Search for bottom-squark pair production in $pp$ collision events at $\sqrt{s} = 13$ TeV with hadronically decaying $\tau$-leptons, $b$-jets and missing transverse momentum using the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Brad ; et al.
Phys.Rev.D 104 (2021) 032014, 2021.
Inspire Record 1851675 DOI 10.17182/hepdata.99788

A search for pair production of bottom squarks in events with hadronically decaying $\tau$-leptons, $b$-tagged jets and large missing transverse momentum is presented. The analyzed dataset is based on proton-proton collisions at $\sqrt{s}$ = 13 TeV delivered by the Large Hadron Collider and recorded by the ATLAS detector from 2015 to 2018, and corresponds to an integrated luminosity of 139 fb$^{-1}$. The observed data are compatible with the expected Standard Model background. Results are interpreted in a simplified model where each bottom squark is assumed to decay into the second-lightest neutralino $\tilde \chi_2^0$ and a bottom quark, with $\tilde \chi_2^0$ decaying into a Higgs boson and the lightest neutralino $\tilde \chi_1^0$. The search focuses on final states where at least one Higgs boson decays into a pair of hadronically decaying $\tau$-leptons. This allows the acceptance and thus the sensitivity to be significantly improved relative to the previous results at low masses of the $\tilde \chi_2^0$, where bottom-squark masses up to 850 GeV are excluded at the 95% confidence level, assuming a mass difference of 130 GeV between $\tilde \chi_2^0$ and $\tilde \chi_1^0$. Model-independent upper limits are also set on the cross section of processes beyond the Standard Model.

15 data tables

The expected exclusion contour at $95\%$ CL as a function of the M(Sbottom) vs. M(N2) with the $\Delta M$(N2,N1) = 130 GeV. Masses within the contour are excluded.

The observed exclusion contour at $95\%$ CL as a function of the M(Sbottom) vs. M(N2) with the $\Delta M$(N2,N1) = 130 GeV. Masses within the contour are excluded.

Acceptance in the Single-bin SR as a function of the M(Sbottom) vs. M(N2) with the $\Delta M$(N2,N1) = 130 GeV. Keep in mind that the acceptance is given in units of $10^{-4}$.

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Version 3
Search for bottom-squark pair production with the ATLAS detector in final states containing Higgs bosons, $b$-jets and missing transverse momentum

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
JHEP 12 (2019) 060, 2019.
Inspire Record 1748602 DOI 10.17182/hepdata.89408

The result of a search for the pair production of the lightest supersymmetric partner of the bottom quark ($\tilde{b}_{1}$) using 139 fb$^{-1}$ of proton-proton data collected at $\sqrt{s} = 13$ TeV by the ATLAS detector is reported. In the supersymmetric scenarios considered both of the bottom-squarks decay into a $b$-quark and the second-lightest neutralino, $\tilde{b}_{1} \rightarrow b + \tilde{\chi}^{0}_{2}$. Each $\tilde{\chi}^{0}_{2}$ is assumed to subsequently decay with 100% branching ratio into a Higgs boson ($h$) like the one in the Standard Model and the lightest neutralino: $\tilde{\chi}^{0}_{2} \rightarrow h + \tilde{\chi}^{0}_{1}$. The $\tilde{\chi}^{0}_{1}$ is assumed to be the lightest supersymmetric particle (LSP) and is stable. Two signal mass configurations are targeted: the first has a constant LSP mass of 60 GeV; and the second has a constant mass difference between the $\tilde{\chi}^{0}_{2}$ and $\tilde{\chi}^{0}_{1}$ of 130 GeV. The final states considered contain no charged leptons, three or more $b$-jets, and large missing transverse momentum. No significant excess of events over the Standard Model background expectation is observed in any of the signal regions considered. Limits at the 95% confidence level are placed in the supersymmetric models considered, and bottom-squarks with mass up to 1.5 TeV are excluded.

144 data tables

Distributions of ${E}_{\mathrm{T}}^{\mathrm{miss}}$ after the background-only fit. The backgrounds which contribute only a small amount (diboson, W+jets and ttbar+W/Z/h) are grouped and labelled as `Other'.

Distributions of ${E}_{\mathrm{T}}^{\mathrm{miss}}$ after the background-only fit. The backgrounds which contribute only a small amount (diboson, W+jets and ttbar+W/Z/h) are grouped and labelled as `Other'.

Distributions of ${E}_{\mathrm{T}}^{\mathrm{miss}}$ after the background-only fit. The backgrounds which contribute only a small amount (diboson, W+jets and ttbar+W/Z/h) are grouped and labelled as `Other'.

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