Off-trail SUSY

Abstract

We present two distinct topics: I) We describe the propagation of a spin-3/2 state in a background which preserves invariance under space translations and rotations but not under Lorentz boost transformations. We start by building a generalisation of the Volkov-Akulov Lagrangian for a goldstino in a fluid. A superHiggs mechanism leads to the modified Rarita-Schwinger Lagrangian describing a slow gravitino. We identify the physical propagating degrees of freedom and derive the corresponding equations of motion. This includes some new results. II) Fake Split Supersymmetry Models are proposed to alleviate some of the problems of the original Split SUSY. In particular it is no more necessary to restrict to a Mini-Split scenario as higher values of the supersymmetry breaking scale (Mega-Split) are now allowed. The FSSM relies on swapping the higgsinos for new states in identical gauge group representations but different Yukawa couplings.

Salvage of too slow gravitinos

“…In the super-Higgs mechanism, a spin 1/2 fermion, the goldstino, combines with the gravitino and provides it with the appropriate number of degrees of freedom for a massive spin 3/2 [1][2][3][4][5]. When the spin 1/2 propagates in a generic background with a non-relativistic dispersion relation, for instance at the sound speed c s < 1 in fluids, the result of the super-Higgs mechanism has been denoted "slow gravitinos" [6][7][8][9][10]. Such situations might occur in cosmological backgrounds as cosmological solutions treat time and space differently [11][12][13][14][15].…”