Reinterpretation of searches for supersymmetry in models with variable R-parity-violating coupling strength using the full ATLAS Run 2 Dataset

Abstract

A collection of thirteen ATLAS searches for supersymmetry (SUSY) models, optimized for R-parity-conserving (RPC) and R-parity-violating (RPV) SUSY, are reinterpreted in SUSY models with variable RPV coupling strength, which determines whether the lightest supersymmetric particle decays promptly or is long-lived. The dataset corresponds to an integrated luminosity of 140 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV collected between 2015 and 2018 by the ATLAS detector at the Large Hadron Collider. Limits are set at 95% confidence level on the mass of pair-produced gluinos decaying to final states enhanced or depleted with top quarks, and on the masses of pair-produced top squarks, tau-sleptons, or charginos and neutralinos. In a model of pair-produced gluinos decaying to final states enhanced with top quarks, a lower limit of 1.8 TeV on the gluino mass is set regardless of the RPV coupling value. In the gluino model with decays to first and second generation quarks, gluino masses are excluded up to 1.6-2.2 (1.6-2.5) TeV for different values of the RPV coupling $λ^{'}$ ($λ^{''}$). Top-squark masses up to 2.4 TeV are excluded at high values of $λ^{''}$, compared to 1.0-1.7 TeV for low and intermediate $λ^{''}$. Tau-slepton masses between 180 GeV and 340 GeV are excluded for $λ$ couplings smaller than $10^{-4}$. Higgsino masses up to 800 GeV-1.0 TeV are excluded when $λ_{i33}$ is larger than $4\times10^{-5}$. This work extends the analyses beyond RPC scenarios to a broad class of RPV frameworks and achieves significantly improved sensitivity to a diverse range of long-lived particle signatures.

Figures (8)

• Figure 7: Impact of neutralino decays with different lifetimes on the \ref{['fig:variables_a']} number of light leptons ($\ell$), \ref{['fig:variables_b']} number of hadronically-decaying $\tau$-leptons ($\Pgt_{\text{had}}$), \ref{['fig:variables_c']} number of jets, \ref{['fig:variables_d']} the $H_\mathrm{T}$, \ref{['fig:variables_e']} number of $b$-jets and \ref{['fig:variables_f']}$E_{\text{T}}^{\text{miss}}$. All observables are shown at the reconstruction level with full simulation of the ATLAS detector. In (a) and (b), the stau model with non-zero $\lambda_{133}$ is shown. If the branching fraction (B) is specified, the gluino and $\tau$-slepton can decay directly to SM particles or via a prompt LSP decay. In (c) and (d) the Gqq+UDD model with non-zero $\lambda"\xspace_{112}$ is shown. In (e) and (f), the Gtt model with non-zero $\lambda"\xspace_{323}$ is shown.
• Figure 8: The $b$-tagging efficiency for \ref{['fig:bjet_frac']} displaced $b$-jets (HF) as a function of the position of the $B$-hadron decay vertex in the transverse plane ($L^{\prime}_{xy}$) and \ref{['fig:ljet_frac']} displaced light-flavor jets (LF) as a function of the transverse LLP decay position ($L_{xy}$). The efficiency is shown separately for jets where the $B$-hadron or light-flavor quark direction is collinear (in-core) or is not collinear (off-core) with the LLP direction. The prompt sample shown in \ref{['fig:bjet_frac']} is from $b$-jets in a $t\bar{t}$ sample, while the HF shown in \ref{['fig:ljet_frac']} is a combination of in-core and off-core displaced HF jets. The bottom panel shows the ratio of the $b$-tagging efficiencies for \ref{['fig:bjet_frac']} displaced HF jets and prompt $b$-jets in a $t\bar{t}$ sample, and for \ref{['fig:ljet_frac']} displaced light-flavor jets to displaced HF jets. The function drawn in \ref{['fig:bjet_frac']} is used to derive the uncertainties for off-core HF jets.
• Figure 9: Exclusion limits for the Gqq+LQD model as a function of $\lambda'\xspace_{111}$ and $m(\tilde{g}\xspace)$ under the assumption that $\lambda'\xspace_{111}=\lambda'\xspace_{211}$. Expected limits are shown with dashed lines, and observed as solid. The RPC-limit is shown on the leftmost part of the axes. The region $\lambda^{\prime}_{111}$ greater than 2.91 is forbidden by constraints on the $0\nu\beta\beta$ measurements Allanach:1999ic. The exclusion limits are derived assuming the squark masses listed in Table \ref{['tab:Modelsummary']}.
• Figure 10: Exclusion limits for the Gqq+UDD model as a function of $\lambda"\xspace_{112}$ and $m(\tilde{g}\xspace)$. Expected limits are shown with dashed lines, and observed as solid. The RPC-limit is shown on the leftmost part of the axes. The region $\lambda"\xspace_{112}>1.25$ is forbidden by constraints from the renormalization group equations. The exclusion limits are derived assuming the squark masses listed in Table \ref{['tab:Modelsummary']}.
• Figure 11: Exclusion limits for the Gtt model as a function of $\lambda"\xspace_{323}$ and $m(\tilde{g}\xspace)$. Expected limits are shown with dashed lines, and observed as solid. The region $\lambda"\xspace_{323} > 1.07$ is forbidden by constraints from the renormalization group equations. The exclusion limits are derived assuming the squark masses listed in Table \ref{['tab:Modelsummary']}.