114 research outputs found
V618 Sgr: Galactic eclipsing symbiotic nova detected in repeated outbursts
V618 Sgr was previously classified as an R CrB-type variable and later as a
possible symbiotic star. Our study aims to analyse the nature of this target,
which is currently undergoing significant brightening in properties similar to
those of known symbiotic novae. We analyse literature information, photometric
observations, and 35 new optical spectra. Our findings strongly suggest that
V618 Sgr is an eclipsing symbiotic nova currently in outburst. Additionally,
since the star has demonstrated at least two similar brightenings in the past,
we propose that V618 Sgr could be the first known galactic symbiotic nova
observed in repeated outbursts of this type and may host a relatively massive
white dwarf.Comment: 6 pages, 6 figures, 1 table; accepted in MNRA
New measurement of exotic decay of Ac by C emission
The branching ratio of Ac decay by emission of C was remeasured under improved experimental conditions by using a radioactive source produced at the ISOLDE mass-separator at CERN and a nuclear track detector technique. The result, B=, is consistent with the anomalously high value obtained in the 1993 experiment thus confirming the importance of nuclear structure effects in this exotic decay
Design and Implementation of the New D0 Level-1 Calorimeter Trigger
Increasing luminosity at the Fermilab Tevatron collider has led the D0
collaboration to make improvements to its detector beyond those already in
place for Run IIa, which began in March 2001. One of the cornerstones of this
Run IIb upgrade is a completely redesigned level-1 calorimeter trigger system.
The new system employs novel architecture and algorithms to retain high
efficiency for interesting events while substantially increasing rejection of
background. We describe the design and implementation of the new level-1
calorimeter trigger hardware and discuss its performance during Run IIb data
taking. In addition to strengthening the physics capabilities of D0, this
trigger system will provide valuable insight into the operation of analogous
devices to be used at LHC experiments.Comment: 43 pages, 20 figures, version published in Nucl. Instrum. and Methods
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