Baryonic violation ofRparity from anomalousU(1)H

Abstract

Supersymmetric scenarios with R-parity conservation are becoming very constrained due to the lack of missing energy signals associated to heavy neutral particles, thus motivating scenarios with R-parity violation. In view of this, we consider a supersymmetric model with R-parity violation and extended by an anomalous horizontal U (1)H symmetry. A self-consistent framework with baryon-number violation is achieved along with a proper supression for lepton number violating dimension-5 operators, so that the proton can be sufficiently stable. With the introduction of righthanded neutrinos both Dirac and Majorana masses can be accommodated within this model. The implications for collider physics are discussed. I. INTRODUCTIONIn contrast to the standard model (SM), its supersymmetric version (SSM) does not have accidental lepton (L) and baryon-number (B) symmetries, and this can lead to major phenomenological problems, like fast proton decay. The standard solution to forbid all dangerous operators is the imposition of a discrete symmetry, like R-parity, and only in this minimal version (MSSM) the lightest supersymmetric particle (LSP), generally the neutralino, is stable, providing a good dark matter candidate. However, the recent results on searches for supersymmetry by CMS [1] and ATLAS [2] experiments have raised the bound on scalar and gluino masses, when they are approximately equal, to the order of 1.4 TeV for scenarios such as the R-parity conserving constrained minimal supersymmetric standard model (CMSSM). These searches are mainly based on missing transverse momentum carried by the LSP. A high mass scale for scalars and gluinos represents a potential chink in the initial proposal of the SSM as a possible solution to the hierarchy problem.However, these mass limits can be avoided in alternative supersymmetric models such as the R-parity violating SSM [3][4][5][6][7][8], where the LSP is usually assumed to be the gravitino which also provides a good decaying dark matter candidate [9,10]. The next to the lightest supersymmetric particle (NLSP) decays to standard model particles, and thus the missing transverse momentum may be considerably reduced [11][12][13][14][15][16][17][18]. In addition, if the involved couplings are small enough, the presence of displaced vertices may reduce the efficiency of the standard searches at LHC [11,18]. In particular, R-parity breaking scenarios with operators that violate B lead to the most difficult signals to be searched at hadron colliders [12][13][14][15][16][17]19]. The ad hoc choice of a discrete symmetry, like Lepton parity, to forbid all the L violating operators give rise to several issues. First, the size of the R-parity breaking couplings must be chosen precisely by hand in order to avoid constraints from flavor physics observables and other precision physics observables [8]. Second, dimension-5 L violating operators are automatically forbidden, and lepton-number violating neutrino mass terms cannot be generated at the renormalizable and nonrenormalizable level [20,2...

Soft RPV through the baryon portal

“…Similarly, "Collective RPV" [8] only allows RPV in particular combinations of couplings, so their overall effect yields the requisite suppression. Other models with similar features are found in [9][10][11][12][13][14].…”

Weak scale baryogenesis in a supersymmetric scenario with R-parity violation

“…in Partial Compositness (see [10] for a discussion on RPV in PC) and Minimal Flavor Violating SUSY (see [11,12] for the formulation of the MFV SUSY ansatz, and [13,14] for models in which MFV is implemented in the RPV sector), where one can also reasonably assume the B-violating couplings to be much larger than the L-violating ones. The possibility to avoid proton decay and other phenomenological constraints even in models with RPV, makes the latter interesting for model building (see [15][16][17][18][19][20][21] for more models of RPV).…”

Supersymmetric crevices: Missing signatures ofR-parity violation at the LHC

“…In fact until relatively recently there were no experimental searches that could robustly constrain colored superpartners as light as a few hundred GeV. The tight LHC constraints on Rparity conserving SUSY have therefore motivated significant theoretical work on baryonic R-parity violation, in particular attempting to address issues regarding its flavor structure and embedding in a UV model [6][7][8][9][10][11][12][13][14][15][16] as well as the origin of the primordial baryon asymmetry in the face of rapid washout of baryon number [17][18][19][20]. Lepton number violating RPV has in comparison seen little interest; it is often assumed that it cannot lower the bounds on superpartners as it introduces additional charged leptons and/or neutrinos.…”