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Theoretical Physycs Group at Scuola Normale Superiore
Piazza dei Cavalieri, 7
56100 Pisa PI - Italy
ph. +39 050 509203
ph. +39 050 509111

Brando Bellazzini (IPhT, Saclay)

Quarks and Leptons as composite (pseudo-)Goldstini

Abstract
I present the idea that quarks and leptons of the Standard Models are composite particles which appear elementary at the electroweak scale because the strong dynamics gets imprinted in highly irrelevant operators. The more irrelevant the new interactions, the more this scenario resembles the Standard Model at low energy. The fastest decoupling of the effects due to compositeness which is compatible with unitarity and crossing symmetry corresponds to presence of dimension-8 four-fermion interactions. Such a maximally-fast energy scaling is obtained naturally by identifying quarks and leptons as pseudo-Goldstini of a spontaneously broken (and approximate) supersymmetry. I discuss the properties of the new interactions and their experimental signatures at the LHC.