Search for direct pair production of scalar top quarks in the single- and dilepton channels in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV

Abstract

Results are reported from a search for the top squark t 1 , the lighter of the two supersymmetric partners of the top quark. The data sample corresponds to 19.7 fb −1 of proton-proton collisions at √ s = 8 TeV collected with the CMS detector at the LHC.The search targets t 1 → b χ ± 1 and t 1 → t ( * ) χ 0 1 decay modes, where χ ± 1 and χ 0 1 are the lightest chargino and neutralino, respectively. The reconstructed final state consists of jets, b jets, missing transverse energy, and either one or two leptons. Leading backgrounds are determined from data. No significant excess in data is observed above the expectation from standard model processes. The results exclude a region of the two-dimensional plane of possible t 1 and χ 0 1 masses. The highest excluded t 1 and χ 0 1 masses are about 700 GeV and 250 GeV, respectively.

Second stop and sbottom searches with a stealth stop

“…For even smaller mass difference, there are some constraints from several search modest 1 → W bχ 0 1 , cχ 0 1 , or bf f χ 0 1 depending on the mass difference [51][52][53][54]. The bounds on mt 1 in these cases are around 300 GeV from the Run 1 data [23,[55][56][57][58][59][60][61]. The most recent Run 2 analyses exclude a stop mass up to 365 GeV for mt 1 − mχ0 1 = 90 GeV on the 3-body decay modẽ t 1 → W bχ 0 1 [62], and ∼ 450(360) GeV for the 4-body decays bf f χ 0 1 in the fully hadronic final state (opposite-sign leptons) search [13,63].…”

LHC benchmarks from flavored gauge mediation

“…Searches for stop pair-production are particularly relevant for Fig. 3 because of the small stop mass [52,53]. If the bino decays to a Z and a gravitino, and both the W from the top decay and the Z decay hadronically, the multi-jet plus missing energy searches are also useful [54,55].…”

From the 750 GeV diphoton resonance to multilepton excesses

“…however, are sensitive to a variety of kinematic variables including the mass of the particle carrying away the extra MET. In particular, constraints on direct stop productions in the tt+MET final states disappear when the LSP mass becomes larger than ∼ 300 GeV [142][143][144][145]. Due to these considerations, we choose the following benchmark in our study Model S: m X = 950 GeV ,…”