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تسجيل مستخدم جديدRadiatively-driven natural supersymmetry at the LHC
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Radiatively-driven natural supersymmetry (RNS) potentially reconciles the Z and Higgs boson masses close to 100 GeV with gluinos and squarks lying beyond the TeV scale. Requiring no large cancellations at the electroweak scale in constructing M_Z=91.2 GeV while maintaining a light Higgs scalar with m_h 125 GeV implies a sparticle mass spectrum including light higgsinos with mass 100-300 GeV, electroweak gauginos in the 300-1200 GeV range, gluinos at 1-4 TeV and top/bottom squarks in the 1-4 TeV range (probably beyond LHC reach), while first/second generation matter scalars can exist in the 5-30 TeV range (far beyond LHC reach). We investigate several characteristic signals for RNS at LHC14. Gluino pair production yields a reach up to m_{tg} 1.7 TeV for 300 fb^{-1}. Wino pair production -- pptotw_2tz_4 and tw_2tw_2 -- leads to a unique same-sign diboson (SSdB) signature accompanied by modest jet activity from daughter higgsino decays; this signature provides the best reach up to m_{tg} 2.1 TeV within this framework. Wino pair production also leads to final states with (WZto 3ell)+eslt as well as 4ell+eslt which give confirmatory signals up to m_{tg} 1.4 TeV. Directly produced light higgsinos yield a clean, soft trilepton signature (due to very low visible energy release) which can be visible, but only for a not-too-small a tz_2-tz_1 mass gap. The clean SSdB signal -- as well as the distinctive mass shape of the dilepton mass distribution from tz_{2,3}totz_1ellell decays if this is accessible -- will mark the presence of light higgsinos which are necessary for natural SUSY. While an e^+e^- collider operating with sqrt{s} 600 GeV should unequivocally reveal the predicted light higgsinos, the RNS model with m_{1/2}> 1 TeV may elude all LHC14 search strategies even while maintaining a high degree of electroweak naturalness.
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Radiatively-driven natural SUSY (RNS) models enjoy electroweak naturalness at the $10%$ level while respecting LHC sparticle and Higgs mass constraints. Gluino and top squark masses can range up to several TeV (with other squarks even heavier) but a
set of light Higgsinos are required with mass not too far above $m_hsim 125$ GeV. Within the RNS framework, gluinos dominantly decay via ${tilde g} to t{tilde t}_1^{*}, bar{t}{tilde t}_1 to tbar{t}{widetilde Z}_{1,2}$ or $tbar{b}{widetilde W}_1^-+c.c.$, where the decay products of the higgsino-like ${widetilde W}_1$ and ${widetilde Z}_2$ are very soft. Gluino pair production is, therefore, signalled by events with up to four hard $b$-jets and large ${ ot!!{E_T}}$. We devise a set of cuts to isolate a relatively pure gluino sample at the (high luminosity) LHC and show that in the RNS model with very heavy squarks, the gluino signal will be accessible for $m_{{tilde g}} < 2400 (2800)$ GeV for an integrated luminosity of 300 (3000) fb$^{-1}$. We also show that the measurement of the rate of gluino events in the clean sample mentioned above allows for a determination of $m_{{tilde g}}$ with a statistical precision of $2.5-5%$ (depending on the integrated luminosity and the gluino mass) over the range of gluino masses where a $5sigma$ discovery is possible at the LHC.
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