## Events at Physics |

**Theory Seminar (High Energy/Cosmology)**

**Gravity safe, electroweak natural axionic solution to strong CP and SUSY mu problems**

**Date:**

**Thursday, February 21st**

**Time:**2:30 pm

**Place:**5280 Chamberlin Hall

**Speaker:**Howard Baer, University of Oklahoma

**Abstract:**Particle physics models with Peccei-Quinn (PQ) symmetry breaking as a consequence of supersymmetry (SUSY) breaking are attractive in that they solve the strong CP problem with a SUSY DFSZ-like axion, link the SUSY breaking and PQ breaking intermediate mass scales and can resolve the SUSY mu problem with a naturalness-required weak scale mu term whilst soft SUSY breaking terms inhabit the multi-TeV regime as required by LHC sparticle mass limits and the Higgs mass measurement.

On the negative ledger, models based on global symmetries suffer a generic gravity spoliation problem. We present two models based on the discrete R-symmetry Z_{24}^R-- which may emerge from compactification of 10-d Lorentzian spacetime in string theory-- where the mu term and dangerous proton decay and R-parity violating operators are either suppressed or forbidden while a gravity-safe PQ symmetry emerges as an accidental approximate global symmetry leading to a solution to the strong CP problem and a weak-scale/natural value for the mu term.

**Host:**Vernon Barger