R-parity violating decays of Wino chargino and wino neutralino LSPs and NLSPs at the LHC

Abstract

The R-parity violating decays of both Wino chargino and Wino neutralino LSPs are analyzed within the context of the B − L MSSM "heterotic standard model". These LSPs correspond to statistically determined initial soft supersymmetry breaking parameters which, when evolved using the renormalization group equations, lead to an effective theory satisfying all phenomenological requirements; including the observed electroweak vector boson and Higgs masses. The explicit decay channels of these LSPs into standard model particles, the analytic and numerical decay rates and the associated branching ratios are presented. The decay lengths of these RPV interactions are discussed. It is shown that the vast majority of these decays are "prompt", although a small, but calculable, number correspond to "displaced vertices" of various lengths. It is demonstrated that for a Wino chargino LSP, the NLSP is the Wino neutralino with a mass only slightly higher than the LSP-and vice-versa. As a consequence, we show that both the Wino chargino and Wino neutralino LSP/NLSP R-parity violating decays should be simultaneously observable at the CERN LHC.

R-parity violating decays of Bino neutralino LSPs at the LHC

“…Therefore, to summarize: the analysis of LSP Bino RPV decays carried out in this paper breaks naturally into two parts-1) the RPV decays of a Bino with mass M W ± < M B via "on-shell" W ± , Z 0 or h 0 bosons. Such decays are similar in form to those of both Wino chargino and Wino neutralino decays studied in [31] and 2) the RPV decays of a Bino with mass M B < M W ± via "off-shell" W ± , Z 0 or h 0 bosons. These decays are more complicated and the decay rates and branching ratios are considerably suppressed relative to the on-shell case.…”

“…This work presented the detailed theoretical underpinnings for any chargino and neutralino decay, but did not analyze any specific choices. The first such specific computation was carried out in [31] where, using the general formulas developed in [30], the decay modes, decay rates and branching ratios for Wino charginos and Wino neutralinos were computed and their experimental predictions presented. As was done in the case of the light stop LSP, the relationship of these RPV decays to the neutrino mass hierarchy was analyzed.…”

“…The Wino chargino and Wino neutralino LSPs in [31] were chosen because their decay products are readily observable by ATLAS at the LHC. However, it was noticed that one particular LSP, the neutral fermionic superpartnerB of the hypercharge gauge field Y -referred to as the "Bino"-was a much more prevalent LSP associated with viable B − L MSSM models.…”

“…1. All calculations in this paper, as well as those in previous analyses of the B − L MSSM such as [31], are carried out using the one-loop corrected β and γ renormalization group functions associated with the dimensionless and dimensionful parameters of the theory. However, we systematically ignore all higher-loop corrections to the RGEs as well as any finite one-loop and higher-loop corrections to the effective Lagrangian.…”

“…2. In this paper, as well as our previous papers [7,8,30,31], the initial soft supersymmetry breaking parameters are selected statistically using a "log-uniform" distribution over a mass range compatible with LHC energies. As discussed Section 2 of this paper, this is the standard distribution used in analyzing such initial conditions.…”