Updated search for the flavor-changing neutral-current decay D0→μ⊃+μ⊃- in pp̄ collisions at √s=1.96 TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:9 (2010)
Abstract:
We report on a search for the flavor-changing neutral-current decay D0→μ⊃+μ⊃- in pp̄ collisions at √s=1.96TeV using 360pb⊃-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. A displaced vertex trigger selects long-lived D0 candidates in the μ⊃+μ⊃-, π⊃+π⊃-, and K⊃-π⊃+ decay modes. We use the Cabibbo-favored D0→K⊃- π⊃+ channel to optimize the selection criteria in an unbiased manner, and the kinematically similar D0→π⊃+π⊃- channel for normalization. We set an upper limit on the branching fraction B(D0→μ⊃+μ⊃-)<2.1×10⊃-7(3.0×10⊃-7) at the 90% (95%) confidence level. © 2010 The American Physical Society.Galaxy Zoo Supernovae
ArXiv 1011.2199 (2010)
Abstract:
This paper presents the first results from a new citizen science project: Galaxy Zoo Supernovae. This proof of concept project uses members of the public to identify supernova candidates from the latest generation of wide-field imaging transient surveys. We describe the Galaxy Zoo Supernovae operations and scoring model, and demonstrate the effectiveness of this novel method using imaging data and transients from the Palomar Transient Factory (PTF). We examine the results collected over the period April-July 2010, during which nearly 14,000 supernova candidates from PTF were classified by more than 2,500 individuals within a few hours of data collection. We compare the transients selected by the citizen scientists to those identified by experienced PTF scanners, and find the agreement to be remarkable - Galaxy Zoo Supernovae performs comparably to the PTF scanners, and identified as transients 93% of the ~130 spectroscopically confirmed SNe that PTF located during the trial period (with no false positive identifications). Further analysis shows that only a small fraction of the lowest signal-to-noise SN detections (r > 19.5) are given low scores: Galaxy Zoo Supernovae correctly identifies all SNe with > 8{\sigma} detections in the PTF imaging data. The Galaxy Zoo Supernovae project has direct applicability to future transient searches such as the Large Synoptic Survey Telescope, by both rapidly identifying candidate transient events, and via the training and improvement of existing machine classifier algorithms.Search for R-parity violating decays of sneutrinos to eμ, μτ, and eτ pairs in pp collisions at square root s = 1.96 TeV.
Phys Rev Lett 105:19 (2010) 191801
Abstract:
We present a search for supersymmetric neutrino ν production using the Tevatron pp collision data collected with the CDF II detector and corresponding to an integrated luminosity of 1 fb-1. We focus on the scenarios predicted by the R-parity violating (RPV) supersymmetric models in which sneutrinos decay to two charged leptons of different flavor. With the data consistent with the standard model expectations, we set upper limits on σ(pp→ν)×BR(ν→eμ,μτ,eτ) and use these results to constrain the RPV couplings as a function of the sneutrino mass.Study of ψ(2S) decays to γpp̄, π0pp̄, and ηpp̄, and search for pp̄ threshold enhancements
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:9 (2010)
Abstract:
The decays of ψ(2S) into γpp̄, π0pp̄, and ηpp̄ have been studied with the CLEO-c detector using a sample of 24.5×106 ψ(2S) events obtained from e⊃+e⊃- annihilations at √s=3686MeV. The data show evidence for the excitation of several N⊃* resonances in pπ0 and pη channels in π0pp̄ and ηpp̄ decays, and f2 states in γpp̄ decay. Branching fractions for decays of ψ(2S) to γpp̄, π0pp̄, and ηpp̄ have been determined. No evidence for pp̄ threshold enhancements was found in the reactions ψ(2S)→Xpp̄, where X=γ, π0, η. We do, however, find confirming evidence for a pp̄ threshold enhancement in J/ψ→γpp̄ as previously reported by BES. © 2010 The American Physical Society.The detection of a population of submillimeter-bright, strongly lensed galaxies.
Science 330:6005 (2010) 800-804