Simultaneous B and L Violation: New Signatures from RPV-SUSY

Abstract

Studies of R-parity violating (RPV) supersymmetry typically assume that nucleon stability is protected by approximate baryon number (B) or lepton number (L) conservation. We present a new class of RPV models that violate B and L simultaneously (BLRPV), without inducing rapid nucleon decay. These models feature an approximate $Z_2^e\times Z_2^{\mu }\times Z_2^{\tau }$ flavor symmetry, which forbids 2-body nucleon decay and ensures that flavor antisymmetric $LL{E}^c$ couplings are the only non-negligible L-violating operators. Nucleons are predicted to decay through $N\to Ke\mu \nu$ and $n\to e\mu \nu$; the resulting bounds on RPV couplings are rather mild. Novel collider phenomenology arises because the superpartners can decay through both L-violating and B-violating couplings. This can lead to, for example, final states with high jet multiplicity and multiple leptons of different flavor, or a spectrum in which depending on the superpartner, either B or L violating decays dominate. BLRPV can also provide a natural setting for displaced $\tilde{\nu }\to \mu e$ decays, which evade many existing collider searches for RPV supersymmetry.

Comments: 27 pages (8 pages of appendices), 10 figures. v3: Made minor revisions suggested by referee, particularly Section 4A and Section 5. Conclusions unchanged