Search for the direct production of charginos and neutralinos in s√ = 13 TeV pp collisions with the ATLAS detector

Abstract

A search for the direct production of charginos and neutralinos in final states with at least two hadronically decaying tau leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 36.1 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 Standard Model background expectation is observed. Limits are derived in scenarios of χ̃+1χ̃−1 pair production and of χ̃±1χ̃02 and χ̃+1χ̃−1 production in simplified models where the neutralinos and charginos decay solely via intermediate left-handed staus and tau sneutrinos, and the mass of the τ̃L state is set to be halfway between the masses of the χ̃±1 and the χ̃01. Chargino masses up to 630 GeV are excluded at 95% confidence level in the scenario of direct production of χ̃+1χ̃−1 for a massless χ̃01. Common χ̃±1, χ̃02 masses up to 760 GeV are excluded in the case of production of χ̃±1χ̃02 and χ̃+1χ̃−1 assuming a massless χ̃01. Exclusion limits for additional benchmark scenarios with large and small mass-splitting between the χ̃±1 and the χ̃01 are also studied by varying the τ̃L mass between the masses of the χ̃±1 and the χ̃01.