Abstract
Natural realisations of supersymmetry require light stops \( {\tilde{t}}_1 \), making them a prime target of LHC searches for physics beyond the Standard Model. Depending on the kinematic region, the main search channels are \( {\tilde{t}}_1\to t{\tilde{\chi}}_1^0 \), \( {\tilde{t}}_1\to W\ b{\tilde{\chi}}_1^0 \) and \( {\tilde{t}}_1\to c{\tilde{\chi}}_1^0 \). We first examine the interplay of these decay modes with \( {\tilde{c}}_1\to c{\tilde{\chi}}_1^0 \) in a model-independent fashion, revealing that a large parameter space region with stop mass values \( {m_{\tilde{\mathrm{t}}}}_{{}_1} \) up to 530 GeV is excluded for any \( {\tilde{t}}_1\to c{\tilde{\chi}}_1^0 \) branching ratio by LHC Run I data. The impact of \( {\tilde{c}}_1\to c{\tilde{\chi}}_1^0 \) decays is further illustrated for scenarios with stop-scharm mixing in the right-handed sector, where it has previously been observed that the stop mass limits can be significantly weakened for large mixing. Our analysis shows that once the \( {\tilde{c}}_1\to c{\tilde{\chi}}_1^0 \) bounds are taken into account, non-zero stop-scharm mixing can lead to an increase in the allowed parameter space by at most 35%, with large areas excluded for arbitrary mixing.
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Crivellin, A., Haisch, U. & Tunstall, L.C. Stop searches in flavourful supersymmetry. J. High Energ. Phys. 2016, 80 (2016). https://doi.org/10.1007/JHEP09(2016)080
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DOI: https://doi.org/10.1007/JHEP09(2016)080