Narrow Results

We investigate how the anticipated neutral current rate from SNO will sharpen our understanding of the solar neutrino anomaly. Quantitative analyses are performed with representative values of this rate in the expected range of 0.8–1.2. This would provide a 5–10σ signal for ν_e transition into a state containing an active neutrino component. Assuming this state to be purely active one can estimate both the ⁸B neutrino flux and the ν_e survival probability to a much higher precision than currently possible. Finally the measured value of the NC rate will have profound implications for the mass and mixing parameters of the solar neutrino oscillation solution.

f(R) gravity provides viable cosmology alternative to the ΛCDM model. We discuss the effect of massive neutrinos on matter power spectrum in this theory, to show that the anomalous growth of density fluctuations on small scales due to the scalaron force can be compensated by free streaming of neutrinos. As a result, models which predict observable deviation of the equation-of-state parameter w_DE from w_DE = -1 may be reconciled with observations of matter clustering if the total neutrino mass is O(0.5 eV).

It is one of the biggest challenge in particle physics and cosmology to determine the mass of neutrinos. Current neutrinoless double beta decay experiment show that the total neutrino mass is smaller than 1–6 eV.

In recent years, precise CMB data make it possible to constrain neutrino masses cosmologically. It says that the total neutrino mass is smaller than 2 eV in standard ACDM model.¹ But if there are other physical processes which affects the CMB anisotropies, such constraint may be changed. A primordial magnetic field (PMF) is one of such physical processes. In this work, we constrain the total neutrino mass from CMB anisotropies with the PMF effect.