Evolution of Helicity Property of Relic Neutrinos and Implications on Their Detection

by Jen-Chieh Peng (University of Illinois)

Thursday 16 Mar 2023, 15:00 → 16:00 US/Eastern

Neutrinos in the early Universe decoupled essentially in helicity eigenstates. As they propagate through the Universe, their helicities could be modified via two effects. First, neutrinos with a finite magnetic moment would rotate their spins with respect to their momenta as they encounter cosmic magnetic fields, modifying their helicities. Second, the bending of neutrino's spin by a gravitational field lags the bending of its momentum, again modifying its helicity. We calculate both effects and investigate the implications of the helicity modification on the detection of relic neutrinos using the Inverse Tritium Beta Decay (ITBD) reaction. We find that the ITBD rate depends sensitively on the neutrino mass hierarchy and on the Dirac or Majorana nature of the neutrinos. This talk is based on three recent papers in collaboration with Gordon Baym.

---

REMOTE ONLY SEMINAR

Zoom link: https://cern.zoom.us/j/63173612170?pwd=cGZKZWUzUDdhRFRJb3dvellBbnpmZz09

Meeting ID: 631 7361 2170
Passcode: 314159

BNL_2023_peng.pdf