DPF2015. Search for Chargino and Neutralino using Two Jets in Vector-Boson-Fusion Topology at CMS

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1 DPF5 Search for Chargino and Neutralino using Two Jets in Vector-Boson-Fusion Topology at CMS Andrés Flórez - Uniandes (COL) On behalf of the CMS Collaboration August 4, 5 Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

2 Outline Motivation Electroweak SUSY Searches Probing SUSY with VBF (CMS-SUS-45) Summary Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

3 Motivation Motivation The aim of the talk is to show the first results from CMS on SUSY searches in the electroweak sector, using a VBF-like topology. The VBF topology includes forward jets with a large η gap in opposite hemispheres of the detector. VBF SUSY provides a new handle to search for new physics in compressed mass-spectra scenarios where the τ and the LSP ( ) are nearly mass degenerate, which is important to prove models that include co-annihilation. Co-annihilation plays an important roll in several thermal dark matter (DM) scenarios in order to obtain the correct relic dark matter density predicted by cosmology. Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

4 Motivation Classic SUSY Searches Initial SUSY searches focused on the color sector. These type of signatures have final states with: + jets + leptons(photons) E miss T Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 4 / 5

5 Motivation Dark Matter & Cosmology It is important to directly probe the electroweak SUSY sector Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 5 / 5

6 Electroweak SUSY Searches Searches in the color sector have not yield positive signs of SUSY until now. SUSY searches in the electroweak (EWK) sector open a different avenue to find new physics: Smaller predicted cross sections but lower levels of hadronic activity Complements the color searches The discovery of the Higgs opens up new SUSY searches: Lightest neutral CP even Higgs (h) expected to be SM like, if others are heavy. ± and decay to h+lsp (RPC models) or V (W /Z) + ( LSP) Would provide evidence for SUSY solution to hierarchy problem. Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 6 / 5

7 Third Generation EWK-SUSY Searches (CMS-SUS-6) The experimental sensitivity in final states containing third generation particles is limited, especially in compressed spectra scenarios. Lian Tao and Marcela Carena Ω h <σ anν> dx Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 7 / 5

8 Probing SUSY with VBF (CMS-SUS-45) Probing SUSY with VBF (CMS-SUS-45) Eight final states: µµjj, eµjj, µτ h jj, τ h τ h jj (OS & LS). For the µµjj, eµjj, µτ h jj channels we use an inclusive single muon trigger, while for the τ h τ h jj channels we use a di-tau trigger. Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 8 / 5

9 Probing SUSY with VBF (CMS-SUS-45) Event Selection Criteria (CMS-SUS-45) Summary of the event selection criteria for the different final states considered in the analysis. Note the selections for the µµjj and eµjj channels are presented in one column (l (e/µ) µjj) as they are very similar. Cut l (e/µ) µjj µτ h jj τ h τ h jj Central Selections Trigger Iso µ p T > 4 GeV Iso µ p T > 4 GeV Double τ p T > 45 GeV p T (µ)[gev ] p T (e)[gev ] 5 only eµjj p T (τ h )[GeV ] 45 η(l µ,e,τh ) <. <. <. N b tag jets (CSVL) ET miss [GeV] > 75 > 75 > p T (jets)[gev ] /5 5 η(jets) R(l e,µ,τ, l h e,µ,τ ) h... R(jet, l e,µ,τh )... VBF Selections η(jet, jet ) > 4. > 4. > 4. η jet η jet < < < mj, j[gev ] We perform a shape-based analysis, using the m jj distribution as a discrimination variable. Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 9 / 5

10 Probing SUSY with VBF (CMS-SUS-45) Background Estimation Strategy (CMS-SUS-45) We use a common BG estimation methodology across channels: We obtain SFs in high purity CRs to correct for any mismodeling in simulation, after applying central selections (No VBF selections). When possible, we measure the VBF efficiency from data. The contribution of a given BG in the SR, estimated with the method described above, is performed using the following formula: N Data BG = NMC CR BG (central) SFcentral ɛcr VBF (m jj) 4 A closure test is performed in MC. The difference between the nominal and predicted yields in the closure test, is taken as a systematic error. 5 When possible we also perform closure tests with data. 6 We check that the signal contamination in the CRs is negligible. If the BGs are small, when possible we first show that the VBF shapes are well modelled in simulation and then simply correct the MC prediction with a SF: N Data BG = NMC BG (SR) SF CR central Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

11 Probing SUSY with VBF (CMS-SUS-45) t t Background Estimation For OS/LS µµ (CMS-SUS-45) t t is the largest BG source for both µµ channels (OS & LS) The estimation of this BG is done in a semi-data-driven way. Three CRs are used: CR: SFcentral CR for central selections for OS events. CR: SFcentral CR for central selections for LS events. CR: measure VBF efficiency and dijet mass shape from data. Top Pair Background Estimation & Validation/Closure Strategy q *q N(b) N(b) CR CR CR OS Isolation OS SIGNAL Isolation w/ iso w/o iso w/ iso w/o iso N(b) N(b) LS CR CR Isolation LS SIGNAL CR Isolation w/ iso w/o iso 5 w/ iso w/o iso m( j, j) Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

12 Probing SUSY with VBF (CMS-SUS-45) m jj Distributions (CMS-SUS-45) Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data Higgs Diboson DY+jets W+jets tt pp jj (m ± = GeV, m =m τ µµ (Like charge) = 95 GeV, m = GeV) m(j,j) [GeV] Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data DY+jets W+jets QCD tt Others pp jj (m ± = GeV, m =m τ µµ, eµ, µτ, h = 95 GeV, m τ h τ h = GeV) m(j,j) [GeV] The band includes the total systematic and statistical uncertainties. Correlations across BGs and across channels have been considered. The largest source of systematic uncertainty comes from closure tests in simulation for the BG estimates. Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

13 Probing SUSY with VBF (CMS-SUS-45) Final yields: OS Channels (CMS-SUS-45) Number of observed events in data and estimated background rates for the OS search channels. The uncertainties are based on the number of observed events in the CRs as well as the statistics in simulation. Process µ ± µ jj e ± µ jj µ ± τ h jj τ ± h τ h jj DY + jets 4. ±.7.7± ±.9. ± 4.4 W + jets <. 4.± ±.. ±.7 VV.8 ±.5. ±.7.9 ±.5.5 ±. t t 4. ±.7 9.±..4.7 ±.8 QCD 6. ±.8 Higgs. ±.. ±.5. ±. VBF Z.7 ±. Total. ±.4.± ± 5..9 ± 5. Observed 4 Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

14 Probing SUSY with VBF (CMS-SUS-45) Final yields: LS Channels (CMS-SUS-45) Number of observed events in data and estimated background rates for the LS channels. The uncertainties are based on the number of observed events in the CRs as well as the statistics in simulation. Process µ ± µ ± jj e ± µ ± jj µ ± τ ± h jj τ ± h τ ± h jj DY + jets <. ±.7.5 ±. <. W + jets. ± 8. 4 ±. 9. ±..5 ±. VV. ±..9±.4.. ±.. ± 6.5 t t. ±..5± ±.8. ±. Single top <. QCD 7.6 ±.9 Higgs <. Total 5.4 ±. 5.4± ± ±.9 Observed Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 4 / 5

15 Probing SUSY with VBF (CMS-SUS-45) SUSY Scenario Compressed Mass Spectra & Large Mass Gaps Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 5 / 5

16 Probing SUSY with VBF (CMS-SUS-45) SUSY Scenario Compressed Mass Spectra & Large Mass Gaps (CMS-SUS-45) Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 6 / 5

17 Probing SUSY with VBF (CMS-SUS-45) ± Results - Combined Limits: Scenario (CMS-SUS-45) No excess above the SM background is observed. A combined observed upper bound limit of 8 GeV and an expected limit on 95 GeV is set, for the large mass gap scenario where the mass difference between the chargino and the slepton is 5 GeV and the LSP mass is GeV. For the compressed mass spectra scenario, where the mass difference between the chargino and the LSP is 5 GeV, we set a combined observed upper bound limit of 7 GeV and an expected limit of 8 GeV. σ [fb] - CMS Preliminary 9.7 fb (8 TeV) ± τ ν, τ τ, τ µµ, eµ, µτ h, τ h τ h Observed Expected ± σ, m Expected ± σ, m σ(pp jj) (LO) m ± - m = GeV - m τ = 5 GeV = 5 GeV ± = m [GeV] Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 7 / 5 m

18 Probing SUSY with VBF (CMS-SUS-45) ± Results - Combined Limits: Scenario (CMS-SUS-45) No excess above the SM background is observed. A combined observed upper bound limit of GeV and an expected limit on GeV is set, for the compressed mass spectra scenario. We do not have sensitivity to exclude any masses in the large mass gap scenario, for this slepton mass definition. σ [fb] - CMS Preliminary 9.7 fb (8 TeV) ± τ ν, τ τ, τ µµ, eµ, µτ h, τ h τ h Observed Expected ± σ, m Expected ± σ, m σ(pp jj) (LO) m τ - m = GeV = m = 5 GeV ± = m [GeV] m + m ± Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 8 / 5

19 Probing SUSY with VBF (CMS-SUS-45) Latest Limits in the Electroweak SUSY Sector LSP mass [GeV] ± production CMS Preliminary s = 8 TeV ICHEP 4 - SUS fb - SUS fb Observed Expected m ± = m m ± = m +m Z ± (H )(W ) ± (Z )(W ) ± ~ + - ( l L, BF(l l )=.5 ) + - ~ + - ( l L, BF(l l )= ) ± ( τν τ ) ± ~ + - ( l R, BF(l l )= ) m ± = m +m H neutralino mass = chargino mass [GeV] Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 9 / 5

20 Summary Summary The first VBF SUSY search from CMS is been presented. The search is a promising avenue to target compressed-mass-spectra scenarios with taus. Stay tuned for the next run of the LHC! Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

21 Summary BACKUP Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

22 Summary Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data Higgs Diboson DY+jets W+jets tt pp jj (m ± = GeV, m = 95 GeV, m = GeV) =m τ µµjj - m jj Distributions (CMS-SUS-45) µµ (Opposite charge) m(j,j) [GeV] Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data Higgs Diboson DY+jets W+jets tt pp jj (m ± = GeV, m = 95 GeV, m = GeV) =m τ µµ (Like charge) m(j,j) [GeV] Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

23 Summary Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data Higgs Diboson DY+jets W+jets tt pp jj (m ± = GeV, m = 95 GeV, m = GeV) =m τ eµjj - m jj Distributions (CMS-SUS-45) eµ (Opposite charge) m(j,j) [GeV] Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data Higgs Diboson tt pp jj (m =m ± = GeV, m τ = 95 GeV, m = GeV) eµ (Like charge) m(j,j) [GeV] Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 / 5

24 Summary Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data Diboson DY+jets W+jets tt pp jj (m ± = GeV, m = 95 GeV, m = GeV) =m µτ h τ µτ h jj - m jj Distributions (CMS-SUS-45) (Opposite charge) m(j,j) [GeV] Events / 5 GeV Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) data Diboson DY+jets W+jets tt pp jj (m ± = GeV, m = 95 GeV, m = GeV) =m µτ h τ (Like charge) m(j,j) [GeV] Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 4 / 5

25 Summary Events / 5 GeV 6 data Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) Higgs Diboson VBF-Z DY+jets W+jets QCD pp jj (m ± =m = GeV, m = 95 GeV, m = GeV) τ τ h τ h jj - m jj Distributions (CMS-SUS-45) (Opposite charge) τ h τ h m(j,j) [GeV] Events / 5 GeV 6 data 5 VBF-Higgs Diboson DY+jets 4 W+jets Single-Top tt Obs./Prediction CMS Preliminary 9.7 fb (8 TeV) QCD pp jj (m ± =m = GeV, m = 95 GeV, m = GeV) τ (Like charge) τ h τ h m(j,j) [GeV] Andrés Flórez (Uniandes - Colombia) DPF5 August 4, 5 5 / 5