Abstract
A search for excited electrons produced in pp collisions at $$\sqrt{s}$$s = 13 $$\text {Te}\text {V}$$Te via a contact interaction $$q{\bar{q}}\rightarrow ee^*$$qq¯→ee∗ is presented. The search uses 36.1 fb$$^{-1}$$-1 of data collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider. Decays of the excited electron into an electron and a pair of quarks ($$eq{\bar{q}}$$eqq¯) are targeted in final states with two electrons and two hadronic jets, and decays via a gauge interaction into a neutrino and a $$W$$W boson ($$\nu W$$νW) are probed in final states with an electron, missing transverse momentum, and a large-radius jet consistent with a hadronically decaying $$W$$W boson. No significant excess is observed over the expected backgrounds. Upper limits are calculated for the $$pp \rightarrow ee^*\rightarrow eeq{\bar{q}} $$pp→ee∗→eeqq¯ and $$pp \rightarrow ee^*\rightarrow e\nu W $$pp→ee∗→eνW production cross sections as a function of the excited electron mass $$m_{e^*}$$me∗ at 95% confidence level. The limits are translated into lower bounds on the compositeness scale parameter $$\Lambda $$Λ of the model as a function of $$m_{e^*}$$me∗. For $$m_{e^*} <0.5$$me∗<0.5 $$\text {Te}\text {V}$$Te, the lower bound for $$\Lambda $$Λ is 11 $$\text {Te}\text {V}$$Te. In the special case of $$m_{e^*} =\Lambda $$me∗=Λ, the values of $$m_{e^*} <4.8$$me∗<4.8 $$\text {Te}\text {V}$$Te are excluded. The presented limits on $$\Lambda $$Λ are more stringent than those obtained in previous searches.