Search for electroweak production of supersymmetric particles in final states with two τ-leptons in √s = 13 TeV pp collisions with the ATLAS detector

A bstract Three searches for the direct production of τ -sleptons or charginos and neutralinos in final states with at least two hadronically decaying τ -leptons are presented. For chargino and neutralino production, decays via intermediate τ -sleptons or W and h bosons are considered. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 139 fb − 1 , recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. No significant deviation from the expected Standard Model background is observed and supersymmetric particle mass limits at 95% confidence level are obtained in simplified models. For direct production of ~ χ₁⁺~ χ₁⁻ χ ~ 1 + χ ~ 1 − , chargino masses are excluded up to 970 GeV, while ~ χ₁± χ ~ 1 ± and ~ χ₂⁰ χ ~ 2 0 masses up to 1160 GeV (330 GeV) are excluded for ~ χ₁±~ χ₂⁰/~ χ₁⁺~ χ₁⁻ χ ~ 1 ± χ ~ 2 0 / χ ~ 1 + χ ~ 1 − production with subsequent decays via τ -sleptons ( W and h bosons). Masses of τ -sleptons up to 500 GeV are excluded for mass degenerate ~ τL,R τ ~ L , R scenarios and up to 425 GeV for ~ τL τ ~ L -only scenarios. Sensitivity to ~ τR τ ~ R -only scenarios from the ATLAS experiment is presented here for the first time, with ~ τR τ ~ R masses excluded up to 350 GeV.