Study of Charmless Hadronic B Meson Decays to Pseudoscalar-Vector Final States

We report results of searches for charmless hadronic B meson decays to pseudoscalar(pi^+-,K^+-,Pi^0 or Ks^0)-vector(Rho, K* or Omega) final states. Using 9.7 million BBbar pairs collected with the CLEO detector, we report first observation of B^- --> Pi^-Rho^0, B^0 --> Pi^+-Rho^-+ and B^- --> Pi^-Omega, which are expected to be dominated by hadronic b --> u transitions. The measured branching fractions are (10.4+3.3-3.4+-2.1)x10^-6, (27.6+8.4-7.4+-4.2)x10^-6 and (11.3+3.3-2.9+-1.4)x10^-6, respectively. Branching fraction upper limits are set for all the other decay modes investigated.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

SOD1 and Amyotrophic Lateral Sclerosis: Mutations and Oligomerization

There are about 100 single point mutations of copper, zinc superoxide dismutase 1 (SOD1) which are reported (http://alsod.iop.kcl.ac.uk/Als/index.aspx) to be related to the familial form (fALS) of amyotrophic lateral sclerosis (ALS). These mutations are spread all over the protein. It is well documented that fALS produces protein aggregates in the motor neurons of fALS patients, which have been found to be associated to mitochondria. We selected eleven SOD1 mutants, most of them reported as pathological, and characterized them investigating their propensity to aggregation using different techniques, from circular dichroism spectra to ThT-binding fluorescence, size-exclusion chromatography and light scattering spectroscopy. We show here that these eleven SOD1 mutants, only when they are in the metal-free form, undergo the same general mechanism of oligomerization as found for the WT metal-free protein. The rates of oligomerization are different but eventually they give rise to the same type of soluble oligomeric species. These oligomers are formed through oxidation of the two free cysteines of SOD1 (6 and 111) and stabilized by hydrogen bonds, between beta strands, thus forming amyloid-like structures. SOD1 enters the mitochondria as demetallated and mitochondria are loci where oxidative stress may easily occur. The soluble oligomeric species, formed by the apo form of both WT SOD1 and its mutants through an oxidative process, might represent the precursor toxic species, whose existence would also suggest a common mechanism for ALS and fALS. The mechanism here proposed for SOD1 mutant oligomerization is absolutely general and it provides a common unique picture for the behaviors of the many SOD1 mutants, of different nature and distributed all over the protein

Measurement of the B0 and B+ meson masses from B0 -> psi(') K_S and B+ -> psi(') K+ decays

Using 9.6 million B meson pairs collected with the CLEO detector, we have fully reconstructed 135 B0 -> psi(') K_S and 526 B+ -> psi(') K+ candidates with very low background. We fitted the psi(')K invariant mass distributions of these B meson candidates and measured the masses of the neutral and charged B mesons to be M(B0)=5279.1+-0.7[stat]+-0.3[syst] MeV/c^2 and M(B+)=5279.1+-0.4[stat]+-0.4[syst] MeV/c^2. The precision is a significant improvement over previous measurements.Comment: 2 typographic errors corrected; 11 pages, 2 figures; also available through http://www.lns.cornell.edu/public/CLNS/CLEO.htm

First Observation of the Σc∗+\Sigma_{c}^{*+} Baryon and a New Measurement of the Σc+\Sigma_{c}^{+} Mass

Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the $\Sigma_c^{*+}$ charmed baryon, and an updated measurement of the mass of the $\Sigma_c^+$ baryon. We find $M(\Sigma_c^{*+})-M(\Lambda_c^+)$= 231.0 +- 1.1 +- 2.0 MeV, and $M(\Sigma_c^{+})-M(\Lambda_c^+)$= 166.4 +- 0.2 +- 0.3 MeV, where the errors are statistical and systematic respectively.Comment: 8 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Update of the Search for the Neutrinoless Decay τ→μγ\tau\to \mu\gamma

We present an update of the search for the lepton family number violating decay $\tau \to \mu\gamma$ using a complete CLEO II data sample of 12.6 million $\tau^+\tau^-$ pairs. No evidence of a signal has been found and the corresponding upper limit is \BR(\tau \to \mu\gamma) < 1.0 \times 10^{-6} at 90% CL, significantly smaller than previous limits. All quoted results are preliminary.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Measurements of the Mass, total Width and Two-Photon Partila Width of the ηc\eta_{c} Meson

Using 13.4 $fb^{-1}$ of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudo-scalar charmonium in the decay $\eta_c$ -> $K_S K^{\mp} \pi^{\pm}$. We have measured the $\eta_c$ mass to be (2980.4 +- 2.3 (stat) +- 0.6 (sys)) MeV and its full width as (27.0 +- 5.8 (stat) +- 1.4 (sys)) MeV. We have determined the two-photon partial width of the $\eta_c$ meson to be (7.6 +- 0.8 (stat) +- 0.4 (sys) +- 2.3 (br)) keV, with the last uncertainty associated with the decay branching fraction.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Study of exclusive two-body B0 meson decays to charmonium

We present a study of three B0 decay modes useful for time-dependent CP asymmetry measurements. From a sample of 9.7 million B meson pairs collected with the CLEO detector, we have reconstructed B0 -> J/psi K0S, B0 -> chi_c1 K0S, and B0 -> J/psi pi0 decays. The latter two decay modes have been observed for the first time. We describe a K0S -> pi0 pi0 detection technique and its application to the reconstruction of the decay B0 -> J/psi K0S. Combining the results obtained using K0S -> pi+ pi- and K0S -> pi0 pi0 decays, we determine Br(B0 -> J/psi K0) = (9.5 +- 0.8 +- 0.6)*10^-4, where the first uncertainty is statistical and the second one is systematic. We also obtain Br(B0 -> chi_c1 K0)= (3.9 +1.9/-1.3 +- 0.4)*10^-4 and Br(B0 -> J/psi pi0) = (2.5 +1.1/-0.9 +- 0.2)*10^-5.Comment: 11 pages, 2 figures, submitted to Phys. Rev.

Measurement of Charge Asymmetries in Charmless Hadronic in B Meson Decays

We search for CP-violating asymmetries (Acp) in the B meson decays to K+- pi-+, K+- pi0, Ks pi+-, K+- eta', and omega pi+-. Using 9.66 million Upsilon(4S) decays collected with the CLEO detector, the statistical precision on Acp is in the range of \pm 0.12 to \pm 0.25 depending on decay mode. While CP-violating asymmetries of up to \pm 0.5 are possible within the Standard Model, the measured asymmetries are consistent with zero in all five decay modes studied.Comment: 10 pages, 3 figure

Study of Exclusive Radiative B Meson Decays

We have investigated exclusive, radiative B meson decays to charmless mesons (\rho, \omega, \phi, K^*(892), K^*_2(1430)) in 9.7\times 10^6 BBbar decays accumulated with the CLEO detector. The B -> K^*(892)\gamma branching fractions are determined to be Br(B^0 -> K^{*0}(892)\gamma) = (4.55 +0.72-0.68 +-0.34)\times 10^-5 and Br(B^+ -> K^{*+}(892)\gamma) = (3.76 +0.89-0.83 +-0.28)\times 10^-5. We have searched for CP asymmetry in B -> K^*(892)\gamma decays and measure Acp = +0.08 +-0.13 +-0.03. We also report the first observation of the decay B -> K^*_2(1430)\gamma with a branching fraction of (1.66 +0.59-0.53 +-0.13)\times 10^-5 and determine $Br(B -> K^*_2(1430)\gamma)/Br(B -> K^*(892)\gamma) = 0.39 +0.15-0.13 consistent with only one of two available theoretical models. No significant evidence for the decays B -> \rho\gamma and B^0 -> \omega\gamma is found and we limit Br(B -> (\rho/\omega)\gamma)/Br(B -> K^{*}(892)\gamma) < 0.32 at 90% CL. We also find no evidence for the exotic decay B^0 -> \phi\gamma.Comment: 12 pages, 3 figures, submitted to Phys. Rev. Letter

Large Scale Problems in Practice: The effect of dimensionality on the interaction among variables

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This article performs a study on correlation between pairs of variables in dependence on the problem dimensionality. Two tests, based on Pearson and Spearman coefficients, have been designed and used in this work. In total, $86$ test problems ranging between 10 and 1000 variables have been studied. If the most commonly used experimental conditions are used, the correlation between pairs of variables appears, from the perspective of the search algorithm, to consistently decrease. This effect is not due to the fact that the dimensionality modifies the nature of the problem but is a consequence of the experimental conditions: the computational feasibility of the experiments imposes an extremely shallow search in case of high dimensions. An exponential increase of budget and population with the dimensionality is still practically impossible. Nonetheless, since real-world application may require that large scale problems are tackled despite of the limited budget, an algorithm can quickly improve upon initial guesses if it integrates the knowledge that an apparent weak correlation between pairs of variables occurs, regardless the nature of the problem