Closing up a light stop window in natural SUSY at LHC

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• 作者：Archil Kobakhidze^b ; Ning Liu^a ; ^{wlln@mail.ustc.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Lei Wu^b ; ^{wuleihep@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Jin Min Yang^c ; ^d ; Mengchao Zhang^d ; ^{mczhang@itp.ac.cn" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Physics Letters B
• 出版年：2016
• 出版时间：10 April 2016
• 年：2016
• 卷：755
• 期：Complete
• 页码：76-81
• 全文大小：824 K

文摘

Top squark (stop) plays a key role in the radiative stability of the Higgs boson mass in supersymmetry (SUSY). In this work, we use the LHC Run-1 data to determine the lower mass limit of the right-handed stop in a natural SUSY scenario, where the higgsinos width="26" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si1.gif">${\tilde{\chi }}_{1,2}^0$ and width="20" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si2.gif">${\tilde{\chi }}_1^{\pm }$ are light and nearly degenerate. We find that the stop mass has been excluded up to 430 GeV for width="96" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si3.gif">$m_{{\tilde{\chi }}_1^0}\lesssim 250\text{GeV}$ and to 540 GeV for width="96" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si4.gif">$m_{{\tilde{\chi }}_1^0}\simeq 100\text{GeV}$ by the Run-1 SUSY searches for width="62" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si5.gif">$2b+E_T^{\mathit{miss}}$ and width="97" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si116.gif">$1\ell +\text{<italic>jets</italic>}+E_T^{\mathit{miss}}$, respectively. In a small strip of parameter space with width="96" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si103.gif">$m_{{\tilde{\chi }}_1^0}\gtrsim 190\text{GeV}$, the stop mass can still be as light as 210 GeV and compatible with the Higgs mass measurement and the monojet bound. The 14 TeV LHC with a luminosity of 20 fb⁻¹$20{\text{fb}}^{-1}$ can further cover such a light stop window by monojet and width="62" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316000897-si5.gif">$2b+E_T^{\mathit{miss}}$ searches and push the lower bound of the stop mass to 710 GeV. We also explore the potential to use the Higgs golden ratio, D_γγ=σ(pp→h→γγ)/σ(pp→h→ZZ^⁎→4ℓ^±)$D_{\gamma \gamma }=\sigma (pp\to h\to \gamma \gamma )/\sigma (pp\to h\to Z{Z}^{⁎}\to 4{\ell }^{\pm })$, as a complementary probe for the light and compressed stop. If this golden ratio can be measured at percent level at the high luminosity LHC (HL-LHC) or future e⁺e⁻$e^{+}{e}^{-}$ colliders, the light stop can be excluded for most of the currently allowed parameter region.