WZ plus missing-E T signal from gaugino pair production at LHC7

Abstract

Abstract LHC searches for supersymmetry currently focus on strongly produced sparticles, which are copiously produced if gluinos and squarks have masses of a few hundred GeV. However, in supersymmetric models with heavy scalars, as favored by the decoupling solution to the SUSY flavor and CP problems, and $ {m_{{\widetilde{g}}}} \gtrsim {5}00{\text{ GeV}} $ as indicated by recent LHC results, chargino-neutralino $ \left( {\widetilde{W}_1^{\pm }{{\widetilde{Z}}_2}} \right) $ production is the dominant cross section for $ {m_{{{{\widetilde{W}}_1}}}} \sim {m_{{{{\widetilde{Z}}_2}}}} < {m_{{\widetilde{g}}}}/3 $ at LHC with $ \sqrt {s} = 7\;{\text{TeV}} $ (LHC7). Furthermore, if $ {m_{{{{\widetilde{Z}}_1}}}} + {m_Z} \lesssim {m_{{{{\widetilde{Z}}_2}}}} \lesssim {m_{{{{\widetilde{Z}}_1}}}} + {m_h} $ , then $ {\widetilde{Z}_2} $ dominantly decays via $ {\widetilde{Z}_2} \to {\widetilde{Z}_1}Z $ , while $ {\widetilde{W}_1} $ decays via $ {\widetilde{W}_1} \to {\widetilde{Z}_1}W $ . We investigate the LHC7 reach in the "Image missing" channel (for both leptonic and hadronic decays of the W boson) in models with and without the assumption of gaugino mass universality. In the case of the mSUGRA/CMSSM model with heavy squark masses, the LHC7 discovery reach in the "Image missing" channel becomes competetive with the reach in the canonical "Image missing" + jets channel for integrated luminosities ∼30 fb−1. We also present the LHC7 reach for a simplified model with arbitrary $ {m_{{{{\widetilde{Z}}_1}}}} $ and $ {m_{{{{\widetilde{W}}_1}}}} \sim {m_{{\widetilde{Z}2}}} $ . Here, we find a reach of up to $ {m_{{{{\widetilde{W}}_1}}}} $ ∼ 200 (250) GeV for 10 (30) fb−1.