Abstract

In the collapsar scenario of the long duration Gamma-Ray Bursts(GRBs), multi-TeV neutrino emission is predicted as the jet makes its waythrough the stellar envelope. Such a neutrino signalis also expected for more general “failed” GRBs in which aputative jet is “choked” by a heavy envelope.If the neutrino oscillation parameters are in the atmospheric neutrinooscillation range, we show that the resonant oscillation ofelectron neutrino to muon/ natu neutrino can take place within the innerhigh density region of the choked jet progenitor with a heavy envelope,altering the neutrino flavor ratio on itssurface to $Phi^s_{u_e}:Phi^s_{u_mu}:Phi^s_{u_ au}=5:11:2$.Considering vacuum oscillation of these neutrinos on their way toEarth, the final flavor ratio detected on Earth is further modifiedto either :1.095:1.095$ for thelarge mixing angle solution to the solar neutrino data, or 1:1.3:1.3 formaximal mixing among the muon and tau neutrinos in vacuum.

Abstract

Abstract

Attempts to make observations at Planck scales are likely to cause formation of black holes .They will limit the possibility of observation at these scales.Such limitations can be accounted for by making the coordinates of spacetime not commute, just as in quantum theory, the Heisenberg uncertainty principle is taken care of by noncommuting position and momentum. These ideas go back to the 1930’s and Heisenberg and Schrodinger. This interesting history is traced. We then explain the formulation of such quantum spacetimes and their physical consequences. They modify the Pauli principle and lead to Pauli-forbidden transitions.They also lead to violations of causality at Planck scales with observable consequences for cosmic microwave background, Lorentz invariance, equality of particle-antiparticle lifetimes, CPT theorem etc. All these are reviewed in an elementary manner.

Abstract

Abstract