منابع مشابه
Thermal Abundances of Heavy Particles
Matsumoto and Yoshimura [hep-ph/9910393] have argued that there are loop corrections to the number density of heavy particles (in thermal equilibrium with a gas of light particles) that are not Boltzmann suppressed by a factor of e at temperatures T well below the mass M of the heavy particle. We argue that this conclusion follows from an inappropriate definition of the number density of the he...
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In supersymmetric models with a long-lived stau being the lightest Standard Model superpartner, the stau abundance during primordial nucleosynthesis is tightly constrained. Considering the complete set of stau annihilation channels in the minimal supersymmetric Standard Model (MSSM) with real parameters for scenarios in which sparticle coannihilations are negligible, we calculate the decoupling...
متن کاملHeavy Element Abundances in Blue Compact Galaxies
We present high-quality ground-based spectroscopic observations of 54 supergiant H II regions in 50 low-metallicity blue compact galaxies with oxygen abundances 12 + log O/H between 7.1 and 8.3. We use the data to determine abundances for the elements N, O, Ne, S, Ar and Fe. We also analyze Hubble Space Telescope (HST) Faint Object Spectrograph archival spectra of 10 supergiant H II regions to ...
متن کاملHalo Star Abundances and Heavy Element Nucleosynthesis
Abundance observations of neutron-capture elements in halo stars are providing a wealth of new information on the nature of heavy element nucleosynthesis in evolved stars. In particular these observations provide clues and constraints to the synthesis mechanisms for the n-capture elements, suggestions for the site (or sites) for the r-process and Galactic chemical evolution. We have been obtain...
متن کاملRadiography with Heavy Particles*
The failure of x-ray diagnostic techniques to accurately detect tumors and other regions of abnormal density in soft tissue has been, for many years, a significant shortcoming of this important technique in medicine. Accelerated heavy particles with plastics for track detection can be used to record small differences in density in soft tissues which may correspond to biological structures and a...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 2000
ISSN: 0556-2821,1089-4918
DOI: 10.1103/physrevd.62.023505