We report measurement of the cross section of $e^+e^-to pi^+pi^-psi(2S)$ between 4.0 and $5.5 {rm GeV}$, based on an analysis of initial state radiation events in a $980 rm fb^{-1}$ data sample recorded with the Belle detector. The properties of the
$Y(4360)$ and $Y(4660)$ states are determined. Fitting the mass spectrum of $pi^+pi^-psi(2S)$ with two coherent Breit-Wigner functions, we find two solutions with identical mass and width but different couplings to electron-positron pairs: $M_{Y(4360)} = (4347pm 6pm 3) {rm MeV}/c^2$, $Gamma_{Y(4360)} = (103pm 9pm 5) {rm MeV}$, $M_{Y(4660)} = (4652pm10pm 8) {rm MeV}/c^2$, $Gamma_{Y(4660)} = (68pm 11pm 1) rm MeV$; and ${cal{B}}[Y(4360)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4360)}^{e^+e^-} = (10.9pm 0.6pm 0.7) rm eV$ and ${cal{B}}[Y(4660)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4660)}^{e^+e^-} = (8.1pm 1.1pm 0.5) rm eV$ for one solution; or ${cal{B}}[Y(4360)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4360)}^{e^+e^-} = (9.2pm 0.6pm 0.6) rm eV$ and ${cal{B}}[Y(4660)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4660)}^{e^+e^-} = (2.0pm 0.3pm 0.2) rm eV$ for the other. Here, the first errors are statistical and the second systematic. Evidence for a charged charmoniumlike structure at $4.05 {rm GeV}/c^2$ is observed in the $pi^{pm}psi(2S)$ intermediate state in the $Y(4360)$ decays.
Using data samples of $102times10^6$ $Upsilon(1S)$ and $158times10^6$ $Upsilon(2S)$ events collected with the Belle detector, a first experimental search has been made for double-charmonium production in the exclusive decays $Upsilon(1S,2S)rightarrow
J/psi(psi)+X$, where $X=eta_c$, $chi_{cJ} (J=~0,~1,~2)$, $eta_c(2S)$, $X(3940)$, and $X(4160)$. No significant signal is observed in the spectra of the mass recoiling against the reconstructed $J/psi$ or $psi$ except for the evidence of $chi_{c1}$ production with a significance of $4.6sigma$ for $Upsilon(1S)rightarrow J/psi+chi_{c1}$. The measured branching fraction $BR(Upsilon(1S)rightarrow J/psi+chi_{c1})$ is $(3.90pm1.21(rm stat.)pm0.23 (rm syst.))times10^{-6}$. The $90%$ confidence level upper limits on the branching fractions of the other modes having a significance of less than $3sigma$ are determined. These results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach.
The $e^+e^- to pi^+ pi^- pi^0 chi_{bJ}$ ($J=0,~1,~2$) processes are studied using a 118~fb$^{-1}$ data sample collected at a center-of-mass energy of 10.867 GeV, in the $Upsilon(10860)$ energy range, with the Belle detector. The $pi^+ pi^- pi^0 chi_{
b1}$, $pi^+pi^-pi^0chi_{b2}$, $omegachi_{b1}$ signals and the evidence of $omegachi_{b2}$ are observed for the first time and the cross sections are measured. No significant $pi^+pi^-pi^0chi_{b0}$ or $omegachi_{b0}$ signal is observed and 90% confidence level upper limits on the cross sections for these two processes are obtained. In the $pi^+pi^-pi^0$ invariant mass spectrum, significant non-$omega$ signals are also observed. We search for the $X(3872)$-like state with a hidden $bbar{b}$ component (named $X_b$) decaying into $omega Upsilon(1S)$; no significant signal is observed with a mass between $10.55$ and $10.65$ GeV/$c^2$.
The cross sections of the processes $e^+ e^- to K^+ K^- J/psi$ and $K_S^0K_S^0J/psi$ are measured via initial state radiation at center-of-mass energies between the threshold and 6.0~GeV using a data sample of 980~fb$^{-1}$ collected with the Belle d
etector on or near the $Upsilon(nS)$ resonances, where $n=$1, 2, ..., 5. The cross sections for $e^+ e^- to K^+ K^- J/psi$ are at a few pb level and the average cross section for $e^+ e^- to K_S^0K_S^0J/psi$ is $1.8pm 0.6 (rm stat.)pm 0.3 (rm syst.)$~pb between 4.4 and 5.2~GeV. All of them are consistent with previously published results with improved precision. A search for resonant structures and associated intermediate states in the cross section of the process $e^+ e^- to K^+ K^- J/psi$ is performed.
Using data samples of 89 fb$^{-1}$, 703 fb$^{-1}$, and 121 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider at center-of-mass energies 10.52 GeV, 10.58 GeV, and 10.876 GeV, respectively, we study the exclusi
ve reactions $e^+e^- to omegapi^0$, $K^{ast}(892)bar{K}$, and $K_2^{ast}(1430)bar{K}$ (Charge-conjugate modes are included implicitly). Significant signals of $omegapi^0$, $K^{ast}(892)^0bar{K}^0$, and $K_2^{ast}(1430)^-K^+$ are observed for the first time at these energies, and the energy dependencies of the cross sections are presented. On the other hand, no significant excesses for $K^{ast}(892)^-K^+$ and $K_2^{ast}(1430)^0 bar{K}^0$ are found, and we set limits on the cross section ratios $R_{rm VP} = frac{sigma_B(e^+e^-to K^{ast}(892)^0bar K^0)} {sigma_B(e^+e^-to K^{ast}(892)^-K^+)}>$ 4.3, 20.0, and 5.4, and $R_{rm TP} = frac{sigma_B(e^+e^-to K_2^{ast}(1430)^0bar K^0)} {sigma_B(e^+e^-to K_2^{ast}(1430)^-K^+)}<$ 1.1, 0.4, and 0.6, for center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.876 GeV, respectively, at the 90% C.L.
Using samples of 102 million $Upsilon(1S)$ and 158 million $Upsilon(2S)$ events collected with the Belle detector, we study exclusive hadronic decays of these two bottomonium resonances to $ks K^+ pi^-$ and charge-conjugate (c.c.) states, $pi^+ pi^-
pi^0 pi^0$, and $pi^+ pi^- pi^0$, and to the two-body Vector-Pseudoscalar ($K^{ast}(892)^0bar{K}^0+ {rm c.c.}$, $K^{ast}(892)^-K^+ + {rm c.c.}$, $omegapi^0$, and $rhopi$) final states. For the first time, signals are observed in the modes $Upsilon(1S) to ks K^+ pi^- + {rm c.c.}$, $pi^+ pi^- pi^0 pi^0$, and $Upsilon(2S) to pi^+ pi^- pi^0 pi^0$, and evidence is found for the modes $Upsilon(1S)to pi^+ pi^- pi^0$, $K^{ast}(892)^0 bar{K}^0+ {rm c.c.}$, and $Upsilon(2S) to ks K^+ pi^- + {rm c.c.}$ Branching fractions are measured for all the processes, while 90% confidence level upper limits on the branching fractions are also set for the modes with a statistical significance of less than $3sigma$. The ratios of the branching fractions of $Upsilon(2S)$ and $Upsilon(1S)$ decays into the same final state are used to test a perturbative QCD prediction for OZI-suppressed bottomonium decays.
The cross section for $e^+ e^- to pi^+ pi^- J/psi$ between 3.8 GeV and 5.5 GeV is measured with a 967 fb$^{-1}$ data sample collected by the Belle detector at or near the $Upsilon(nS)$ ($n = 1, 2, ..., 5$) resonances. The Y(4260) state is observed, a
nd its resonance parameters are determined. In addition, an excess of $pi^+ pi^- J/psi$ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parameterization with properties that are consistent with the Y(4008) state that was previously reported by Belle. In a study of $Y(4260) to pi^+ pi^- J/psi$ decays, a structure is observed in the $M(pi^pmjpsi)$ mass spectrum with $5.2sigma$ significance, with mass $M=(3894.5pm 6.6pm 4.5) {rm MeV}/c^2$ and width $Gamma=(63pm 24pm 26)$ MeV/$c^{2}$, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmonium-like state.
Using samples of 102 million $Upsilon(1S)$ and 158 million $Upsilon(2S)$ events collected with the Belle detector, we study exclusive hadronic decays of these two bottomonium resonances to the three-body final states $phi K^+ K^-$, $omega pi^+ pi^-$
and $K^{ast 0}(892) K^- pi^+ $, and to the two-body Vector-Tensor ($phi f_2(1525)$, $omega f_2(1270)$, $rho a_2(1320)$ and $K^{ast 0}(892) bar{K}_2^{ast 0}(1430) $) and Axial-vector-Pseudoscalar ($K_1(1270)^+ K^-$, $K_1(1400)^+ K^- $ and $b_1(1235)^+ pi^- $) pairs. Signals are observed for the first time in the $Upsilon(1S) to phi K^+ K^-$, $omega pi^+ pi^-$, $K^{ast 0} K^- pi^+$, $K^{ast0} K_2^{ast 0}$ and $Upsilon(2S) to phi K^+ K^-$, $K^{ast 0} K^- pi^+$ decay modes. Branching fractions are determined for all the processes, while 90% confidence level upper limits are established on the branching fractions for the modes with a statistical significance less than $3sigma$. The ratios of the branching fractions of $Upsilon(2S)$ and $Upsilon(1S)$ decays into the same final state are used to test a perturbative QCD prediction for OZI suppressed bottomonium decays.
