Measuring supersymmetric particle masses at the LHC in scenarios with baryon-number R-parity violating couplings

The measurement of sparticle masses in the Minimal Supersymmetric Standard Model at the LHC is analysed, in the scenario where the lightest neutralino, the ⁰₁, decays into three quarks. Such decays, occurring through the baryon-number violating coupling λ''_ijk, pose a severe challenge to the capability of the LHC detectors since the final state has no missing energy signature and a high jet multiplicity. We focus on the case λ''₂₁₂≠0 which is the most difficult experimentally. The proposed method is valid over a wide range of SUGRA parameter space with λ''₂₁₂ ∼ 10⁻⁵−0.1. Simulations are performed of the ATLAS detector at the Large Hadron Collider. Using the ⁰₁ from the decay chain _L→⁰₂q→_Rℓq→⁰₁ℓℓq, we show that the ⁰₁ and ⁰₂ masses can be measured by 3-jet and 3-jet + lepton pair invariant mass combinations. At the SUGRA pointm₀ = 100 GeV, m_1/2 = 300 GeV,A₀ = 300 GeV, tan β = 10, μ > 0 and with λ^''₂₁₂ = 0.005, we achieve statistical (systematic) errors of 3 (3), 3 (3), 0.3 (4) and 5 (12) GeV, respectively for the masses of the ⁰₁, ⁰₂, _R and _L, with an integrated luminosity of 30 fb⁻¹.