S. Dobbs

Observation of the charged hadron Zc±(3900) and evidence for the neutral Zc0(3900) in e+e−→ππJ/ψ at s=4170MeV

Abstract Using 586 pb − 1 of e + e − annihilation data taken with the CLEO-c detector at s = 4170 MeV , the peak of the charmonium resonance ψ ( 4160 ) , we analyze the decay ψ ( 4160 ) → π + π − J / ψ , and report observation of the charged state Z c ± ( 3900 ) decaying into π ± J / ψ at a significance level of > 5 σ . We obtain M ( Z c ± ) = 3886 ± 4 ( stat ) ± 2 ( syst ) MeV and Γ ( Z c ± ) = 37 ± 4 ( stat ) ± 8 ( syst ) MeV , which are in good agreement with the results for this resonance obtained by the BES III and Belle Collaborations in the decay of the resonance Y(4260). We also present first evidence for the production of the neutral member of this isospin triplet, Z c 0 ( 3900 ) decaying into π 0 J / ψ at a 3.5σ significance level.

Model-independent determination of the strong-phase difference between D0 and D⊃̄0→KS,L0h+h- (h=π, K) and its impact on the measurement of the CKM angle γ/Φ3

We report the first determination of the relative strong-phase difference between D0→KS,L0K+K- and D 0→KS,L0K+K-. In addition, we present updated measurements of the relative strong-phase difference between D0→KS,L0π+π- and D 0→KS,L0π+π-. Both measurements exploit the quantum coherence between a pair of D0 and D 0 mesons produced from ψ(3770) decays. The strong-phase differences measured are important for determining the Cabibbo-Kobayashi-Maskawa angle γ/ϕ3 in B-→K-D˜0 decays, where D˜0 is a D0 or D 0 meson decaying to KS0h+h- (h=π, K), in a manner independent of the model assumed to describe the D0→KS0h+h- decay. Using our results, the uncertainty in γ/ϕ3 due to the error on the strong-phase difference is expected to be between 1.7° and 3.9° for an analysis using B-→K-D˜0, D˜0→KS0π+π- decays, and between 3.2° and 3.9° for an analysis based on B-→K-D˜0, D˜0→KS0K+K- decays. A measurement is also presented of the CP-odd fraction, F-, of the decay D0→KS0K+K- in the region of the ϕ→K+K- resonance. We find that in a region within 0.01  GeV2/c4 of the nominal ϕ mass squared F->0.91 at the 90% confidence level.

Improved measurements of D meson semileptonic decays to π and K mesons

Using the entire CLEO-c {psi}(3770){yields}DD event sample, corresponding to an integrated luminosity of 818 pb{sup -1} and approximately 5.4x10{sup 6} DD events, we present a study of the decays D{sup 0}{yields}{pi}{sup -}e{sup +}{nu}{sub e}, D{sup 0}{yields}K{sup -}e{sup +}{nu}{sub e}, D{sup +}{yields}{pi}{sup 0}e{sup +}{nu}{sub e}, and D{sup +}{yields}K{sup 0}e{sup +}{nu}{sub e}. Via a tagged analysis technique, in which one D is fully reconstructed in a hadronic mode, partial rates for semileptonic decays by the other D are measured in several q{sup 2} bins. We fit these rates using several form factor parametrizations and report the results, including form factor shape parameters and the branching fractions B(D{sup 0}{yields}{pi}{sup -}e{sup +}{nu}{sub e})=(0.288{+-}0.008{+-}0.003)%, B(D{sup 0}{yields}K{sup -}e{sup +}{nu}{sub e})=(3.50{+-}0.03{+-}0.04)%, B(D{sup +}{yields}{pi}{sup 0}e{sup +}{nu}{sub e})=(0.405{+-}0.016{+-}0.009)%, and B(D{sup +}{yields}K{sup 0}e{sup +}{nu}{sub e})=(8.83{+-}0.10{+-}0.20)%, where the first uncertainties are statistical and the second are systematic. Taking input from lattice quantum chromodynamics, we also find |V{sub cd}|=0.234{+-}0.007{+-}0.002{+-}0.025 and |V{sub cs}|=0.985{+-}0.009{+-}0.006{+-}0.103, where the third uncertainties are from lattice quantum chromodynamics.

Measurements of D meson decays to two pseudoscalar mesons

Using data collected on the {psi}(3770) resonance and near the D{sub s}*{sup {+-}D}{sub s}{sup {+-}}peak production energy by the CLEO-c detector, we study the decays of the possible D{yields}PP modes and report measurements of or upper limits on all branching fractions for Cabibbo-favored, singly Cabibbo-suppressed, and doubly Cabibbo-suppressed D{yields}PP decays except modes involving K{sub L}{sup 0} (and except D{sup 0{yields}}K{sup +{pi}-}). We normalize with respect to the Cabibbo-favored D modes, D{sup 0{yields}}K{sup -{pi}+}, D{sup +{yields}}K{sup -{pi}+{pi}+}, and D{sub s}{sup +{yields}}K{sup +}K{sub S}{sup 0}.

Measurement of the ηb(1S) mass and the branching fraction for Υ(3S)→γηb(1S)

We report evidence for the ground state of bottomonium, eta_b(1S), in the radiative decay Upsilon(3S) --> gamma eta_b in e^+e^- annihilation data taken with the CLEO III detector. Using 6 million Upsilon(3S) decays, and assuming Gamma(eta_b) = 10 MeV/c^2, we obtain B(Upsilon(3S) --> gamma eta_b) = (7.1 +- 1.8 +- 1.1) X 10^{-4}, where the first error is statistical and the second is systematic. The statistical significance is about 4 sigma. The mass is determined to be M(eta_b) = 9391.8 +- 6.6 +- 2.0 MeV/c^2, which corresponds to the hyperfine splitting Delta M_{hf}(1S)_b = 68.5 +- 6.6 +- 2.0 MeV/c^2. Using 9 million Upsilon(2S) decays, we place an upper limit on the corresponding Y(2S) decay, B(Y(2S) --> gamma eta_b) < 8.4 X 10^{-4} at 90 % confidence level.

Observation of the hc(1P) Using e+e- Collisions above the DD̄ Threshold

Using 586  pb(-1) of e+ e- collision data at E(c.m.) = 4170  MeV, produced at the Cornell Electron Storage Ring collider and collected with the CLEO-c detector, we observe the process e+ e- → π+ π- h(c)(1P). We measure its cross section to be 15.6±2.3±1.9±3.0  pb, where the third error is due to the external uncertainty on the branching fraction of ψ(2S) → π0 h(c)(1P), which we use for normalization. We also find evidence for e+ e- → ηh(c)(1P) at 4170 MeV at the 3σ level and see hints of a rise in the e+ e- → π+ π- h(c)(1P) cross section at 4260 MeV.

Updated measurement of the strong phase in D0→K+π- decay using quantum correlations in e+e-→D0D̄0 at CLEO

We analyze a sample of 3 million quantum-correlated D0 D0bar pairs from 818 pb^-1 of e+e- collision data collected with the CLEO-c detector at E_cm = 3.77 GeV, to give an updated measurement of \cos\delta and a first determination of \sin\delta, where \delta is the relative strong phase between doubly Cabibbo-suppressed D0 --> K+pi- and Cabibbo-favored D0bar --> K+pi- decay amplitudes. With no inputs from other experiments, we find \cos\delta = 0.81 +0.22+0.07 -0.18-0.05, \sin\delta = -0.01 +- 0.41 +- 0.04, and |\delta| = 10 +28+13 -53-0 degrees. By including external measurements of mixing parameters, we find alternative values of \cos\delta = 1.15 +0.19+0.00 -0.17-0.08, \sin\delta = 0.56 +0.32+0.21 -0.31-0.20, and \delta = (18 +11-17) degrees. Our results can be used to improve the world average uncertainty on the mixing parameter y by approximately 10%.

Dalitz plot analysis of Ds+→K+K-π+

We perform a Dalitz plot analysis of about 100,000 Ds+ decays to K+ K- pi+ and measure the complex amplitudes of the intermediate resonances which contribute to this decay mode. We also measure the relative branching fractions of Ds+ -->K+ K+ pi- and Ds+ -->K+ K+ K-. For this analysis we use a 384 fb-1 data sample, recorded by the BABAR detector at the PEP-II asymmetric-energy e+e- collider running at center-of-mass energies near 10.58 GeV.We perform a Dalitz plot analysis of about 100 000 Ds+ decays to K+K-π+ and measure the complex amplitudes of the intermediate resonances which contribute to this decay mode. We also measure the relative branching fractions of Ds+→K+K+π- and Ds+→K+K+K-. For this analysis we use a 384 fb-1 data sample, recorded by the BABAR detector at the PEP-II asymmetric-energy e+e- collider running at center-of-mass energies near 10.58 GeV.

Study of ψ(2S) decays to γpp̄, π0pp̄, and ηpp̄, and search for pp̄ threshold enhancements

The decays of {psi}(2S) into {gamma}pp, {pi}{sup 0}pp, and {eta}pp have been studied with the CLEO-c detector using a sample of 24.5x10{sup 6} {psi}(2S) events obtained from e{sup +}e{sup -} annihilations at {radical}(s)=3686 MeV. The data show evidence for the excitation of several N{sup *} resonances in p{pi}{sup 0} and p{eta} channels in {pi}{sup 0}pp and {eta}pp decays, and f{sub 2} states in {gamma}pp decay. Branching fractions for decays of {psi}(2S) to {gamma}pp, {pi}{sup 0}pp, and {eta}pp have been determined. No evidence for pp threshold enhancements was found in the reactions {psi}(2S){yields}Xpp, where X={gamma}, {pi}{sup 0}, {eta}. We do, however, find confirming evidence for a pp threshold enhancement in J/{psi}{yields}{gamma}pp as previously reported by BES.

Updated measurements of absolute

Utilizing the full CLEO-c data sample of 818 pb