Study of the XYZ states at the BESIII

Abstract

With its unique data samples at energies of 3.8–4.6 GeV, the BESIII experiment made a significant contribution to the study of charmonium and charmonium-like states, i.e., the XYZ states.We review the results for observations of the Z_c(3900) and Z_c(4020) states, the X(3872) in e⁺e⁻ annihilation, and charmonium ψ(1³D₂) state, as well as measurements of the cross-sections of ωχ_cJ and ηJ/ψ, and the search for e⁺e⁻→ γχ_cJ and γY (4140). We also present data from BESIII that may further strengthen the study of the XYZ and conventional charmonium states, and discuss perspectives on future experiments.

Keywords

charmonium / exotic states / e⁺e⁻ annihilation / hadronic transitions / radiative transtitions

References

[1] A. J. Bevan, . (BaBar and Belle Collaborations), The physics of the B factories,  Eur. Phys. J. C  74, 3026 (2014)

[2] For a recent review, see: N. Brambilla, ., Heavy quarkonium: Progress, puzzles, and opportunities,  Eur. Phys. J. C  71, 1534 (2011)

[3] M. Ablikim, . (BESIII Collaboration), Design and construction of the BESIII detector,  Nucl. Instrum. Methods Phys. Res. Sect. A  614, 345 (2010)

[4] D. M. Asner, ., Physics at BES-III,  Int. J. Mod. Phys. A  24, S1 (2009)

[5] M. Ablikim, . (BESIII Collaboration), Observation of a charged charmoniumlike structure in  e  ⁺ e⁻ → π  ⁺ π  ⁻ J/ψ at  s= 4.26 GeV,  Phys. Rev. Lett. 110, 252001 (2013)

[6] M. Ablikim, . (BESIII Collaboration), Measurements of the center-of-mass energies via the di-muon process at BESIII, to be submitted to  Chin. Phys. C

[7] M. Ablikim, . (BESIII Collaboration), Precision measurement of the integrated luminosity of the data taken by BESIII at center of mass energies between 3.810 GeV and 4.600 GeV, arXiv: 1503.03408 [hep-ex]

[8] Z. Q. Liu, . (Belle Collaboration), Study of  e  ⁺ e⁻ → π  ⁺ π  ⁻ J/ψ and observation of a charged charmoniumlike state at Belle,  Phys. Rev. Lett.  110, 252002 (2013)

[9] T. Xiao, S. Dobbs, A. Tomaradze, and K. K. Seth, Observation of the charged hadron  Z^±_c (3900) and evidence for the neutral  Z⁰_c (3900) in  e  ⁺ e⁻ → π  π  J/ψ at  s = 4170 MeV,  Phys. Lett. B  727, 366 (2013)

[10] M. Ablikim, . (BESIII Collaboration), Observation of  Z⁰_c (3900) in  e  ⁺ e⁻ → π  ⁰ π  ⁰ J/ψ ,  Phys. Rev. Lett.  110, 252001 (2013)

[11] M. Ablikim, . (BESIII Collaboration), Observation of a charged (DD ¯*)⁻ mass peak in   e  ⁺ e⁻ → π+(DD ¯*)⁻ at  E_cm=4.26 GeV,  Phys. Rev. Lett.  112, 022001 (2014)

[12] K. A. Olive, . (Particle Data Group), The Review of Particle Physics,  Chin. Phys. C  38, 090001 (2014)

[13] M. Ablikim, . (BESIII Collaboration), Observation of  e  ⁺ e  ⁻ → η J/ψ at center-of-mass energy  s = 4.009 GeV,  Phys. Rev. D  86, 071101 (2012)

[14] M. Ablikim, . (BESIII Collaboration), Observation of a charged charmoniumlike structure  Z_c(4020) and search for the  Z_c(3900) in  e  ⁺ e  ⁻ → π  ⁺ π  ⁻ h_c,  Phys. Rev. Lett.  111, 242001 (2013)

[15] M. Ablikim, . (BESIII Collaboration), Observation of   e  ⁺ e  ⁻ → π  ⁰ π  ⁰ h_c hc and a neutral charmoniumlike structure  Z_c(4020)⁰,  Phys. Rev. Lett. 113(21), 212002 (2014)

[16] M. Ablikim, . (BESIII Collaboration), Observation of a charged charmoniumlike structure in   e  ⁺ e⁻ → (D^*D ¯*)^± π^∓ at  s= 4.26 GeV,  Phys. Rev. Lett. 112, 132001 (2014)

[17] M. Ablikim, . (BESIII Collaboration), Observation of a neutral charmoniumlike state  Z_c(4025)⁰ in e  ⁺ e⁻ → (D^*D ¯*)⁰ π⁰, arXiv: 1507.02404 [hep-ex]

[18] M. Ablikim, . (BESIII Collaboration), Observation of e  ⁺ e⁻  →  γ X(3872) at BESIII,  Phys. Rev. Lett.  112(9), 092001 (2014)

[19] K. T. Chao, Z. G. He, D. Li, and C. Meng, Search for  C = + charmonium states in e  ⁺ e⁻  →  γ + X at BEPCII/BESIII, arXiv: 1310.8597 [hep-ph]

[20] F. K. Guo, C. Hanhart, U. G. Meißner, Q. Wang, and Q. Zhao, Production of the X(3872) in charmonia radiative decays,  Phys. Lett. B  725, 127 (2013)

[21] C. Z. Yuan (for the BES and Belle Collaborations), Exotic Hadrons, arXiv: 0910.3138 [hep-ex]. We take 5% from the range presented in the paper of 2.3%<  B(X(3872) → π  ⁺π  ⁻ J/ψ)<6.6% at 90% C.L.

[22] M. Ablikim, . (BESIII Collaboration), Observation of the  ψ(1  ³D₂) state in  e  ⁺ e⁻  → π  ⁺ π  ⁻ γχ  _c1 at BESIII,  Phys. Rev. Lett.  115(1), 011803 (2015)

[23] V. Bhardwaj, . (Belle Collaboration), Evidence of a new narrow resonance decaying to χ_c1γ in  B →  χ_c1γK,  Phys. Rev. Lett.  111(3), 032001 (2013)

[24] A. Kolmogorov, Sulla determinazione empirica di una legge di distribuzione,  G. Inst. Ital. Attuari.  4, 83 (1933)

[25] E. Eichten, K. Gottfried, T. Kinoshita, K. D. Lane, and T. M. Yan, Charmonium: The Model,  Phys. Rev. D   17, 3090 (1978) [Phys. Rev. D 21, 313 (1980)]

[26] T. Barnes, S. Godfrey, and E. S. Swanson, Higher charmonia,  Phys. Rev. D  72, 054026 (2005)

[27] S. Godfrey and N. Isgur, Mesons in a relativized quark model with chromodynamics,  Phys. Rev. D  32, 189 (1985)

[28] W. Kwong, J. L. Rosner, and C. Quigg, Heavy quark systems,  Ann. Rev. Nucl. Part. Sci.  37, 325 (1987)

[29] D. Ebert, R. N. Faustov, and V. O. Galkin, Properties of heavy quarkonia and B_c mesons in the relativistic quark model,  Phys. Rev. D  67, 014027 (2003)

[30] E. J. Eichten, K. Lane, and C. Quigg, Charmonium levels near threshold and the narrow state  X(3872) →  π⁺ π  ⁻ J/ψ,  Phys. Rev. D  69, 094019 (2004)

[31] B. Q. Li and K. T. Chao, Higher charmonia and X,Y,Z states with screened potential,  Phys. Rev. D  79, 094004 (2009)

[32] M. Blank and A. Krassnigg, Bottomonium in a Bethe–Salpeter-equation study,  Phys. Rev. D  84, 096014 (2011)

[33] C. F. Qiao, F. Yuan, and K. T. Chao, A Crucial test for color octet production mechanism in  Z⁰ decays,  Phys. Rev. D  55, 4001 (1997)

[34] M. Ablikim, . (BESIII Collaboration), Evidence fore  ⁺ e⁻ → γχ_c1,2 at center-of-mass energies from 4.009 to 4.360 GeV,  Chin. Phys. C  39(4), 041001 (2015)

[35] M. Ablikim, . (BESIII Collaboration), Search for the  Y (4140) via e  ⁺ e⁻ →  γJ/ψ at  s=4.23, 4.26, and 4.36 GeV,  Phys. Rev. D  91(3), 032002 (2015)

[36] T. Branz, T. Gutsche, and V. E. Lyubovitskij, Hadronic molecule structure of the  Y (3940) and  Y (4140),  Phys. Rev. D  80, 054019 (2009)

[37] T. Aaltonen, . (CDF Collaboration), Observation of the  Y (4140) structure in the  J/ψ φ mass spectrum in B^± → J/ψ φK decays, arXiv: 1101.6058 [hep-ex]

[38] M. Ablikim, . (BESIII Collaboration), Study of e  ⁺ e⁻ →  ωχ_cJat center-of-mass energies from 4.21 to 4.42 GeV,  Phys. Rev. Lett.  114(9), 092003 (2015)

[39] L. Y. Dai, M. Shi, G. Y. Tang, and H. Q. Zheng, Nature of  X(4260),  Phys. Rev. D  92(1), 014020 (2015)

[40] Chang-Zheng Yuan, Evidence for resonant structures in e  ⁺ e⁻ →  π  ⁺ π  ⁻ h  _c,  Chin. Phys. C   38, 043001 (2014)

[41] B. Aubert, . (BaBar Collaboration), Observation of a broad structure in the π  ⁺ π  ⁻ J/ψ mass spectrum around 4.26-GeV/c²  Phys. Rev. Lett.   95, 142001 (2005)

[42] L. Ma, X. H. Liu, X. Liu, and S. L. Zhu, Strong decays of the XYZ states,  Phys. Rev. D  91(3), 034032 (2015)

[43] M. Ablikim, . (BESIII Collaboration), Measurement of the e  ⁺ e⁻  →  ηJ/ψ cross section and search for e  ⁺ e⁻ → π⁰ J/ψ at center-of-mass energies between 3.810 and 4.600 GeV,  Phys. Rev. D  91(11), 112005 (2015)

[44] X. L. Wang, . (Belle Collaboration), Observation of  ψ(4040) and  ψ(4160) decay into  ηJ/ψ,  Phys. Rev. D  87(5), 051101 (2013)

[45] G. Pakhlova, . (Belle Collaboration), Observation of a near-threshold enhancement in the e  ⁺ e⁻ →  Λ  ⁺  _c Λ  ⁻ _c cross section using initial-state radiation,  Phys. Rev. Lett.  101, 172001 (2008)

[46] P. Guo, A. P. Szczepaniak, G. Galata, A. Vassallo, and E. Santopinto, Heavy quarkonium hybrids from Coulomb gauge QCD,  Phys. Rev. D  78, 056003 (2008)

[47] J. J. Dudek and E. Rrapaj, Charmonium in lattice QCD and the non-relativistic quark-model,  Phys. Rev. D  78, 094504 (2008)

[48] C. P. Shen, . (Belle Collaboration), Updated cross section measurement of e  ⁺ e⁻ →  K  ⁺K  ⁻ J/ψ and K⁰_S K⁰_S J/ψ via initial state radiation at Belle,  Phys. Rev. D  89(7), 072015 (2014)

[49] T. Abe, . (Belle-II Collaboration), Belle II technical design report, arXiv: 1011.0352 [physics.ins-det]

[50] Z. G. Zhao, Talk at the International Workshop on Physics at Future High Intensity Collider 2–7 GeV in China, January 13–16, 2015, University of Science and Technology of China (USTC), Hefei, China

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag Berlin Heidelberg