近期活动

INPAC Seminars

Supernova Neutrino Oscillation and the Origin of Heavy Elements

Professor Taka Kajino (National Astronomical Observatory of Japan, The University of Tokyo)
Wed, 2016-03-02 12:30 - 13:45
INPAC Meeting room(上海交通大学粒子物理宇宙学研究所,包玉刚图书馆东楼四楼(从北门进))

Energetic supernova (SN) neutrinos are subject to flavor oscillation due to the MSW effect which depends on still unknown neutrino "mass hierarchy". We first discuss how to constrain the "mass hierarchy" by measuring energy spectra of relic SN neutrinos in the SK & HK water-Cerenkov detector.  We will show that our theoretical model of BH formation in the SN explosion indicates a clear signal of the stiffness of EoS of proto-neutron stars and can solve the missing cosmic SN-rate problem and the red-supergiant problem simultaneously.  

 

Secondly, we discuss SN neutrino nucleosynthesis in order to determine the "mass hierarchy" more precisely.  Element genesis of several light-to-intermediate mass nuclei in SN explosions are known to be strongly affected by the MSW effect, which depends on where they are
synthesized.  We will propose new nucleosynthetic method to determine the "mass hierarchy" and show successful example of the cosmic clock.  

 

We,thirdly, discuss a recent debate of unidentified origin of the r-process (in SNe or binary neutron star mergers NSMs) which is expected to produce heavy elements like U and Th.  The r-process elements are affected by a new type of flavor oscillation called "neutrino collective oscillation" of many-body quantum effects.  Spectroscopic observations of early generations of halo stars (EMP stars) in the Milky Way show "universality" that the elemental abundance pattern in the EMP stars is quite similar to the solar-system abundance pattern.  Although MHD-jet SN model can naturally explain the "universality", their explosion mechanism is till poorly known
theoretically.  Binary NSMs could not have arrived at the early epoch of galactic evolution because of their cosmologically long coalescence time scale for too slow GW radiation.  We try to solve this twisted problem by carrying out large scale numerical simulations of the galactic chemo-dynamical evolution including SN feedback.  We will then propose a best model to solve the mystery of the origin of r-process elements.