Search for Bs0â†Î+Î- and Bd0â†Î +Î- Decays in pp Collisions with CDF II
Physical Review Letters 95:22 (2005)
Abstract:
We report on a search for Bs0â†Î+Î- and Bd0â†Î+Î- decays in ppÂcollisions at s=1.96TeV using 364â€â€pb-1 of data collected by the CDF II detector at the Fermilab Tevatron Collider. After applying all selection requirements, we observe no candidates inside the Bs0 or Bd0 mass windows. The resulting upper limits on the branching fractions are B(Bs0↠Î+Î-)<1.5Ã-10-7 and B(Bd0â†Î+Î-) <3.9Ã-10-8 at 90% confidence level. © 2005 The American Physical Society.The Growth, Polarization, and Motion of the Radio Afterglow from the Giant Flare from SGR 1806–20
The Astrophysical Journal American Astronomical Society 634:1 (2005) l93-l96
Structure in the radio counterpart to the 2004 Dec 27 giant flare from SGR 1806-20
(2005)
Determining the cosmic ray ionization rate in dynamically evolving clouds
ArXiv astro-ph/0511064 (2005)
Abstract:
The ionization fraction is an important factor in determining the chemical and physical evolution of star forming regions. In the dense, dark starless cores of such objects, the ionization rate is dominated by cosmic rays; it is therefore possible to use simple analytic estimators, based on the relative abundances of different molecular tracers, to determine the cosmic ray ionization rate. This paper uses a simple model to investigate the accuracy of two well-known estimators in dynamically evolving molecular clouds. It is found that, although the analytical formulae based on the abundances of H3+,H2,CO,O,H2O and HCO+ give a reasonably accurate measure of the cosmic ray ionization rate in static, quiescent clouds, significant discrepancies occur in rapidly evolving (collapsing) clouds. As recent evidence suggests that molecular clouds may consist of complex, dynamically evolving sub-structure, we conclude that simple abundance ratios do not provide reliable estimates of the cosmic ray ionization rate in dynamically active regions.Observation of the P11 state of charmonium
Physical Review D American Physical Society (APS) 72:9 (2005) 092004