Absolute branching fraction measurements for exclusive Ds semileptonic decays
Physical Review D - Particles, Fields, Gravitation and Cosmology 80:5 (2009)
Abstract:
We measure the absolute branching fractions of Ds semileptonic decays where the hadron in the final state is one of φ, η, η′, KS0, K 0, and f0, using 2.8×105 e+e-→DsDs decays collected in the CLEO-c detector at a center-of-mass energy close to 4170 MeV. We obtain B(Ds+→e+νe)=(2.29±0.37±0.11)%, B(Ds+→ηe+νe)= (2.48±0.29±0.13)%, B(Ds+→η′e+νe)=(0.91±0. 33±0.05)%, where the first uncertainties are statistical and the second are systematic. We also obtain B(Ds+→K0e+νe)=(0.37±0.10±0. 02)%, and B(Ds+→K0e+νe)=(0.18±0.07±0.01)%, which are the first measurements of Cabibbo suppressed exclusive Ds semileptonic decays, and, B(Ds+→f0e+νe)×B(f0→π+π-)=(0.13±0.04±0.01) %. This is the first absolute product branching fraction determination for a semileptonic decay including a scalar meson in the final state. © 2009 The American Physical Society.Evidence for decays of hc to multipion final states
Physical Review D - Particles, Fields, Gravitation and Cosmology 80:5 (2009)
Abstract:
Using a sample of 2.59×107 ψ(2S) decays collected by the CLEO-c detector, we present results of a search for the decay chain ψ(2S)→π0hc, hc→n(π+π-)π0, n=1, 2, 3. We observe no significant signals for n=1 and n=3 and set upper limits for the corresponding decay rates. First evidence for the decay hc→π+π-π+π-π0 is presented, and a product branching fraction of B(ψ(2S)→hcπ0) ×B(hc→2(π+π-)π0)=1.88-0.45-0.30+0.48+0.47×10-5 is measured. This result implies that hc→hadrons and hc→γηc have comparable rates, in agreement with expectations. © 2009 The American Physical Society.Galaxy Zoo: Exploring the Motivations of Citizen Science Volunteers
ArXiv 0909.2925 (2009)
Abstract:
The Galaxy Zoo citizen science website invites anyone with an Internet connection to participate in research by classifying galaxies from the Sloan Digital Sky Survey. As of April 2009, more than 200,000 volunteers had made more than 100 million galaxy classifications. In this paper, we present results of a pilot study into the motivations and demographics of Galaxy Zoo volunteers, and define a technique to determine motivations from free responses that can be used in larger multiple-choice surveys with similar populations. Our categories form the basis for a future survey, with the goal of determining the prevalence of each motivation.Probing the behaviour of the X-ray binary Cygnus X-3 with very-long-baseline radio interferometry
(2009)
'Disc-jet' coupling in black hole X-ray binaries and active galactic nuclei
(2009)