4,163 research outputs found
Heavy Quarkonium
I review heavy quarkonium physics in view of recent experimental results. In
particular, I discuss new results on spin singlet states, photon and hadronic
transitions, D-states and discovery of yet unexplained narrow X(3872) state.Comment: 15 pages, 16 figures. 2nd version: minor changes in references and
text. Invited talk presented at the 21st International Symposium On Lepton
And Photon Interactions At High Energies (LP03) 11-16 August 2003, Batavia,
Illinoi
Survival before annihilation in Psi-prime decays
We extend the simple scenario for decays suggested a few years ago.
The pair in the does not annihilate directly into three
gluons but rather survives before annihilating. An interesting prediction is
that a large fraction of all decays could originate from the channel which we urge experimentalists to identify. Our model
solves the problem of the apparent hadronic excess in decays as well as
the puzzle since, in our view, the two-body decays of the are
naturally of electromagnetic origin. Further tests of this picture are
proposed, e.g. .Comment: 6 pages, no figur
Measurements of Branching Fractions for Electromagnetic Transitions Involving the χ_{bJ}(1P) States
Using 9.32, 5.88 million Upsilon(2S,3S) decays taken with the CLEO-III detector, we obtain five product branching fractions for the exclusive processes Upsilon(2S) =\u3e gamma chi_{b0,1,2}(1P) =\u3e gamma gamma Upsilon(1S) and Upsilon(3S) =\u3e gamma chi_{b1,2}(1P) =\u3e gamma gamma Upsilon(1S). We observe the transition chi_{b0}(1P) =\u3e gamma Upsilon(1S) for the first time. Using the known branching fractions for B[Upsilon(2S) =\u3e gamma chi_{bJ}(1P)], we extract values for B[chi_{bJ}(1P) =\u3e gamma Upsilon(1S)] for J=0, 1, 2. In turn, these values can be used to unfold the Upsilon(3S) product branching fractions to obtain values for B[Upsilon(3S) =\u3e gamma chi_{b1,2}(1P) for the first time individually. Comparison of these with each other and with the branching fraction B[Upsilon(3S) =\u3e gamma chi_{b0}] previously measured by CLEO provides tests of relativistic corrections to electric dipole matrix elements
Analysis of the Decay D0 → K0Sπ0π0
We present the results of a Dalitz plot analysis of D^0 to K^0_S pi^0 pi^0 using the CLEO-c data set of 818 inverse pico-barns of e^+ e^- collisions accumulated at sqrt{s} = 3.77 GeV. This corresponds to three million D^0 D^0-bar pairs from which we select 1,259 tagged candidates with a background of 7.5 +- 0.9 percent. Several models have been explored, all of which include the K^*(892), K^*_2(1430), K^*(1680), the f_0(980), and the sigma(500). We find that the combined pi^0 pi^0 S-wave contribution to our preferred fit is (28.9 +- 6.3 +- 3.1)% of the total decay rate while D^0 to K^*(892)^0 pi^0 contributes (65.6 +- 5.3 +- 2.5)%. Using three tag modes and correcting for quantum correlations we measure the D^0 to K^0_S pi^0 pi^0 branching fraction to be (1.059 +- 0.038 +- 0.061)%
Observation of the Dalitz Decay Ds*+ → Ds*+ e+e-
Using 586 \textrm{pb}^{-1} of e^{+}e^{-} collision data acquired at \sqrt{s}=4.170 GeV with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-} with a significance of 5.3 \sigma. The ratio of branching fractions \calB(D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-}) / \calB(D_{s}^{*+} \to D_{s}^{+} \gamma) is measured to be [ 0.72^{+0.15}_{-0.13} (\textrm{stat}) \pm 0.10 (\textrm{syst})]%, which is consistent with theoretical expectations
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