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Register a new userEnergy scan of the $e^+e^- to h_b(nP)pi^+pi^-$ $(n=1,2)$ cross sections and evidence for $Upsilon(11020)$ decays into charged bottomonium-like states
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Using data collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider, we measure the energy dependence of the $e^+e^- to h_b(nP)pi^+pi^-$ $(n=1,2)$ cross sections from thresholds up to $11.02,$GeV. We find clear $Upsilon(10860)$ and $Upsilon(11020)$ peaks with little or no continuum contribution. We study the resonant substructure of the $Upsilon(11020) to h_b(nP)pi^+pi^-$ transitions and find evidence that they proceed entirely via the intermediate isovector states $Z_b(10610)$ and $Z_b(10650)$. The relative fraction of these states is loosely constrained by the current data: the hypothesis that only $Z_b(10610)$ is produced is excluded at the level of 3.3 standard deviations, while the hypothesis that only $Z_b(10650)$ is produced is not excluded at a significant level.
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We report new measurements of the total cross sections for $e^+e^-to Upsilon(n{rm S})pi^+pi^-$ ($n$ = 1, 2, 3) and $e^+e^-to bbar b$ from a high-luminosity fine scan of the region $sqrt{s} = 10.63$-$11.05$ GeV with the Belle detector. We observe that the $Upsilon(n{rm S})pi^+pi^-$ spectra have little or no non-resonant component and extract from them the masses and widths of $Upsilon(10860)$ and $Upsilon(11020)$ and their relative phase. We find $M_{10860}=(10891.1pm3.2^{+0.6}_{-1.7})$ MeV/$c^2$ and $Gamma_{10860}=(53.7^{+7.1}_{-5.6},^{+1.3}_{-5.4})$ MeV and report first measurements $M_{11020}=(10987.5^{+6.4}_{-2.5},^{+9.0}_{-2.1})$ MeV/$c^2$, $Gamma_{11020}=(61^{+9}_{-19},^{+2}_{-20})$ MeV, and $phi_{rm 11020}-phi_{rm 10860} = (-1.0pm0.4,^{+1.4}_{-0.1})$ rad.
We calculate the cross sections and final state distributions for the processes e^+ e^- --> Upsilon(1S) (pi^+ pi^-, K^+ K^-, eta pi^0) near the Upsilon(5S) resonance based on the tetraquark hypothesis. This framework is used to analyse the data on the Upsilon(1S) pi^+ pi^- and Upsilon(1S) K^+ K^- final states [K.F. Chen et al. (Belle Collaboration), Phys. Rev. Lett. 100, 112001 (2008); I. Adachi et al. (Belle Collaboration), arXiv:0808.2445], yielding good fits. Dimeson invariant mass spectra in these processes are shown to be dominated by the corresponding light scalar and tensor states. The resulting correlations among the cross sections are worked out. We also predict sigma(e^+ e^- --> Upsilon(1S) K^+ K^-)/sigma(e^+ e^- --> Upsilon(1S) K^0 Kbar^0) = 1/4. These features provide crucial tests of the tetraquark framework and can be searched for in the currently available and forthcoming data from the B factories.
We report a new measurement of the $e^+e^-toUpsilon(nS)pi^+pi^-$ ($n=1,2,3$) cross sections at energies from 10.52 to 11.02 GeV using data collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We observe a new structure in the energy dependence of the cross sections; if described by a Breit-Wigner function its mass and width are found to be $M=(10752.7pm5.9,^{+0.7}_{-1.1}),$MeV/$c^2$ and $Gamma=(35.5^{+17.6}_{-11.3},^{+3.9}_{-3.3}),$MeV, where the first error is statistical and the second is systematic. The global significance of the new structure including systematic uncertainty is 5.2 standard deviations. We also find evidence for the $e^+e^-toUpsilon(1S)pi^+pi^-$ process at the energy 10.52 GeV, which is below the $Bbar{B}$ threshold.
We study the processes $e^+ e^-to 2(pi^+pi^-)pi^0gamma$, $2(pi^+pi^-)etagamma$, $K^+ K^-pi^+pi^-pi^0gamma$ and $K^+ K^-pi^+pi^-etagamma$ with the hard photon radiated from the initial state. About 20000, 4300, 5500 and 375 fully reconstructed events, respectively, are selected from 232 fb$^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective $e^+ e^-$ center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct epem measurements, currently available only for the $etapi^+pi^-$ and $omegapi^+pi^-$ submodes of the $e^+ e^-to 2(pi^+pi^-)pi^0$ channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-toomega(782)pi^+pi^-$ and study the $omega(1420)$ and $omega(1650)$ resonances. In the charmonium region, we observe the $J/psi$ in all these final states and several intermediate states, as well as the $psi(2S)$ in some modes, and we measure the corresponding branching fractions.
We study the process e+e- -> pi+pi-pi+pi-gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb^-1 of data collected with the BABAR detector at SLAC, corresponding to approximately 260,000 signal events. We use these data to extract the non-radiative sigma(e+e- ->pi+pi-pi+pi-) cross section in the energy range from 0.6 to 4.5 Gev. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
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