Theory Seminar (High Energy/Cosmology) |
Events on Friday, April 25th, 2014
- Soft R-Parity Violation
- Time: 2:15 pm
- Place: 5280 Chamberlin Hall
- Speaker: Yuhsin Tsai, Univ. of California-Davis
- Abstract: Supersymmetric (SUSY) models with R-parity generically predict sparticle decays with invisible neutralinos, which yield distinctive missing energy events at colliders. Since most LHC searches are designed with this expectation, the putative bounds on sparticle masses become considerably weaker if R-parity is violated so that squarks and gluinos decay to jets with large QCD backgrounds. In this talk I will introduce a scenario in which baryonic R-parity violation (RPV) arises effectively from soft SUSY-breaking interactions. The model features a global R-symmetry that initially forbids RPV interactions, a hidden R-breaking sector, and a heavy mediator that communicates this breaking to the visible sector. After R-symmetry breaking, the mediator is integrated out and an effective RPV A-term arises at tree leve. Although this mediator must be heavy compared to soft masses, the model introduces no new hierarchy since viable RPV can arise when the mediator mass is near the SUSY breaking scale. In generic regions of parameter space, a light thermally-produced gravitino is stable and can be a viable dark matter candidate.