# High Energy Physics Seminar

*,*Perimeter Institute and McMaster University

*,*

Note: Special time.

This talk explores some low-energy surprises that can emerge as consequences of accidental approximate scale invariances and a relatively supersymmetric gravity sector, both of which are arguably robust consequences of UV physics. Taken together these prove to be more than the sum of their parts. They suggest a non-supersymmetric particle physics sector coupled to a supersymmetric (and dark) gravity sector, and lead in particular to a framework wherein all particle masses are proportional to the

vev of a dilaton field: v = < phi >, with v ~ Mp/M ~ M/m where Mp, M and m respectively are the Planck, electroweak and neutrino mass scales. The potential for phi can be computed and can give hierarchically large values for v using only parameters of order ln v ~ 70. The potential at its minimum can be of order m^4, and if so the dilaton (which must couple to matter like a Brans-Dicke field with gravitational strength) must be light enough to mediate long-range forces. It nonetheless can evade constraints from solar-system

tests of gravity because the framework also turns out to contain (for free) a surprising new mechanism for screening long-range forces. This mechanism relies on the interactions between the dilaton and its axionic partner, which must also be very light and must couple (potentially observably) to QCD.

The talk is via Zoom.

Contact [email protected] for Zoom link