Heavy Quarkonium Physics continues to be a focus of the work done by the CLEO Collaboration. We present several results in the spectroscopy of both bottomonium and charmonium systems using CLEO's data sets taken at the Upsilon(3S), Upsilon(2S) and Psi(2S) resonances.
In the present work, we study the OZI-allowed three body open flavor decay properties of higher vector charmonium and bottomonium states with an extended quark pair creation model. For the bottomonium system, we get that (i) the $BBπ$ and $B^*B^*π$ partial decay widths of the $Υ(5S)$ state are consistent with the experiment, and the $BB^*π$ partial decay width of the $Υ(5S)$ state is smaller but very close to the Belle's experiment. Meanwhile, (ii) the $BB^*π$ and $B^*B^*π$ decay widths of $Υ(11020)$ can reachs $2\sim3$ MeV. In addition, (iii) for the most of higher vector charmonium states, t…
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+e^-$ collider is an upgrade of the B factory facility at KEK in Tsukuba, Japan. The experiment began operation in 2019 and aims to record a factor of 50 times more data than its predecessor. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now number in the dozens, and represent the emergence of a new category within quantum chromodynamics. We present recent results obtained from Belle II data, and the future prospects…
Inclusive production of $ΥJ/ψ$ pair in proton-proton interation at LHCb is considered. This process is forbidden at leading order of perturbation theory, so such channels as double parton scattering, $χ_bχ_c$ pair production with subsequent radiative decays of $P$-wave quarkonia, contributions of color-octet states, and NLO corrections are studied in details. For all these channels we present theoretical predictions of total cross sections at LHCb and distributions over different kinematical variables. According to presented in the paper results, double parton interaction gives main contributi…
The latest results of CMS in the area of exotic quarkonium decays will be presented: observation of a peaking structure in $J/ψΦ$ mass spectrum in the decay $B^\pm \rightarrow J/ψΦK^\pm$, search for new bottomonium states in $Υ(1\mathrm{S})π^+π^-$ mass spectrum, measurement of prompt $J/ψ$ pair production.
Within the framework of nonrelativistic QCD (NRQCD) factorization, we calculate the next-to-leading-order (NLO) perturbative corrections to the radiative decay $Υ\to η_c(χ_{cJ})+γ$. Both the helicity amplitudes and the helicity decay widths are obtained. It is the first computation for the processes involving both bottomonium and charmonium at two-loop accuracy. By employing the Cheng-Wu theorem, we are able to convert most of complex-valued master integrals (MIs) into real-valued MIs, which makes the numerical integration much efficient. Our results indicate the $\mathcal{O}(α_s)$ corrections…
Motivated by very recent measurement of the radiative decays of $Υ(1S)$ to $χ_{c1}$ at Belle, we use the nonrelativistic QCD factorization theory and calculate the branching fractions of the radiative decays of bottomonium into S-wave and P-wave charmonium, i.e. $Υ(nS) \to η_c(nS)+γ$ and $Υ(nS)\to χ_{cJ}+γ$. We systematically studied the branching fractions of the radiative decays of bottomonium into charmonium. Compared to the previous calculation, we obtained the analytical expression for the decay widths and considered the color-octet contributions. For $Υ(nS) \to η_c(nS)+γ$, the relativist…
We study the mass splittings of $Q_1q_2\bar{Q}_3\bar{q}_4$ ($Q=c,b$, $q=u,d,s$) tetraquark states with chromomagnetic interactions between their quark components. Assuming that $X(4140)$ is the lowest $J^{PC}=1^{++}$ $cs\bar{c}\bar{s}$ tetraquark, we estimate the masses of the other tetraquark states. From the obtained masses and defined measure reflecting effective quark interactions, we find the following assignments for several exotic states: (1) both $X(3860)$ and the newly observed $Z_c(4100)$ seem to be $0^{++}$ $cn\bar{c}\bar{n}$ tetraquarks; (2) $Z_c(4200)$ is probably a $1^{+-}$ $cn\b…
New enhancements in the charmonium and bottomonium spectra observed since 2003 are very briefly reviewed. Special attention is paid to $χ_{c1}(3872)$ (formerly $X(3872)$) owing to its remarkable proximity to the $\bar{D}^{\star0}\!D^0$ threshold, which allows modelling as a quasibound axial-vector $c\bar{c}$ state with a large $\bar{D}^{\star0}\!D^0$ admixture. In contrast, the interpretation of many other charmonium-like and bottomonium-like states is still very controversial and some may not even correspond to genuine resonances. Accordingly, several entries in the PDG tables have been wildl…
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) and Institute of Modern Physics, Fudan University(复旦大学现代物理研究所);School of Mathematics and Physics, Kangwon National University(江原国立大学数理学院);Department of Physics, Sejong University(世宗大学物理系);College of Physics, Chengdu University of Technology(成都理工大学物理学院)