"Neutrino-antineutrino pair production from potential gradient"

Presented by Dr. Yikun Wang, Postdoctoral Fellow, Johns Hopkins University

In this talk, I will discuss a particle-antiparticle pair production mechanism under the category of Schwinger effect. In the presence of a strong, supercritical, potential, particles and antiparticles can be pair produced from the vacuum. This has been widely studied for gauge fields, both in QED and QCD, and gravitation fields, relevant for black hole physics. We argue that the pair production could be sourced by alternative potentials, provided vector or chiral vector couplings to fermions. 

As an example, we show that neutrino-antineutrino can be pair produced under a strong matter potential. The supercritical condition requires that the matter potential to be greater than the neutrino mass, which can be realized in dense objects such as neutron stars. Additionally, a sizable pair production rate requires the potential to have a large gradient, such as a steep slope, or a narrow width for a step-like potential. The latter can be achieved in neutron stars provided discontinuity in its density profile, that can present as a result of phase transitions in neutron star. Provided with necessary conditions, the neutrino-antineutrino could be produced at a sizable rate comparable to other emission mechanisms. With the core temperature greater than the neutrino kinetic energy, this opens up a new channel for neutron star cooling. After escaping the neutron star, these neutrinos and antineutrinos, with energy much greater than cosmic neutrino backgrounds, can potentially be detected in direct detection experiments.