Search for new physics in same-sign dilepton events in proton–proton collisions at $$\sqrt{s} = 13\,\text {TeV} $$ s = 13 TeV

Abstract

A search for new physics is performed using events with two isolated same-sign leptons, two or more jets, and missing transverse momentum. The results are based on a sample of proton–proton collisions at a center-of-mass energy of 13 recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 2.3 . Multiple search regions are defined by classifying events in terms of missing transverse momentum, the scalar sum of jet transverse momenta, the transverse mass associated with a boson candidate, the number of jets, the number of quark jets, and the transverse momenta of the leptons in the event. The analysis is sensitive to a wide variety of possible signals beyond the standard model. No excess above the standard model background expectation is observed. Constraints are set on various supersymmetric models, with gluinos and bottom squarks excluded for masses up to 1300 and 680, respectively, at the 95 % confidence level. Upper limits on the cross sections for the production of two top quark-antiquark pairs (119) and two same-sign top quarks (1.7) are also obtained. Selection efficiencies and model independent limits are provided to allow further interpretations of the results.

Search for supersymmetry in final states with two same-sign or three leptons and jets using 36 fb−1 of $$ \sqrt{s}=13 $$ TeV pp collision data with the ATLAS detector

“…It is an extension of an earlier search performed by the ATLAS experiment [22] with √ s = 13 TeV data [23], and uses the data collected in proton-proton (pp) collisions during 2015 and 2016. Similar searches for SUSY in this topology were also performed by the CMS experiment at √ s = 13 TeV [24][25][26]. While the same-sign or three-lepton signatures are present in many scenarios of physics beyond the SM (BSM), SM processes leading to such final states have very small cross-sections.…”

Naturalness confronts nature: searches for supersymmetry with the CMS detector in pp collisions at √s = 8 and $13$ TeV

“…7 In early 2015, the LHC restarted pp collisions at a collision energy of 13 TeV after two years of maintenance and upgrades. The increase in centerof-mass energy from 8 to 13 TeV provides an opportunity to significantly extend the sensitivity of LHC searches to higher SUSY particle masses [204,205,96,206,207,208,209,210,211,212,213,214,215,216]. In particular, the largest gain in sensitivity is expected for gluinos, which would be produced almost 50 times more often at 13 TeV than at 8 TeV for a gluino mass of 1.6 TeV.…”

LHC signals of a heavy doublet Higgs as dark matter portal: cut-based approach and improvement with gradient boosting and neural networks

“…Signal: The signal here is a pair of same-sign leptons (e/µ) + 2 jets + / E T . This signal has been searched for in the LHC [49]. It reports no significant excess over the SM expectation with Ldt = 36f b −1 at 95% C.L.…”

“…The dominant backgrounds for this final state are [49] • tt semileptonic decay which leads to non-prompt leptons in the final state. Nonprompt leptons are those which can arise from heavy flavor decay or hadrons being misidentified as leptons etc.…”