[Triumf-seminars] TRIUMF Theory Seminar today at 13:00

[TRIUMF Seminars]

Date/Time: Tue 2013-05-07 at 13:00

Location:  Theory Room         

Speaker:   Yuhsin Tsai (UC Davis)

Title:     Soft RPV through the baryon portal

Abstract: 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. Here we introduce a  scenario in which baryonic R-parity violation (RPV) arises effectively from soft
 SUSY breaking interactions, but leptonic RPV remains accidentally forbidden to evade constraints from proton decay and FCNCs. 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 level; RPV couplings between quarks and squarks arise only at loop level and receive additional suppression. 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 on cosmological timescales and can be a viable dark matter candidate.



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