Free Meson Seminars
Neutrino Mass and Dark Matter in light of recent AMS-02 results in light of recent AMS-02 results
by Prof. Dilip Ghosh (Indian Association for the Cultivation of Science, Kolkata)
Thursday, September 18, 2014
from
to
(Asia/Kolkata)
at AG69
at AG69
Description |
We study a simple extension of the Standard Model supplemented by an electroweak triplet scalar field to accommodate small neutrino masses by the type-II seesaw mechanism, while an additional singlet scalar field can play the role of cold dark matter (DM) in our Universe. Using the recently released high precision data on positron fraction and flux from the AMS-02 experiment, we examine the DM interpretation of the observed positron excess in our model for two kinematically distinct scenarios with the DM and triplet scalar masses (a) non-degenerate (mDM ≫ mΔ) and (b) quasi-degenerate (mDM ≃ mΔ). We find that a good fit to the AMS-02 data can be obtained in both cases (a) and (b) with a normal hierarchy of neutrino masses, while the inverted hierarchy case is somewhat disfavored. Moreover, the absence of an excess anti-proton flux as suggested by PAMELA data sets an indirect upper limit on the DM-nucleon spin-independent elastic scattering cross section which is stronger than the existing DM direct detection bound from LUX in the AMS-02 preferred DM mass range. |