Astrophysical searches for sterile neutrino and axion-like particle dark matter

Date

Thursday, March 21, 2024
16:00 - 17:00

Abstract

In this talk I will discuss two dark matter candidates, sterile neutrinos and axion-like particles (ALPs). In the first part of my talk I will describe a novel mechanism for producing a cosmologically-significant relic density of sterile neutrinos. This scheme invokes a dark population transfer involving two (or more) sterile neutrinos, producing a dark matter candidate that can evade current electromagnetic and structure-based bounds, but may nevertheless be probed by future observations. In the second part of my talk I will pivot to a discussion of astrophysical searches for ALPs. Recently a detection technique using the CMB was proposed which relies on the fact that the ALP oscillates at a frequency set by its mass, leading to a time-dependent birefringence that may be observed in the polarization of the CMB. Using two years of data from the POLARBEAR telescope, we searched for this effect and placed a median 95% upper limit of 0.65 degrees on the sinusoid amplitude for oscillation periods between 2 days and 50 days.

In this talk I will discuss two dark matter candidates, sterile neutrinos and axion-like particles (ALPs). In the first part of my talk I will describe a novel mechanism for producing a cosmologically-significant relic density of sterile neutrinos. This scheme invokes a dark population transfer involving two (or more) sterile neutrinos, producing a dark matter candidate that can evade current electromagnetic and structure-based bounds, but may nevertheless be probed by future observations. In the second part of my talk I will pivot to a discussion of astrophysical searches for ALPs. Recently a detection technique using the CMB was proposed which relies on the fact that the ALP oscillates at a frequency set by its mass, leading to a time-dependent birefringence that may be observed in the polarization of the CMB. Using two years of data from the POLARBEAR telescope, we searched for this effect and placed a median 95% upper limit of 0.65 degrees on the sinusoid amplitude for oscillation periods between 2 days and 50 days.

Indico: https://indico.nikhef.nl/event/5385/

Zoom Link: https://nikhef.zoom.us/j/92535772755?pwd=aFZySWFtS1NXaEhZSmhKRzdtYXFIUT09
Meeting ID: 925 3577 2755
Passcode: nikh4f

Organiser

Nikhef

Room number

Veltman center

Category

Group Seminar

Topics

astrophysics, gravitational and astroparticle physics

Speakers

Jacob Spisak (University of California San Diego)