Constraining Liberated Supergravity

TL;DR

This paper investigates the limitations of liberated supergravity theories, showing they cannot significantly alter the cosmological constant or particle masses, but can still support viable inflation models with a changing supersymmetry breaking scale.

Contribution

It demonstrates that liberated supergravity theories are effective only below a certain cutoff and proposes a simple inflation model with a variable supersymmetry breaking scale.

Findings

Cutoff scale restricts observable effects of new scalar potentials.

Proposed inflation model remains valid above the Hubble scale.

Changing supersymmetry breaking scale enables viable inflation after constraints.

Abstract

Fermionic terms in a class of locally supersymmetric theories called "liberated supergravity" are nonrenormalizable interactions proportional to inverse powers of the supersymmetry breaking scale and Planck mass. This property defines an intrinsic cutoff for liberated supergravities, which are therefore effective theories valid only below energies that never exceed the cutoff. Requiring that the cutoff exceeds current theoretical and observational bounds shows that the new scalar potential terms allowed by liberated supergravity can neither change the cosmological constant predicted by supergravity by any observable amount, nor give measurable contributions to particle masses. We show that it is nevertheless possible to define a simple liberated supergravity model of slow roll inflation valid up to energy scales that are well above the Hubble parameter during inflation and exceeds observable limits after inflation. The key to constructing a viable model is to change the supersymmetry breaking scale, from a Planck-scale value during inflation, to TeV-scale after inflation.