The $\mu$ problem, and B and L Conservation with a Discrete Gauge R   Symmetry
  We examine in a generic context how the $\mu$ problem can be resolved by means of a spontaneously broken gauge symmetry. We then focus on the new scheme based on a discrete gauge R symmetry which is spontaneously broken by nonperturbative hidden sector dynamics triggering supersymmetry breaking also. The possibility to suppress the dangerous baryon and/or lepton number violating interactions by means of this discrete R symmetry is examined also together with some phenomenological consequences. 
Kiwoon Choi, Eung Jin Chun, and Hyungdo Kim