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Publications and source records attributed to CLEO Collaboration.
Using 281/pb of data recorded by the CLEO-c detector observing e+e- collisions at the psi(3770), corresponding to 1.8 million D Dbar pairs, the substructure of the decay D+ to pi+ pi- pi+ is investigated using the Dalitz plot technique. The results presented in this document are preliminary.
We examine e+e- to Ds- Ds*+ or Ds-* Ds+ collisions at 4170 MeV using the CLEO-c detector in order to measure the decay constant f_Ds+. We use the Ds+ to ell+ nu channel, where the ell+ designates either a mu+ or a tau+. Analyzing both modes simultaneously, we determine B(D_s^+ to mu+ nu)= (0.657 +- 0.090 +- 0.028)%, B(D_s^+ to tau+ nu)= (7.1 +- 1.4 +- 0.3)%, and extract f_Ds+ = 282 +- 16 +- 7 MeV. Combining with our previous determination of B(D+ to mu+ nu), we find that the ratio f_Ds+/f_D+ = 1.27 +- 0.12 +- 0.03. (All new results here are preliminary.) We compare with current theoretical estimates.
We present an improved measurement of the eta' meson energy spectrum in Upsilon(1S) decays, using 1.2 fb^{-1}} of data taken at the Upsilon(1S) center-of-mass energy with the CLEO III detector. We compare our results with models of eta' gluonic form factor that have been suggested to explain the unexpectedly large B to eta' X_s rate. Models based on perturbative QCD fail to fit the data for large eta' energies, showing that Standard Model strong interaction dynamics is not likely to provide an explanation for the large rate of high energy eta' observed in B decays.
We have studied the Cabibbo-suppressed decay mode D^0 into K^+ K^- pi^0 using a Dalitz plot technique and find the strong phase difference delta_D [defined as delta_(K*^- K^+) - delta_(K*^+ K^-)] = 332 degrees +- 8 degrees +- 11 degrees and relative amplitude r_D [defined as a_(K*^- K^+) / a_(K*^+ K^-)] = 0.52 +- 0.05 +- 0.04. This measurement indicates significant destructive interference between D^0 into K^+ (K^- pi^0)_K*^- and D^0 into K^- (K^+ pi^0)_K*^+ in the Dalitz plot region where these two modes overlap. This analysis uses 9.0 fb^(-1) of data collected at s^(1/2) of approximately 10.58 GeV with the CLEO III detector.
From e+e- collision data acquired with the CLEO-c detector at CESR, we search for the non-DDbar decays psi(3770) -> gamma chi_cJ, with chi_cJ reconstructed in four exclusive decays modes containing charged pions and kaons. We report the first observation of such decays for J=0 with a branching ratio of (0.73+-0.07+-0.06)%. The rates for different J are consistent with the expectations assuming psi(3770) is predominantly a 1^3D_1 state of charmonium, but only if relativistic corrections are applied.
From e+e- collision data acquired with the CLEO detector at CESR, we observe the non-D Dbar decay psi(3770)->gamma chi_c1 with a statistical significance of 6.6 standard deviations, using the two-photon cascades to J/psi and J/psi->l+l-. We determine sigma(e+e- -> psi(3770)) x BR(psi(3770)->gamma chi_c1) =(18.0 pm3.3 pm2.5) pb and branching fraction BR(psi(3770)->gamma chi_c1)=(2.8+-0.5+-0.4) x 10^-3. We set 90% C.L. upper limits for the transition to chi_c2 (chi_c0) : sigma x BR < 5.7 pb (< 282 pb) and BR < 0.9 x 10^-3 (<44 x 10^-3). We also determine Gamma(psi(3770)->gamma chi_c1)/Gamma(psi(3770)->pi+pi-J/psi) =1.5+-0.3+-0.3 (>1.0 at 90 % C.L.), which bears upon the interpretation of X(3872).
We test whether or not the tau lepton manifests the same couplings as the mu lepton by investigating the relative decay rates in purely leptonic D+ meson decays. Specifically, we place the first upper limit on the ratio R=Gamma(D+ -> tau+ nu)/Gamma(D+ -> mu+ nu). We use 281 inverse pb of data accumulated at the psi(3770) resonance with the CLEO-c detector, to determine B(D+ -> tau+ nu) < 2.1 x 10^(-3) at 90% confidence level (C. L.). The ratio of R to the Standard Model expectation of 2.65 then is <1.8 at 90% C. L., consistent with the prediction of lepton universality.
Using 420 pb^-1 of data collected on the Upsilon(5S) resonance with the CLEO III detector, we reconstruct B mesons in 25 exclusive decay channels to measure or set upper limits on the decay rate of Upsilon(5S) into B meson final states. We measure the inclusive B cross-section to be sigma(Y(5S)-->BB(X))=(0.176+-0.030+-0.016) nb and make the first measurements of the production rates of sigma(Y(5S)-->B*B*)=(0.131+-0.025+-0.014) nb and sigma(Y(5S)-->BB*)=(0.043+-0.016+-0.006) nb, respectively. We set 90% confidence level limits of sigma(Y(5S)-->B B-bar)<0.038 nb, sigma(Y(5S)-->B(*)B(*)(pi))<0.055 nb and sigma(Y(5S)-->BBpipi)<0.024 nb. We also extract the most precise value of the B_s* mass to date, M(B_s*)=(5411.7+-1.6+-0.6) MeV/c^2.
The spin-singlet P-wave state of charmonium, hc(1P1), has been observed in the decay psi(2S) -> pi0 hc followed by hc -> gamma etac. Inclusive and exclusive analyses of the M(hc) spectrum have been performed. Two complementary inclusive analyses select either a range of energies for the photon emitted in hc -> gamma etac or a range of values of M(etac). These analyses, consistent with one another within statistics, yield M(h_c) =[3524.9 +/- 0.7 (stat) +/- 0.4 (sys)]MeV/c^2 and a product of the branching ratios B_psi(psi(2S) -> pi0 hc) x B_h(hc -> gamma etac) = [3.5 +/- 1.0 (stat) +/- 0.7 (sys)] x 10^{-4}. When the etac is reconstructed in seven exclusive decay modes, 17.5 +/- 4.5 hc events are seen with an average mass M(hc) = [3523.6 +/- 0.9 (stat) +/- 0.5 (sys)] MeV/c^2, and B_psi x B_h = [5.3 +/- 1.5 (stat) +/- 1.0 (sys)] x 10^{-4}. Because the inclusive and exclusive data samples are largely independent they are combined to yield an overall mass M(hc) = [3524.4 +/- 0.6 (stat) +/- 0.4 (sys)]MeV/c^2 and product of branching ratios B_psi x B_h = [4.0 +/- 0.8 (stat) +/- 0.7 (sys)] x 10^{-4}. The hc mass implies a P-wave hyperfine splitting Delta M_{HF}(1P) \equiv M(1^3P)-M(1^1P_1) = [1.0 +/- 0.6 (stat) +/- 0.4 (sys)] MeV/c^2.
Using data acquired with the CLEO detector at the CESR e+e- collider at sqrt{s} = 3.773 GeV, we measure the cross section for the radiative return process e+e- --> gamma J/psi, J/psi --> mu+mu-, resulting in B(J/psi --> mu+mu-) x Gamma_ee(J/psi) = 0.3384 +- 0.0058 +- 0.0071 keV, Gamma_ee(J/psi) = 5.68 +- 0.11 +- 0.13 keV, and Gamma_tot(J/psi) = 95.5 +- 2.4 +- 2.4 keV, in which the errors are statistical and systematic, respectively. We also determine the ratio Gamma_ee[psi(2S)] / Gamma_ee(J/psi) = 0.45 +- 0.01 +- 0.02.
Using the current world's largest data sample of psi(3770) decays, we present results of a search for the non-DDbar decay psi(3770) -> KsKl. We find no signal, and obtain an upper limit of Sigma(psi(3770) -> KsKl) < 0.07 pb at 90% confidence level (CL). Our result tests a theoretical prediction for the upper bound on B(psi(3770) -> KsKl) based on a charmonia-mixing model.
Using a sample of 3.08 million psi(2S) decays collected at sqrt{s} = 3.686 GeV with the CLEO detector at the Cornell Electron Storage Ring, we have measured the branching fractions for psi(2S) decays to pseudoscalar pairs pi+pi-, K+K-, and KsKl. We obtain B(psi(2S) -> pi+pi-) < 2.1 x 10^{-5} (90% C.L.), B(psi(2S) -> K+K-) = (6.3 +- 0.6(stat) +- 0.3(syst)) x 10^{-5}, and B(psi(2S) -> KsKl) = (5.8 +- 0.8(stat) +- 0.4(syst)) x 10^{-5}. The branching fractions allow extraction of the relative phase Delta = (95 +- 15) degrees and strength ratio R = (2.5 +- 0.4) of the three-gluon and one-photon amplitudes for these modes.
We observe signals for the decays psi(3770)--> X J/psi from data acquired with the CLEO detector operating at the CESR e^+e^- collider with sqrt{s}=3773 MeV. We measure the following branching fractions B(psi(3770)--> XJ/psi) and significances: (189 +- 20 +- 20) x 10^-5 (11.6sigma) for X=pi^+pi^-, (80 +- 25 +- 16) x 10^-5 (3.4sigma) for X=pi^0pi^0, and (87 +- 33 +- 22) x 10^-5 (3.5sigma) for X=eta, where the errors are statistical and systematic, respectively. The radiative return process e^+e^- -->gamma psi(2S) populates the same event sample and is used to measure Gamma_{ee}[psi(2S)]=(2.54 +- 0.03 +- 0.11) keV.
Using data collected at the psi(3770) resonance with the CLEO-c detector at the Cornell e^+e^- storage ring, we present searches for 25 charmless decay modes of the psi(3770), mostly multibody final states. No evidence for charmless decays is found.
We describe a search for psi(3770) decay to two-body non-DDbar final states in e+e- data produced by the CESR collider and analyzed with the CLEO-c detector. Vector-pseudoscalar production of Rho0Pi0, Rho+Pi-, OmegaPi0, PhiPi0, RhoEta, OmegaEta, PhiEta, RhoEtaPrime, OmegaEtaPrime, PhiEtaPrime, Kstar0 K0bar, and Kstar+K- is studied along with that of BOnePi (BOne0Pi0 and BOne+Pi-) and Pi+Pi-Pi0. A statistically significant signal is found for PhiEta, at an excess cross section of (2.4 +- 0.6) pb [Gamma_{PhiEta} (psi(3770)) =(74 +- 16)Mev], and a suggestive suppression of Pi+Pi-Pi0 and RhoPi. We conclude with form factor determinations for OmegaPi0, RhoEta, and RhoEtaPrime.
Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the Bs meson in e+e- annihilation at the Upsilon(5S) resonance. We find 14 candidates consistent with Bs decays into final states with a J/psi or a Ds(*)-. The probability that we have observed a background fluctuation is less than 8x10e-10. We have established that at the energy of the Upsilon(5S) resonance Bs meson production proceeds predominantly through the creation of Bs*Bs* pairs. We find sigma(e+e- -> Bs*Bs*) = [0.11 (+0.04-0.03)(stat.)+/-0.02(syst.)] nb, and set the following limits: sigma(e+e- -> BsBs) / sigma(e+e- -> Bs*Bs*) < 0.16 and sigma(e+e- -> BsBs*) / sigma(e+e- -> Bs*Bs*) < 0.16 at the 90% confidence level. The mass of the Bs* meson is measured to be M(Bs*) = [5.414 +/- 0.001(stat.) +/- 0.003(syst.)] GeV.
We present the first experimental limits on high-q^2 contributions to charmless semileptonic B decays of the form expected from the Weak Annihilation (WA) decay mechanism. Such contributions could bias determinations of |Vub| from inclusive measurements of B-> X_u lnu. Using a wide range of models based on available theoretical input we set a limit of (Gamma_WA/Gamma_b->u) < 7.4% (90% confidence level) on the WA fraction, and assess the impact on previous inclusive determinations of |Vub|.
We have searched for the di-pion transition chi_b(2P) -> pi pi chi_b(1P) in the CLEO III sample of Upsilon(3S) decays in the exclusive decay chain: Upsilon(3S) -> gamma chi_b(2P), chi_b(2P) -> pi pi chi_b(1P), chi_b(1P) -> gamma Upsilon(1S), Upsilon(1S) -> lepton pairs. Our studies include both pi+ pi- and pi0 pi0, each analyzed both in fully reconstructed events and in events with one pion undetected. We show that the null hypothesis is not substantiated. Under reasonable assumptions, we find the partial decay width to be Gamma[chi_b(2P) -> pi pi chi_b(1P)] = (0.83 +/- 0.22 +/- 0.08 +/- 0.19) keV, with the uncertainties being statistical, internal CLEO systematics, and common systematics from outside sources.