Search for direct production of electroweakinos in final states with one lepton, jets and missing transverse momentum in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector
G. Aad (CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France); B. Abbott (Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK, United States of America); K. Abeling (II. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany); N. Abicht (Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany); S. Abidi (Physics Department, Brookhaven National Laboratory, Upton, NY, United States of America); et al - Show all 2944 authors
Searches for electroweak production of wino-like chargino pairs, $$ {\overset{\sim }{\chi}}_1^{+}{\overset{\sim }{\chi}}_1^{-} $$ , and of wino-like chargino and next-to-lightest neutralino, $$ {\overset{\sim }{\chi}}_1^{\pm }{\overset{\sim }{\chi}}_2^0 $$ , are presented. The models explored assume that the charginos decay into a W boson and the lightest neutralino, $$ {\overset{\sim }{\chi}}_1^{\pm}\to {W}^{\pm }{\overset{\sim }{\chi}}_1^0 $$ . The next-to-lightest neutralinos are degenerate in mass with the chargino and decay to $$ {\overset{\sim }{\chi}}_1^0 $$ and either a Z or a Higgs boson, $$ {\overset{\sim }{\chi}}_2^0\to Z{\overset{\sim }{\chi}}_1^0 $$ or $$ h{\overset{\sim }{\chi}}_1^0 $$ . The searches exploit the presence of a single isolated lepton and missing transverse momentum from the W boson decay products and the lightest neutralinos, and the presence of jets from hadronically decaying Z or W bosons or from the Higgs boson decaying into a pair of b-quarks. The searches use 139 fb −1 of $$ \sqrt{s} $$ = 13 TeV proton-proton collisions data collected by the ATLAS detector at the Large Hadron Collider between 2015 and 2018. No deviations from the Standard Model expectations are found, and 95% confidence level exclusion limits are set. Chargino masses ranging from 260 to 520 GeV are excluded for a massless $$ {\overset{\sim }{\chi}}_1^0 $$ in chargino pair production models. Degenerate chargino and next-to-lightest neutralino masses ranging from 260 to 420 GeV are excluded for a massless $$ {\overset{\sim }{\chi}}_1^0 $$ for $$ {\overset{\sim }{\chi}}_2^0\to Z{\overset{\sim }{\chi}}_1^0 $$ . For decays through an on-shell Higgs boson and for mass-splitting between $$ {\overset{\sim }{\chi}}_1^{\pm }/{\overset{\sim }{\chi}}_2^0 $$ and $$ {\overset{\sim }{\chi}}_1^0 $$ as small as the Higgs boson mass, mass limits are improved by up to 40 GeV in the range of 200–260 GeV and 280–470 GeV compared to previous ATLAS constraints.