Anomalous dipion invariant mass distribution of the ${\rm Y}(4S)$ decays into ${\rm Y}(1S){\pi }^{+}{\pi }^{-}$ and ${\rm Y}(2S){\pi }^{+}{\pi }^{-}$

Abstract

To solve the discrepancy between the experimental data on the partial widths and lineshapes of the dipion emission of ${\rm Y}(4S)$ and the theoretical predictions, we suggest that there is an additional contribution which was not taken into account in previous calculations. Noticing that the mass of ${\rm Y}(4S)$ is above the production threshold of $B\bar{B}$, the contribution of the sequential process ${\rm Y}(4S)\to B\bar{B}\to {\rm Y}(nS)+S\to {\rm Y}(nS)+{\pi }^{+}{\pi }^{-}$ ($n=1,2$) may be sizable, and its interference with that from the direct production would be important. The goal of this work is to investigate if a sum of the two contributions with a relative phase indeed reproduces the data. Our numerical results on the partial widths and the lineshapes $d\Gamma ({\rm Y}(4S)\to {\rm Y}(2S,1S){\pi }^{+}{\pi }^{-})/d(m_{{\pi }^{+}{\pi }^{-}})$ are satisfactorily consistent with the measurements, thus the role of this mechanism is confirmed. Moreover, with the parameters obtained by fitting the data of the Belle and Babar collaborations, we predict the distributions $d\Gamma ({\rm Y}(4S)\to {\rm Y}(2S,1S){\pi }^{+}{\pi }^{-})/d\cos \theta$ which have not been measured yet.

5 pages, 3 tables and 4 figures. Accepted by Eur. Phys. J. C

References in corpus (3)

• Observation of anomalous Upsilon(1S)pi+pi- and Upsilon(2S)pi+pi- production near the Upsilon(5S) resonance
• Scalar Resonance Contributions to the Dipion Transition Rates of ${\rm Y}(4S,5S)$ in the re-scattering model
• Bottomonium dipion transitions

Cited by in corpus (12)

• Determination of spin and parity of the $Z_c(3900)$
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• Spectroscopic survey of higher-lying states of $B_c$ meson family
• Using $X(3823)\to J/\psi {\pi }^{+}{\pi }^{-}$ to identify coupled-channel effects
• Production of the $Z_b^{(\prime )}$ states from the ${\rm Y}(5S,6S)$ decays
• Exploring the ${\rm Y}(4S,5S,6S)\to h_b(1P)\eta$ hidden-bottom hadronic transitions
• How higher charmonia shape the puzzling data of the $e^{+}{e}^{-}\to \eta J/\psi$ cross section
• Charged charmoniumlike structures in the $e^{+}{e}^{-}\to \psi (3686){\pi }^{+}{\pi }^{-}$ process based on the ISPE mechanism
• Higher strangeonium decays into light flavor baryon pairs like $\Lambda \bar{\Lambda }$, $\Sigma \bar{\Sigma }$, and $\Xi \bar{\Xi }$
• Hindered magnetic dipole transitions between P-wave bottomonia and coupled-channel effects
• Unified description of BaBar and Belle data on the bottomonia decays Upsilon(mS) -> Upsilon(nS) pi+ pi-
• Non-$D\bar{D}$ Decays into Light Meson Pairs of the $D$-Wave Charmonium ${\psi }_3(3842)$