arXiv subjects

B. Bekman

Publications and source records attributed to B. Bekman.

3 recordsLinked to original sources

arXiv2005

Neutrino events from SN1987A revisited

The e- and e+ energy spectra from the SN1987A Supernova neutrino burst interactions are calculated and compared to the observed spectra in Kamiokande-II and IMB experiments. Neutrino oscillations in Supernova and regeneration effects in the Earth, for four combinations of neutrino mass hierarchy (Direct/Inverted) and the value of the mixing angle Theta_13 (Large/Small), are taken into account. The influence of the (anti)neutrino production spectra in Supernova on the observed, in Kamiokande-II and IMB detectors, e-/e+ spectra is shown.

hep-ph↗

arXiv2004

Detection of Supernova Neutrinos

Matter effects on neutrino oscillations in both, a supernova and the Earth, change the observed supernova neutrino spectra. We calculate the expected number of supernova neutrino interactions for ICARUS, SK and SNO detectors as a function of the distance which they traveled in the Earth. Calculations are performed for supernova type II at 10kpc from the Earth, using standard supernova neutrino fluxes described by thermal Fermi--Dirac distributions and the PREM I Earth matter density profile.

hep-ph↗

arXiv2002

Matter effects and CP violating neutrino oscillations with non-decoupling heavy neutrinos

The evolution equation for active and sterile neutrinos propagating in general anisotropic or polarized background environment is found and solved for a special case when heavy neutrinos do not decouple, resulting in non-unitary mixing among light neutrino states. Then new CP violating neutrino oscillation effects appear. In contrast to the standard unitary neutrino oscillations these effects can be visible even for two flavour neutrino transitions and even if one of the elements of the neutrino mixing matrix is equal to zero. They do not necessarily vanish with $δm^{2} \to 0$ and they are different for various pairs of flavour neutrino transitions ($ν_e \to ν_μ$), ($ν_μ\to ν_τ$), ($ν_τ\to ν_e$). Neutrino oscillations in vacuum and Earth's matter are calculated for some fixed baseline experiments and a comparison between unitary and non-unitary oscillations are presented. It is shown, taking into account the present experimental constraints, that heavy neutrino states can affect CP and T asymmetries. This is especially true in the case of $ν_μ\to ν_τ$ oscillations.

hep-ph↗