117194771
Measurement of B(Lambda+(c) ---> p K- pi+)
The /\c->pKpi yield has been measured in a sample of two-jet continuum events containing a both an anticharm tag (Dbar) as well as an antiproton (e+e- -> Dbar pbar X), with the antiproton in the hemisphere opposite the Dbar. Under the hypothesis that such selection criteria tag e+e- -> Dbar pbar (/\c) X events, the /\c->pkpi branching fraction can be determined by measuring the pkpi yield in the same hemisphere as the antiprotons in our Dbar pbar X sample. Combining our results from three independent types of anticharm tags, we obtain B(/\c->pKpi)=(5.0+/-0.5+/-1.2)%
123152124
Preliminary measurements of shadowing at very low XBj
The ratio of cross sections for inelastic muon scattering on xenon and deuterium nuclei was measured at very low XBj (0.00002<XBj<0.25) for 0.01<Q2<60 (GeV/c)2. The data were taken at Fermilab experiment E665 with an average muon beam energy of 490 GeV incident on 1.1 meter long deuterium and xenon targets. Two largely independent analysis techniques gave statistically consistent results and show a smooth decrease in the ratio of the xenon‐to‐deuterium per–nucleon cross sections from ∼1 to ∼0.7 as XBj decreases from ∼0.1 to ∼0.003. In the XBj range 0.00002 to 0.003, the ratio remains roughly constant at ∼0.7.
42580412
Identification of High Transverse-Momentum Hadrons with a Ring-Imaging Cerenkov Counter
We have constructed and operated a large aperture ring-imaging Cerenkov counter in a high transverse-momentum experiment at Fermilab. We used multistep proportional chambers with a He/TEA photosensitive gas mixture to observe approximately 3.5 photons per relativistic particle. Hadron identification is obtained with good efficiency from threshold to 250 GeV/c.
119445846
Comparison of inclusive particle production in 14.6 GeV/c proton-nucleus collisions with simulation
Inclusive charged pion, kaon, proton, and deuteron production in 14.6 GeV/c proton-nucleus collisions measured by BNL experiment E802 is compared with results from the GEANT3, GEANT4, and FLUKA simulation packages. The FLUKA package is found to have the best overall agreement.
197497757
LATEST RESULTS FROM MINOS.
Among the goals of the MINOS experiment are the test of the {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillation and the search for sub-dominant {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillations. The former proceeds by a {nu}{sub {mu}} ''disappearance'' analysis while the latter would involve the ''appearance'' of {nu}{sub e} interactions in a predominantly {nu}{sub {mu}} beam. The disappearance of muon neutrinos is described by P({nu}{sub {mu}} {yields} {mu}{sub {mu}}) = 1 - sin{sup 2} 2{theta}{sub 23} sin{sup 2} (1.27 {Delta} m{sub 23}{sup 2} L/E) in the two-flavor approximation where {theta}{sub 23} is the angle between the second row and third column of the neutrino mixing matrix, {Delta}m{sub 23}{sup 2} = m{sub 2}{sup 2}-m{sub 3}{sup 2} (eV{sup 2}), L is the neutrino flight distance in km and E is the neutrino energy in GeV. A generic disappearance experiment compares a measured muon neutrino energy spectrum at a fixed baseline to the known energy spectrum of muon neutrino beam to extract the oscillation parameters sin{sup 2} 2{theta} which controls the overall magnitude of the disappearance and {Delta}m{sup 2} which controls the energy dependence.
14433479
Search for CP violation at CLEO
Abstract Recent results from CLEO on the search for CP violation in beauty and charm meson decays are reviewed.
18053247
Looking for Pure Rotational H2 Emission from Protoplanetary Disks
We report on a limited search for pure rotational molecular hydrogen emission associated with young, pre-main-sequence stars. We looked for H_2 v = 0, J = 3 → 1 and 4 → 2 emission in the mid-infrared using the Texas Echelon Cross Echelle Spectrograph at NASA's 3 m Infrared Telescope Facility. The high spectral and spatial resolutions of our observations lead to more stringent limits on narrow-line emission close to the source than previously achieved. One star, AB Aur, shows a possible (2 σ) H_2 detection, but further observations are required to make a confident statement. Our nondetections suggest that a significant fraction, perhaps all, of previously reported H_2 emission toward these objects could be extended on scales of 5" or more.
117282671
Extremely high velocity outflows.
Extremely high velocity (EHV) wings, with full widths of 72 to 140 km s −1 , are seen on the CO J=3→2 lines toward W3 IRS 5, GL 490, NGC 2071, W28 A2 (G05.89-0.39), GL 2591, S140, and Cepheus A. Observations of 12 CO and 13 CO J=3→2 and J=2→1 lines indicate that optical depth generally decreases with increasing velocity separation from the ambient cloud velocity. Maps of the extremely high velocity (|V−V 0 |≥20 km s −1 ) and the high-velocity (5≤|V−V 0 |≤20 km s −1 ) CO emission components show that the morphology of the two components is similar in W3 IRS 5 and W28 A2 but may be different in GL 2591, S 140, and Cepheus A
15000344
Starspot-Induced Radial Velocity Variability in LkCa 19
We describe a new radial velocity survey of T Tauri stars and present the first results. Our search is motivated by an interest in detecting massive young planets, as well as investigating the origin of the brown dwarf desert. As part of this survey, we discovered large-amplitude, periodic, radial velocity variations in the spectrum of the weak-line T Tauri star LkCa 19. Using line bisector analysis and a new simulation of the effect of starspots on the photometric and radial velocity variability of T Tauri stars, we show that our measured radial velocities for LkCa 19 are fully consistent with variations caused by the presence of large starspots on this rapidly rotating young star. These results illustrate the level of activity-induced radial velocity noise associated with at least some very young stars. This activity-induced noise will set lower limits on the mass of a companion detectable around LkCa 19 and similarly active young stars.
119474065
R=100,000 Mid-IR Spectroscopy of UCHII Regions: High Resolution is Worth it!
Ultracompact HII regions are signposts of massive star formation and their properties provide diagnostics for the characteristics of very young O stars embedded in molecular clouds. While radio observations have given us a good picture of the morphology of these regions, they have not provided clear information about the kinematics. Using high spectral resolution observations of the 12.8 micron [NeII] line, it has been possible for the first time to trace the internal kinematics of several ultracompact HII regions. We find that the motions in the cometary ultracompact HII regions MonR2 and G29.96-0.02 are highly organized. The velocity patterns are consistent with parabolic ionized flows along a neutral boundary layer.
55470700
MEDIUM RESOLUTION SPECTRAL LIBRARY OF LATE-TYPE STELLAR TEMPLATES IN NEAR-INFRARED BAND
We present medium resolution (R = 5000 6000) spectra in the near-infrared band, 1.4 1.8 µm, for template stars in G, K, and M types observed by the echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. The identification of lines is based on the spectra of Arcturus (K2 III) in the literature. We measured the equivalent of widths and compared our results to those of Meyer et al. (1998). We conclude that our spectral resolution (R = 6000) data can investigate more accurately the properties of lines in stellar spectra. The library of the template stellar spectra in ASCII format are available for download on the World Wide Web.