We have measured the charge asymmetry in like-sign dilepton yields from B^0 B^0-bar meson decays using the CLEO detector at the Cornell Electron Storage Ring. We find a_ll = [N(l+l+) - N(l-l-)]/[N(l+l+) + N[l-l-)] = +0.013 +/- 0.050 +/- 0.005 . We combine this result with a previous, independent measurement and obtain Re(epsilon_B)/(1+|epsilon_B|^2) = +0.0035 +/- 0.0103 +/- 0.0015 (uncertainties are statistical and systematic, respectively) for the CP impurity parameter, epsilon_B.
CONST(NAME=EPSILON) is CP impurity parameter.
Using a sample of 3.3 million Upsilon(4S) -> BBbar events collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR), we measure the branching fraction for B -> rho l nu, |V_ub|, and the partial rate (Delta Gamma) in three bins of q^2 = (p_B-p_rho)^2. We find B(B^0 -> rho^- l^+ nu)=(2.69 +- 0.41^+0.35_-0.40 +- 0.50) 10^-4, |V_ub|=(3.23 +- 0.24^+0.23_-0.26 +- 0.58) 10^-3, Delta Gamma (0 < q^2 < 7 GeV^2/c^4) =(7.6 +- 3.0 ^+0.9_-1.2 +- 3.0) 10^-2 ns^-1, Delta Gamma (7 < q^2 < 14 GeV^2/c^4) =(4.8 +- 2.9 ^+0.7_-0.8 +- 0.7) 10^-2 ns^-1, and Delta Gamma (14 < q^2 < 21 GeV^2/c^4) = (7.1 +- 2.1^+0.9_-1.1 +- 0.6)10^-2 ns^-1. The quoted errors are statistical, systematic, and theoretical. The method is sensitive primarily to B -> rho l nu decays with leptons in the energy range above 2.3 GeV. Averaging with the previously published CLEO results, we obtain B(B^0 -> rho^- l^+ nu) = (2.57 +- 0.29^+0.33_-0.46 +- 0.41) 10^-4 and |V_{ub}| = (3.25 +- 0.14 ^+0.21_-0.29 +- 0.55) 10^-3.
VCB is the V-CKM (Cabibbo-Kobayashi-Maskawa) mixing matrix element. LEPTON+- stands for E+- or MU+-.
A study of charm fragmentation into $D_s^{*+}$ and $D_s^+$ in $e^+e^-$ annihilations at $\sqrt{s}$=10.5 GeV is presented. This study using $4.72 \pm 0.05$ fb$^{-1}$ of CLEO II data reports measurements of the cross-sections $\sigma(D_s^{*+})$ and $\sigma(D_s^+)$ in momentum regions above $x=0.44$, where $x$ is the $D_s$ momentum divided by the maximum kinematically allowed $D_s$ momentum. The $D_s$ vector to vector plus pseudoscalar production ratio is measured to be $P_V(x(D_s^+)>0.44)=0.44\pm0.04$
D/S*+ cross sections in regions of X(D/S*+). BR1 = BR(D/S*+ --> D/S+ GAMMA) * BR(D/S+ --> PHI PI+) * BR(PHI --> K+ K-).
D/S+ cross sections in regions of X(D/S+). BR2 = BR(D/S+ --> PHI PI+) * BR(PHI --> K+ K-).
D/S*+ cross sections in regions of X/D/S+. In effect this is the secondary D/S+ cross section. BR2 = BR(D/S+ --> PHI PI+) * BR(PHI --> K+ K-).
Using the CLEO detector at the Cornell $e~+e~-$ storage ring, CESR, we study the two-photon production of $\Lambda \overline{\Lambda}$, making the first observation of $\gamma \gamma \to \Lambda \overline{\Lambda}$. We present the cross-section for $ \gamma \gamma \to \Lambda \overline{\Lambda}$ as a function of the $\gamma \gamma$ center of mass energy and compare it to that predicted by the quark-diquark model.
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Using the CLEO~II detector, we have measured the differential cross sections for exclusive two-photon production of light pseudoscalar mesons $\pi^0$, $\eta$, and $\eta^{\prime}$. From our measurements we have obtained the form factors associated with the electromagnetic transitions $\gamma^*\gamma$ $\to$ meson. We have measured these form factors in the momentum transfer ranges from 1.5 to 9, 20, and 30 GeV$^2$ for $\pi^0$, $\eta$, and $\eta^{\prime}$, respectively, and have made comparisons to various theoretical predictions.
The results of PI0 --> GAMMA GAMMA analysis assuming Br(PI0-->2GAMMA)=0.99.
The results of ETA --> GAMMA GAMMA analysis assuming Br(ETA-->2GAMMA)=0.39.
The results of ETA --> 3PI0 analysis assuming Br(ETA-->3PI0)*Br(PI0-->2GAM MA)**3 = 0.31.
Using the CLEO-II detector, we have studied the exclusive two-photon production of the light pseudoscalar mesons in a single tagged mode. We report on a preliminary measurement of the $\pi~0$, $\eta$ and $\eta~{\prime}$ electromagnetic form factors in the $Q~2$ region from 2 ${\rm (GeV/c)}~2$ to 20 ${\rm (GeV/c)}~2$.}
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The CLEO II detector is used to search for the production of χc2 states in two-photon interactions. We use the signature χc2→γJ/ψ→γl+l− with l=e,μ. Using 1.49 fb−1 of data taken with beam energies near 5.29 GeV, the two-photon width of the χc2 is determined to be Γ(χc2→γγ)=1.08±0.30(stat)±0.26(syst) keV, in agreement with predictions from perturbative QCD.
Results below were obtained usign J/psi from-factors in the two photon propogators, and assumes that only transversely polarized photons are significant inthe production of the CHI/C2(1P) state.
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We have observed five new decay modes of the charmed baryon Λc+ using data collected with the CLEO II detector. Four decay modes, Λc+→pK¯0η, Ληπ+, Σ+η, and Σ*+η, are first observations of final states with an η meson, while the fifth mode, Λc+→ΛK¯0K+, requires the creation of an ss¯ quark pair. We measure the branching fractions of these modes relative to Λc+→pK−π+ to be 0.25±0.04±0.04, 0.35±0.05±0.06, 0.11±0.03±0.02, 0.17±0.04±0.03, and 0.12±0.02±0.02, respectively.
Integrated luminosity of 3.25 fb-1 have used, which corresponds to about 4 million C CBAR events.. Here X=P(LAMBDA/C)/sqrt(Ebeam**2-M(LAMBDA/C)**2).
Integrated luminosity of 3.25 fb-1 have used, which corresponds to about 4 million C CBAR events.. Here X=P(LAMBDA/C)/sqrt(Ebeam**2-M(LAMBDA/C)**2).
Integrated luminosity of 3.25 fb-1 have used, which corresponds to about 4 million C CBAR events.. Here X=P(LAMBDA/C)/sqrt(Ebeam**2-M(LAMBDA/C)**2).
We have measured the B0B¯0 mixing probability, χd, using a sample of 965 000 BB¯ pairs from Υ(4S) decays. Counting dilepton events, we find χd=0.157±0.016±0.018−0.021+0.028. Using tagged B0 events, we find χd=0.149±0.023±0.019±0.010. The first (second) error is statistical (systematic). The third error reflects a ±15% uncertainty in the assumption, made in both cases, that charged and neutral B pairs contribute equally to dilepton events. We also obtain a limit on the CP impurity in the Bd0 system, ‖Re(εB0)‖<0.045 at 90% C.L.
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Mixing parameter from counting dilepton events. CONST(N=MIXING PARAM) = 1/(1 - LAMBDA(C,N)) * (N(2LEPTON+) + N(2LEPTON-))/(N(LEPTON+,LEPTON-) + N(2LEPTON+) + N(2LEPTON-)). LAMBDA(C,N) is the fraction of dilepton events coming from B+B- decays, LAMBDA(C,N) = f(B+)*Br(B+)**2/(f(B+)*Br(B+)**2 + f(B0)*Br(B0)**2), where f(B+),f(B0) are the productiron fractions of the charged and neutral B's at the UPSI(4S), and Br(B+), Br(B0) are the semileptonic brancing fractions.
Mixing parameter from tagged B0 events.
We have used the momentum spectrum of leptons produced in semileptonic B-meson decays to set a 90%-confidence-level upper limit on Γ(b→ulν)Γ(b→clν) of 4%. We also measure the semileptonic branching fractions of the B meson to be (12.0±0.7±0.5)% for electrons and (10.8±0.6±1.0)% for muons.
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