2008/03/31 by Yasaman Farzan, Alexei Smirnov, Alexei Yu Smirnov
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Cosmology and Gravitation Theories #Neutrino Physics Research #hep-ph
paper · pdf · doi:10.1016/j.nuclphysb.2008.07.028
published as Nucl.Phys.B805:356-376,2008 · 31 pages; A discussion on "coherent broadening" is added
openalex publication_date 2008/08/06 · arxiv created 2008/09/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
For cosmic neutrinos we study the conditions and the effects of the coherence loss as well as coherent broadening of the spectrum. We evaluate the width of the neutrino wavepacket produced by charged particles under various circumstances: in an interaction-free environment, in a radiation-dominated medium (typical of the sources of the gamma ray bursts) and in the presence of a magnetic field. The effect of the magnetic field on the wavepacket size appears to be more important than the scattering. If the magnetic field at the source is larger than ∼10 Gauss, the coherence of neutrinos will be lost while traveling over cosmological distances. Various applications of these results have been considered. We find that for large magnetic fields (B> 109 Gauss) and high energies (Eν>\rm PeV), "coherent broadening" can modify the energy spectrum of neutrinos. In the coherent case, averaging out the oscillatory terms of the probabilities does not induce any statistical uncertainty beyond what expected in the absence of these terms. A deviation from the standard quantum mechanics that preserves average energy and unitarity cannot alter the picture.