Phenomenological Motivation for Gravitational Positivity Bounds: A Case Study of Dark Sector Physics

Abstract

Positivity bounds on scattering amplitudes provide a necessary condition for a low-energy effective field theory to have a consistent ultraviolet completion. Their extension to gravity theories has been studied in the past years aiming at application to the swampland program, showing that positivity bounds hold at least approximately even in the presence of gravity. An issue in this context is how much negativity is allowed for a given scattering process. In this paper we address importance of this rather technical issue by demonstrating that it is relevant to physics within the scope of ongoing experiments, especially in the context of dark sector physics. In particular, we provide detailed analysis of dark photon scenarios as an illustrative example. This motivates further studies on gravitational positivity bounds.

Swampland bounds on dark sectors

“…It is interesting that while both quantum gravity and the dark sector of our cosmos are open questions in Physics, we can make progress by combining our limited understanding of both these areas. Though the Swampland is a very active topic on the formal side, there has been so far little exploration of the phenomenological implications of existing Swampland bounds, as evident by the scarcity of Swampland literature on such an important topic as dark matter phenomenology (see, however, [28,[113][114][115][116], and especially [117], which bounds the parameter space of dark photons from positivity arguments). Our hope is that this paper will entice more phenomenology and astrophysics experts to uncover the consequences of Quantum Gravity for our universe.…”

Higher derivative corrections to black brane thermodynamics and the weak gravity conjecture

“…This perspective was illustrated in heteoric string examples [1] and then further studied, e.g., using modular invariance [30][31][32][33][34][35]. There are also some attempts to constrain the spectrum of light particles well below the Planck scale from consistency of gravitational scattering amplitudes [36][37][38][39][40][41][42]. The overall picture that there exist a tower of WGC states at various scales is summarized by the subLattic/Tower WGC [30,31,37,43].…”