Observation of an Anomalous Line Shape of the η′π+π− Mass Spectrum near the pp¯ Mass Threshold in J/ψ→γη′π+π−

In this paper we study the $$J/\Psi p$$J/Ψp spectroscopy in the process of $$\Lambda _b\rightarrow J/\Psi p K^-$$Λb→J/ΨpK-. The final state interactions of coupled channel $$J/\Psi p$$J/Ψp–$$\bar{D} \Sigma _c$$D¯Σc–$$\bar{D}^{*} \Sigma _c$$D¯∗Σc are constructed based on K-matrix with the Chew–Mandelstam function. We build the $$\Lambda _b\rightarrow J/\Psi p K^-$$Λb→J/ΨpK- amplitude according to the Au–Morgan–Pennington method. The event shape is fitted and the decay width of $$\Lambda _b\rightarrow J/\Psi p K^-$$Λb→J/ΨpK- is used to constrain the parameters, too. With the amplitudes we extract out the poles and their residues. Our amplitude and pole analysis suggest that the $$P_c(4312)$$Pc(4312) should be $$\bar{D}\Sigma _c$$D¯Σc molecule, the $$P_c(4440)$$Pc(4440) could be an S-wave compact pentaquark state, and the structure around $$P_c(4457)$$Pc(4457) is caused by the cusp effect. The future experimental measurement of the decays of $$\Lambda _b\rightarrow \bar{D}\Sigma _c K^-$$Λb→D¯ΣcK- and $$\Lambda _b\rightarrow \bar{D}^*\Sigma _c K^-$$Λb→D¯∗ΣcK- would further help to study the nature of these resonances.

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“…Indeed, this structure is very similar to that of the η π + π − line shape aroundp p threshold, see Fig. 4 of [46] and Fig. 4 of [47].…”

Section: Fitting Strategy and Pole Analysissupporting

confidence: 65%

Pole analysis on the hadron spectroscopy of $$\Lambda _b\rightarrow J/\Psi p K^-$$

et al. 2020

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“…The X(1835) was first observed in J/ψ → γπ + π − η ′ [14], and it was also observed in PWA of the J/ψ → γK s K s η, and its spin-parity was determined to be J PC = 0 − [15]. Recent BESIII studies based on about 1.3 billion J/ψ decay events suggest that X(1835) could be either a p p molecule-like state or a p p bound state [16]. Using a sample of 1.3 billion J/ψ events, two resonances were observed in J/ψ → γγϕ at BESIII [17], whose masses and widths are close to η(1475) and X(1835).…”

Section: The Structure Near P P Thresholdmentioning

confidence: 89%

Light meson spectroscopy at BESIII

Han¹

2022

Proceedings of Particles and Nuclei International Conference 2021 — PoS(PANIC2021)

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Light meson spectroscopy plays an important role in understanding the Quantum Chromodynamics in non-perturbative energy region and the decay dynamics of unconventional hadronic states. BESIII has collected the largest J/ψ and ψ ′ data samples in the world, which provides an unprecedented opportunity to study the light meson spectroscopy. The paper presents some highlights on light meson spectroscopy achieved in BESIII, such as search for glueball candidates, studies of the structure near p p threshold and studies of strange quarkonium.

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“…And then, BESIII not only confirmed X(1835) but also found two structures X(2120) and X(2370) [23] by analyzing the same decay process. With accumulation of experimental data, BESIII again studied J/ψ → γη π + π − channel [24]. And then, X(2370) and X(2500) were reported by BE-SIII in analyzing the J/ψ → γη π + π − [24] and J/ψ → γφφ [25] decays, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…With accumulation of experimental data, BESIII again studied J/ψ → γη π + π − channel [24]. And then, X(2370) and X(2500) were reported by BE-SIII in analyzing the J/ψ → γη π + π − [24] and J/ψ → γφφ [25] decays, respectively. Stimulated by these BESIII observation, Lanzhou group found two Regge trajectories [5,6], which are composed of these η mesons listed in PDG [17] and these observed X(1835), X(2120), X(2370) and X(2500).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, it is a suitable time to carry out the theoretical study of the properties of these potential higher radial excitations in the light isoscalar pseudoscalar meson family. Another topic of this work is to discuss the possible search for them by combing with the present BESIII experimental data [22][23][24]. However, we have to face a fact that the masses of η(7S ) and η (7S ) are close to that of η c (1S ), which results in the difficulty of detect the signals of η(7S ) and η (7S ).…”

Section: Introductionmentioning

confidence: 99%

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Potential higher radial excitations in the light pseudoscalar meson family

Wang,

Zhou,

Pang

et al. 2020

Preprint

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Inspired by the event accumulation around 2.6 GeV in the η π + π − invariant mass spectrum of J/ψ → γη π + π − , which was reported by the BESIII Collaboration, we carry out the study of the mass spectrum and decay behavior of four radial excitations in the pseudoscalar meson family, which include η ( ) (6S ) and η ( ) (7S ). Combining with these analysis, we present the calculation of the reactions induced by pion or kaon on proton target which are relevant to these four discussed states. According to this information, we give concrete experimental suggestion of searching for them, which will become new task to future experiments.

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Observation of an Anomalous Line Shape of the η′π+π− Mass Spectrum near the pp¯ Mass Threshold in J/ψ→γη′π+π−

Cited by 3 publications

References 49 publications

Pole analysis on the hadron spectroscopy of $$\Lambda _b\rightarrow J/\Psi p K^-$$

Pole analysis on the hadron spectroscopy of $$\Lambda _b\rightarrow J/\Psi p K^-$$

Light meson spectroscopy at BESIII

Potential higher radial excitations in the light pseudoscalar meson family

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