be explained if the resonance Upsilon(4S) contains an admixture of a four-quark component, possibly due to the coupling to the meson channel B \bar B. A test of the discussed mechanism by searching for the transition Upsilon(4S) -> Upsilon(1S) eta'(958) is suggested. Some properties of possible four-quark states related to the suggested one by the heavy quark spin symmetry are also discussed.

6 pages, some points are clarified, a reference added

References in corpus (3)

• Charmonium
• Study of hadronic transitions between Y states and observation of Y(4S)-> eta Y(1S) decay
• Observation of Upsilon(2S) -> eta Upsilon(1S) and search for related transitions

Cited by in corpus (8)

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• Observation of $e^{+}{e}^{-}\to \eta J/\psi$ at center-of-mass energy $sqrts=4.009$ GeV
• Heavy quark spin symmetry breaking in near-threshold $J^{PC}=1^{--}$ quarkonium-like resonances
• Bottomonium-like states: physics case for energy scan above the $B\bar{B}$ threshold at Belle-II
• First observation of the hadronic transition ${\rm Y}(4S)\to \eta h_b(1P)$ and new measurement of the $h_b(1P)$ and ${\eta }_b(1S)$ parameters
• Observation of ${\rm Y}(4S)\to {\eta }^{\prime }{\rm Y}(1S)$
• Results in $B_s$ physics and bottomonium spectroscopy using the Belle ${\rm Y}(5S)$ data
• Experimental review of the ${\rm Y}(1S,2S,3S)$ physics at $e^{+}{e}^{-}$ colliders and the LHC