PHYSICS DISSERTATION DEFENSE: Payel Mukhopadhyay

Ph.D. Candidate:  Payel Mukhopadhyay

Research Advisor:  Joanne Hewett

Co-Advisor: Alex Friedland

Date: 19th August

Time: 2 pm

Location: PAB 102

Zoom Link:  https://stanford.zoom.us/j/9245231845

Zoom Password: email nickswan [at] stanford.edu (nickswan[at]stanford[dot]edu) for password.

 

Title: On the physics of supernova outflows - from hydrodynamics to nucleosynthesis

Abstract: Core-collapse supernovae (CCSNe) have shaped our galaxy, played an essential role in the formation of the solar system, and created many elements found on Earth, including oxygen. Some of the outstanding questions in the field of core collapse supernovae are intimately tied to neutrinos. Neutrinos are produced in copious numbers in a CCSNe explosion and are messengers of the physical processes occurring in and around the hot and dense supernova core where matter reaches nuclear densities. In the supernova explosion detected in 1987, known as SN1987A, only 25 neutrino events were detected, yet this already provided vital clues to the explosion mechanism. With the next-generation neutrino detectors such as DUNE and Hyper-Kamiokande, which will have the capacity to detect many thousands of neutrino events from the next Galactic supernova explosion, qualitatively new understanding of the supernova phenomenon will be achieved. The question is then what features one may expect to see in these detectors and how can one reconstruct the explosion dynamics from the neutrino observations.

In this talk, I will focus on the physics that takes place several seconds after the explosion is launched. I will focus on a region known as the `hot bubble' of supernova explosion, which hosts a plethora of interesting phenomena, ranging from non-trivial neutrino oscillations to nucleosynthesis of heavy elements. I will show that the hydrodynamics of this hot bubble can crucially impact neutrino oscillations and that the imprints of the resulting density features on the neutrino spectrum can be detected in DUNE. I will also show that the hot bubble can be a site of a certain nucleosynthesis process, known as the nu p- process, which helps resolve a 30 year old puzzle regarding the origin of certain proton-rich isotopes observed in the Solar System, such a 92,94Molybdenum and 96,98Ruthenium.