ﻻ يوجد ملخص باللغة العربية
We argue that in at least a portion of the history of the universe the relic background neutrinos are spatially-extended, coherent superpositions of mass states. We show that an appropriate quantum mechanical treatment affects the neutrino mass values derived from cosmological data. The coherence scale of these neutrino flavor wavepackets can be an appreciable fraction of the causal horizon size, raising the possibility of spacetime curvature-induced decoherence.
We use the formalism of finite-temperature field theory to study the interactions of ultra-high energy (UHE) cosmic neutrinos with the thermal background of relic neutrinos. From the imaginary part of the neutrino self-energy, calculated in terms of
For the first time the antineutrino spectrum formed as a result of neutron and tritium decays during the epoch of primordial nucleosynthesis is calculated. This spectrum is a non-thermal increase in addition to the standard cosmic neutrino background
The standard model of cosmology predicts the existence of cosmic neutrino background in the present Universe. To detect cosmic relic neutrinos in the vicinity of the Earth, it is necessary to evaluate the gravitational clustering effects on relic neu
We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range, with coupli
We derive constraints on the relic abundance of a generic particle of mass $sim~1-10^{14}$ TeV which decays into neutrinos at cosmological epochs, using data from the Frejus and IMB nucleon decay detectors and the Flys Eye air shower array. The lifet