Recently, a proposal [R. N. Mohapatra and S. Nandi, Phys. Rev. Lett. 79, 181 (1997)] was made for a new class of gauge-mediated supersymmetry-breaking (GMSB) models where the standard model gauge group is embedded into the gauge group $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_{I_{3R}}\times {U\left(1\right)\mathrm{}}_{B-L}$ [or $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_R\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_{B-L}]$ at the supersymmetry-breaking scale $\Lambda$. Supersymmetry breaking is transmitted to the visible sector via the same fields that are responsible for gauge symmetry breaking rather than by vector-like quarks and leptons as in the conventional GMSB models. These models have a number of attractive properties such as exact $R$-parity conservation, nonvanishing neutrino masses and a solution to the SUSY $\mathrm{CP}$ (and strong $CP)$ problem. In this paper, we present the detailed sparticle spectroscopy and phenomenological implications of the various models of this class that embody the general spirit of our previous work but use a larger variety of messenger fields. A distinct characteristic of this class of models is that unlike the conventional GMSB ones, the lightest neutralino is always the NLSP leading to photonic events in the colliders.

• Received 14 April 1997

DOI:https://doi.org/10.1103/PhysRevD.56.5466