Non-Decoupling New Particles
by
1423 in building 1
KIAS
Title: Non-Decoupling New Particles
Speaker: Ian Banta (UCSB)
Abstract: We describe a new class of beyond the Standard Model states that we call "Loryons." They have the defining characteristic of being non-decoupling, in the sense that their physical mass is dominated by a contribution from the vacuum expectation value of the Higgs boson. The stakes are high: the discovery of a Loryon would tell us that electroweak symmetry must be non-linearly realized in the effective field theory of the Standard Model. We first provide a complete catalog of Loryon representations under mild assumptions. We then discuss bounds from perturbative unitarity, which place an upper limit on the mass of new Loryons and thus define a finite parameter space for exploration. We then turn to examining the constraints on the parameter space from Higgs couplings measurements, precision electroweak tests, and direct collider searches. We show that most fermionic candidates are already ruled out (with some notable exceptions), while much of the scalar Loryon parameter space is still wide open for discovery.
