Direct electroweakino, slepton and stop searches at CMS Lukas - PowerPoint PPT Presentation

Direct electroweakino, slepton and stop searches at CMS Lukas Vanelderen (University of Hamburg) on behalf of the CMS collaboration 29.05.13, ECFA LC2013 0/21 0/21

Direct production of stops 1/21

CMS stop searches main challenge: ◮ small stop mass: large cross section but signal looks like bkg ◮ large stop mass: different kinematics, but small cross section 7 TeV results: ◮ SUS-11-030: all-hadronic channel, jets and MET, 5/fb ◮ SUS-12-009: all-hadronic channel, razor, 5/fb 8 TeV results: ◮ SUS-12-023: single-lepton channel, 9.7/fb ◮ SUS-13-003: RPV, ≥ 3 leptons, 19.5/fb ◮ SUS-13-011: single lepton channel, 19.5/fb → THIS TALK 2/21

Event pre-selection b P 2 W + t ˜ ◮ 1 iso e /µ , p T > 30 / 25 GeV t χ 0 ˜ 1 ◮ 2nd lepton veto: χ 0 ˜ 1 ˜ t ∗ - no loose e /µ W − P 1 ¯ t - no iso track ¯ b b - no had tau W + ◮ ≥ 4 jets, p T > 30 GeV, | η | < 2 . 4 P 2 χ + ˜ χ 0 ˜ 1 ◮ 1 of which is b -tagged ˜ t χ − χ 0 ˜ ˜ 1 P 1 ◮ MET > 100 GeV ˜ t ∗ W − ¯ b 3/21

Discriminating variables ∫ -1 ∫ -1 ∫ -1 CMS Preliminary s = 8 TeV, Ldt = 19.5 fb CMS Preliminary s = 8 TeV, Ldt = 19.5 fb CMS Preliminary s = 8 TeV, Ldt = 19.5 fb 2 2 2 Data/MC Data/MC Data/MC 1.5 1.5 1.5 1 1 1 0.5 0.5 0.5 0 0 0 Entries / 30 GeV Entries / 25 GeV Entries / 25 GeV Pre-selection Data Pre-selection Data Pre-selection Data 6 10 6 1 top 1 top 1 top 10 l 6 l l 10 M W → → → M T t t ll MET t t ll t t ll 5 10 W+jets W+jets W+jets 5 T 2 5 10 10 rare rare rare ~ ∼ ~ ∼ 4 ~ ∼ → χ 0 → χ 0 10 → χ 0 t t (650/50) x1000 t t (650/50) x1000 t t (650/50) x1000 1 1 1 4 10 4 10 3 10 3 10 3 10 10 2 2 10 2 10 10 10 1 10 0 50 100 150 200 250 300 100 150 200 250 300 350 100 150 200 250 300 350 400 450 500 M [GeV] miss W E [GeV] M [GeV] T T T2 ∫ ∫ ∫ -1 -1 -1 CMS Preliminary s = 8 TeV, Ldt = 19.5 fb CMS Preliminary s = 8 TeV, Ldt = 19.5 fb CMS Preliminary s = 8 TeV, Ldt = 19.5 fb 2 2 2 Data/MC Data/MC Data/MC 1.5 1.5 1.5 1 1 1 0.5 0.5 0.5 0 0 0 7 Entries / 0.04 Entries / 15 GeV Entries / 0.33 10 7 10 Pre-selection Data Pre-selection Data Pre-selection Data 6 1 l top 10 6 1 l top 10 1 l top 6 10 H ratio → p T ( b 1 ) → ∆ R ( l , b 1 ) → t t ll t t ll t t ll 5 W+jets 10 5 W+jets 5 W+jets 10 T 10 rare rare rare ~ ∼ 4 ∼ ∼ → χ 0 10 ~ → χ ± ~ → χ ± 4 t t (650/50) x1000 t b (650/50/0.5) x1000 4 t b (650/50/0.5) x1000 10 10 1 1 1 3 10 3 10 3 10 2 2 10 10 2 10 10 10 10 1 1 1 -1 -1 10 10 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 50 100 150 200 250 300 350 400 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 ∆ ratio p (b ) [GeV] R( l , b ) H T T 1 1 4/21

Signal regions ◮ M T > 120 GeV ◮ cut on BDT output, multiple BDTs trained for particular stop scenarios: b b P 2 W + t W + P 2 ˜ t χ 0 χ + ˜ ˜ χ 0 ˜ 1 1 ˜ t χ 0 ˜ χ − χ 0 ˜ ˜ 1 1 t ∗ ˜ P 1 t ∗ ˜ W − W − P 1 ¯ t ¯ ¯ b b m ˜ 1 = m ˜ 1 + x ( m ˜ t − m ˜ 1 ) χ ± χ 0 χ 0 + → bW  600 � Δ M = m top �   t → b  0 (x=0.5) t → t  0 600 � χ 1 χ 1 χ 1 Δ M = M W � m 𝛙 [GeV] � m 𝛙 [GeV] � 500 � � 500 � ) p o t x = 0 . 5 l l 400 � e h � � 400 � 0 � 1 � s ) ) M M 2 (medium Δ M) � ~ � - 0 � 1 � f Δ Δ f ~ � o 300 � ( w m ) � M 5 o 300 � u Δ ( l i d � w 2 ) e M o 3 (high Δ M) � m l Δ ( 200 � 1 ( 3 h 200 � g 1 (low mass) � h i ( 100 � 4 100 � 200 300 400 500 600 700 � m t [GeV] � ~ � 200 300 400 500 600 700 � m t [GeV] � ~ � more BDTs for x = 0 . 25 , 0 . 75 5/21

Results ∫ ∫ -1 -1 CMS Preliminary s = 8 TeV, Ldt = 19.5 fb CMS Preliminary s = 8 TeV, Ldt = 19.5 fb 2 2 Data/MC Data/MC 1.5 1.5 1 1 0.5 0.5 0 0 Entries / 60 GeV Entries / 0.05 ∼ ∼ ~ ~ → χ 0 Data → χ 0 Data M T , pass BDT5 BDT5, M T > 120 t t BDT5 t t BDT5 1 1 1 l top 600 1 l top 3 10 → → t t ll t t ll W+jets 500 W+jets rare rare 400 2 10 300 10 200 100 1 0 100 200 300 0 0.2 0.4 0.6 M [GeV] BDT Output T no excess observed, we proceed with SMS interpretation... 6/21

˜ χ 0 t → t ˜ 1 b ∫ -1 CMS Preliminary s = 8 TeV, Ldt = 19.5 fb 2 P 2 10 [GeV] upper limit [pb] W + t ~ ~ ~ ∼ ± σ theory 400 → → χ 0 Observed ( 1 ) pp t t *, t t ˜ 1 t ± σ Expected ( 1 ) χ 0 BDT analysis ˜ 1 350 10 unpolarized top -1 Observed (9.7 fb ) 0 1 ∼ χ χ 0 ˜ m = M W = M t 300 1 t ∗ ˜ - m ∼ 0 - m ∼ 0 χ χ 1 1 W − 1 250 P 1 t ¯ ~ ~ m m t t σ ¯ 200 b -1 10 150 ◮ unpolarized top 100 -2 10 ◮ results from 6 BDTs 50 ◮ per point, use most -3 0 10 200 300 400 500 600 700 800 sensitive signal region m [GeV] ~ t 7/21

˜ ∫ χ ± -1 CMS Preliminary s = 8 TeV, Ldt = 19.5 fb t → b ˜ 2 10 [GeV] upper limit [pb] 1 ∼ theory ~ ~ ~ ± σ 400 → → χ + Observed ( 1 ) pp t t *, t b 1 ± σ Expected ( 1 ) BDT analysis 350 10 -1 Observed (9.7 fb ) 0 1 ∼ χ m 300 x=0.5 1 250 W = m b σ 200 ∼ 0 - m χ 1 -1 10 W + ± ∼ 150 m χ 1 P 2 χ + ˜ χ 0 ˜ 100 1 -2 ˜ 10 t χ − χ 0 50 ˜ ˜ 1 P 1 t ∗ ˜ -3 0 10 200 300 400 500 600 700 800 W − m [GeV] m = 0.5 m + 0.5 m ∼ ± ~ ∼ ~ χ χ 0 t t ¯ b 1 1 ∫ -1 CMS Preliminary s = 8 TeV, Ldt = 19.5 fb 2 10 [GeV] upper limit [pb] ~ ~ ~ ∼ ± σ theory + Observed ( 1 ) 400 → → χ pp t t *, t b ◮ results from 4 BDTs 1 ± σ BDT analysis Expected ( 1 ) 350 10 ◮ per point, use most 0 1 ∼ χ m x=0.75 300 sensitive signal region 1 250 m W = σ 200 m ∼ 0 χ 1 ◮ unpolarized top - -1 ∼ ± 10 m χ 1 150 ◮ m ˜ 1 = m ˜ 1 + x ( m ˜ t − m ˜ 1 ) χ ± χ 0 χ 0 100 -2 10 50 -3 0 10 350 400 450 500 550 600 650 700 750 800 m [GeV] m = 0.25 m + 0.75 m ∼ ∼ ~ ± ~ 0 χ χ t t 8/21 1 1

Impact of polarization ◮ different scenarios tested for - top polarization, χ ± χ 0 - chargino polarization and W ˜ 1 ˜ 1 coupling ◮ accomodates for different stop and ewkino mixing scenarios ◮ typical impact on limits ± 20 GeV ∫ ∫ -1 -1 CMS Preliminary s = 8 TeV, Ldt = 19.5 fb CMS Preliminary s = 8 TeV, Ldt = 19.5 fb [GeV] [GeV] ~ ~ ~ ∼ ~ ~ ~ ∼ → → χ 0 Observed (unpolarized top) → → χ + Observed (nominal) 400 pp t t , t t 400 pp t t *, t b 1 1 ∼ ± ∼ ∼ ± χ χ 0 χ Observed (right-handed top) Observed ( , right W ) BDT analysis BDT analysis R 1 1 ∼ ± ∼ ∼ ± 350 350 χ χ 0 χ Observed (left-handed top) Observed ( , left W ) R 1 1 0 1 0 1 ∼ ∼ ∼ ∼ χ ∼ χ χ ± χ 0 χ ± Observed ( , right W ) m m L 1 1 300 300 ∼ ∼ ∼ m W m χ ± χ 0 χ ± t Observed ( , left W ) L 1 1 = = ∼ 0 ∼ 0 = m W 250 m χ m χ 250 1 1 - - ~ ~ m m t t 0 - m ∼ 200 200 χ 1 ∼ ± m χ 150 150 1 100 100 50 50 0 0 200 300 400 500 600 700 800 200 300 400 500 600 700 800 m = 0.5 m + 0.5 m m [GeV] ∼ ± ~ ∼ m [GeV] χ χ 0 ~ t ~ t t 1 1 9/21

Direct production of ewkinos and sleptons 10/21

CMS ewkino and slepton searches ◮ low cross sections compared to strong production ◮ but might dominate if squarks and gluinos are heavy ◮ CMS results from 5/fb at 7TeV: JHEP11(2012)147, arXiv:1209.6620 ◮ CMS results from 9.2/fb at 8TeV: CMS-SUS-12-022 → THIS TALK 11/21

Targetted topologies χ ± χ ± χ ± χ 0 1 , ˜ l ˜ χ 0 χ 0 production of ˜ 1 ˜ 2 , ˜ 1 ˜ l , ˜ 2 ˜ 2 ◮ w/ and w/o intermediate sparticles ◮ w/ and w/o on-shell W / Z ℓ Z ℓ χ 0 ˜ p 2 2 χ 0 p 2 ˜ χ 0 χ 0 2 ˜ ˜ ˜ ℓ 1 1 χ 0 ˜ ˜ ℓ 1 p 1 χ ± p 1 χ 0 ˜ ˜ χ ± 1 ˜ 1 ℓ 1 ν W ℓ ℓ ν ˜ ℓ P 2 χ 0 ˜ P 2 1 ν ˜ χ 0 ˜ 1 χ ± ˜ χ 0 ˜ ˜ χ 0 ℓ ˜ 1 P 1 P 1 ˜ 1 χ ∓ ℓ ˜ ℓ ν ℓ search in a variety of lepton + MET channels 12/21