Search for SUSY in events with one lepton

Search for SUSY in events with one lepton, jets and MET in CMS at √s=13 Te. V Artur Apresyan on behalf of CMS Collaboration 38 th International Conference on High Energy Physics 04/09/2016

Searches with one lepton in final state • Sensitivity to production of gluinos, stops and EWK SUSY • Presence of a well identified lepton helps to reduce hadronic backgrounds – Main backgrounds: ttbar and W+jets, QCD • Signatures with multiple tops: large fraction of signals have ≥ 1 lepton 2 A. Apresyan | ICHEP 2016

SUS-16 -019 Gluino search with 1 -lepton • Main backgrounds from ttbar and W+jets • Exploit the difference in W decay kinematics Δφ lepton Δφ W Δφ is spread out in signal, due to LSP Δφ is small for backgrounds 3 A. Apresyan | ICHEP 2016

Gluino search with 1 -lepton • Main backgrounds from ttbar and W+jets • Exploit the difference in W decay kinematics Events with many b-jets 4 A. Apresyan Events with 0 b-jets | ICHEP 2016 SUS-16 -019

SUS-16 -019 Event selections • Event selection: – Exactly 1 electron or muon p. T > 25 Ge. V – ≥ 5 (0 -b) or ≥ 6 (multi-b) anit-kt jets – HT > 500 Ge. V; LT > 250 Ge. V • Signal regions defined by sliding Δɸ cut: Δɸ > 0. 5, 0. 75, 1. 0 0 -b, Less jets, SR binned in LT, HT, Δɸ Bkgd: ttbar and W+Jets 5 A. Apresyan | ICHEP 2016 Many b-jets, Many jets, SR binned in LT, HT, Δɸ Bkgd: mostly ttbar

SUS-16 -019 ttbar and W+jets backgrounds • Use low Δφ regions to derive translation factors – Translation factors RCS derived in low Njet sidebands • Extrapolation from low to high Njet obtained from MC 6 A. Apresyan | ICHEP 2016 3 -4/4 -5 jets • Multi-b SR: one RCS for all EWK backgrounds • 0 -b SR: RCS derived separately for W+jets and ttbar: fit Nb shape >5/6 jets Njet signal region RCS sideband x Δφ

SUS-16 -019 ttbar and W+jets backgrounds • Use low Δφ regions to derive translation factors – Translation factors RCS derived in low Njet sidebands 3 -4/4 -5 jets >5/6 jets Njet • Template fit to Nb to extract relative fractions of tt and W+jets 7 A. Apresyan | ICHEP 2016 signal region RCS sideband x Δφ

SUS-16 -019 Results multi-b 0 -b • No significant deviations from data observed in the signal regions 8 A. Apresyan | ICHEP 2016

SUS-16 -019 Results • Exclude gluino masses – T 1 tttt: up to 1. 65 Te. V for neutralino masses ≤ 900 Ge. V – T 5 qqqq. WW: up to 1. 6 Te. V for neutralino masses ≤ 600 Ge. V 9 A. Apresyan | ICHEP 2016

RPV gluino search in 0 - and 1 -leptons • Search for new physics with a high Njets and Nb signature – 0 and 1 lepton final state – No MET requirement – Main backgrounds: QCD and ttbar • Benchmark model is RPV SUSY with gluino tbs – Using 2. 7 fb-1 of 2015 data • Search for excess in Nb distribution – Fit Nb distribution in bins of Nj and MJ 10 A. Apresyan | ICHEP 2016 SUS-16 -013

SUS-16 -013 Event selections • • 0 or 1 lepton with PT > 20 Ge. V ≥ 4 Jets with PT > 30 Ge. V; Nb ≥ 1 HT > 1500 Ge. V (1200 Ge. V) for 0 -lepton (1 -lepton) selection MJ > 500 Ge. V; MJ is re-clustered from R=0. 4 anti-kt jets • Data sample split into control and signal regions based on Nj, Nb, and MJ 11 A. Apresyan | ICHEP 2016

SUS-16 -013 QCD background estimation • Flavor composition of QCD events may not be well-modeled – Template fit to b-tag discriminant shape – Reweight MC with fractions obtained from the fit • Vary the fit range; and fit in sideband to assess systematic uncertainty • Measure the uncertainty from gluon splitting mismodeling – Normalize in high ΔRbb region; and measure mismodeling in low ΔRbb 12 A. Apresyan | ICHEP 2016

SUS-16 -013 Results • Likelihood template fit of Nb distribution in bins of Nj and MJ 13 A. Apresyan | ICHEP 2016

SUS-16 -013 Results • Data is found to be consistent with background expectation • Exclude RPV gluino production with masses below 1360 Ge. V 14 A. Apresyan | ICHEP 2016

SUS-16 -026 EWK SUSY searches • Chargino-netralino production – χ 20 → Hχ 10: Higgs boson in the H bb channel – χ 1± → Wχ 10: W boson leptonic decay • Search performed in Mbb distribution – Extra MET from signal helps to separate backgrounds • Main backgrounds: ttbar and W+jets 15 A. Apresyan | ICHEP 2016

SUS-16 -026 Event selection • Signal region 90 Ge. V < Mbb < 150 Ge. V • Suppress backgrounds – Exactly two b-jets, – 1 -lepton, veto additional leptons – MET > 100 Ge. V, MT > 150 Ge. V, MCT > 150 Ge. V Validate Mbb shape modeling of for 2 l top 16 A. Apresyan Validate tail modeling in W+jets Derive corrections/systematics | ICHEP 2016 Validate tail modeling 2 l top Derive correction/systematics

Background prediction SUS-16 -026 • Backgrounds estimated with MC simulation, – Dilepton top quark: ~90% of total background in SR – Subdominant backgrounds: W+light jets, W+HF, W+Z(bb) • Good modeling of Mbb shape near signal region – Assign stat error (20%) as systematic on modeling of 2 l top 17 A. Apresyan | ICHEP 2016

SUS-16 -026 Results • Data agrees with the prediction in the signal region • Sensitivity close to exclude the models, σ limits around 1 pb 18 A. Apresyan | ICHEP 2016

Summary • Searches for SUSY are entering a new era at 13 Te. V with large datasets – Gluino limits extended ~100 Ge. V beyond previous searches – Nearing sensitivity for EWK SUSY production • Good modeling of SM backgrounds is observed in a variety of dedicated control regions – Robust techniques for SM background estimation • Many improvements in the analysis techniques, many more results to come with quickly increasing datasets 19 A. Apresyan | ICHEP 2016