We will have a special edition of AstroParticle Lunch. Given the ongoing CCAPPSymposium, we will meet at 11:15 am and attend the talk by Cyril Creque-Sarbinowski, who is visiting in-person from Flatiron institute. The title and abstract of his talk are below
Chern-Simons Gravity and Neutrino Self-Interactions Dynamical Chern-Simons gravity (dCS)is a four-dimensional parity-violating extension of general relativity. Current models predict the effect of this extension to be negligible due to large decay constants f close to the scale of grand unified theories. Here, we present a construction of dCS allowing for much smaller decay constants, ranging from sub-eV to Planck scales. Specifically, we show that if there exists a fermion species with strong self-interactions, the short-wavelength fermion modes form a bound state. This bound state can then undergo dynamical symmetry breaking and the resulting pseudoscalar develops Yukawa interactions with the remaining long-wavelength fermion modes. Due to this new interaction, loop corrections with gravitons then realize a linear coupling between the pseudoscalar and the gravitational Chern-Simons term. The strength of this coupling is set by the Yukawa coupling constant divided by the fermion mass. Therefore, since self-interacting fermions with small masses are ideal, we identify neutrinos as promising candidates. For example, if a neutrino has a mass mν≲meV and the Yukawacoupling is order unity, the dCS decay constant can be as small as f∼10^3mν≲eV. We discuss other potential choices for fermions.
See you all at 11:15 am in Price Place or over Zoom,
https://osu.zoom.us/j/98700572484?pwd=b3AyTlR2d1dvUlZMb0xaUExnYVRPQT09