LHC Studies on the Electroweak Sector of MSSM

LHC Studies on the Electroweak Sector of MSSM Shufang Su U. of Arizona, UC Irvine S. Su In collaboration with J. Eckel, W. Shepherd, arxiv:.65; T. Han, S. Padhi, arxiv:.xxxx;

Outline Limitation of current LHC SUSY searches Current exp search limits on MSSM EW sector MSSM electroweak sector Neutralinos/Charginos: production and decay Two analyses: Gauginos and Higgsinos (in slepton decoupling limit Sleptons via gaugino decays Conclusion S. Su

Current LHC SUSY searches: limitations =<ST (GeV/c m / 7 6 5 4 CMS Preliminary & % = LSP Limits q ~ (5GeV Limits tan# =, A q~ (GeV q ~ (75GeV Lepton =, > MT SS Dilepton s = 7 TeV, " Ldt =. fb! T CDF D g~, ~ q, tan#=3, < ± LEP % $ ~ ± LEP l g ~ (5GeV Jets+MHT g~, q ~, tan#=5, < g ~ (GeV 3 OS Dilepton g ~ (75GeV!""#$%&'( *'+',./ +'**'% ' q ~ (5GeV g ~ (5GeV 4 6 8 m (GeV/c =<ST S. Su 3

Current LHC SUSY searches: limitations =<ST msugra mm/ plane? (GeV/c m / 7 6 5 3 CMS Preliminary q ~ (5GeV tan# =, A q~ (GeV 4 Lepton large HT cuts: less sensitive to light particles SS Dilepton & % = LSP Limits Limits starting from gluino/squark production q ~ (75GeV =, > MT OS Dilepton s = 7 TeV, " Ldt =. fb! T CDF D g~, ~ q, tan#=3, < ± LEP % $ ~ ± LEP l g ~ (5GeV Jets+MHT g~, q ~, tan#=5, < g ~ (GeV g ~ (75GeV!""#$%&'( *'+',./ +'**'% ' q ~ (5GeV g ~ (5GeV 4 6 8 m (GeV/c =<ST S. Su 3

LHC vs. Tevatron (GeV/c m / 4 35 3 5 CMS $# = LSP 95% C.L. Limits: CMS LO observed CMS NLO observed CMS NLO expected ± % CMS NLO expected ± % L int = 35 pb, q ~ (65GeV/c tan! = 3, A q ~ (5GeV/c D g~, ~ q, LEP " # ~ ± LEP l ± D " #, " # 5 3 5 5 5 3 m s = 7 TeV ± < g ~ (65GeV/c (GeV/c =, > 4 g ~ (5GeV/c m / (GeV/c % $ B( # 3l (pb 9 8 7 CMS Preliminary 6 5 CMS = 35 pb, s = 7 TeV LEP direct Limit 95% C.L. CLs Limits NLO observed NLO 4 expected median NLO expected ±% 3 NLO observed D Limiṯ L=.3fb q ~ (75GeV L int s = 7 TeV, L 95% = C.L.. Limits: fb int CMS observed CDF g~, ~ q CMS, tan!=5, expected < ± % CMS expected ± % D g~, ~ q, tan!=3, < ± LEP $ # Theory % NLO $ B( # 3l ~ ± LEP l D # ±, # 4 6 8 q~ (5GeV tan&=3, A =, >, m! " ± m =6 GeV/c (GeV/c (GeV/c m / 4 3 RunII: EW χ ± χ production LHC: gluino/squark pair production not a direct limit on mχ ± tan! = 3, A =, > derived from mgluino 5 5 5 3 S. Su 4 m (GeV/c Figure 8: Excluded regions for the CMSSM scenar (right. Values of m, m / below the red curve (obs For comparison the expected limits are shown as we

Motivation Exploring LHC reach for the electroweak sector of MSSM gauginos, Higgsinos and sleptons. DM connection neutralinos: DM candidate sleptons: relevant for DM annihilation process Superpartners of gauge bosons, Higgses, and leptons suffer from small electroweak production more work needs to be done regarding collider searches current SUSY search strategy is not sensitive to lighter EW interacting particles (large HT cuts reduce the signal efficiency Colored superparticle might be very heavy no indication from current LHC search EW sector (+stop/sbottoms might be the only particles accessible at the LHC Connection to Lepton Collider S. Su 5

Current limits: neutralino/chargino canonical case degenerate case trilepton+met from χ ± χ 5 4 tan$= ADLO #= GeV!s! 6.5 GeV 7 8 9 ADLO preliminary Gaugino M# ~! 5 GeV expected limit 3 M# + (GeV "M (GeV 99 Excluded at 95" C.L. 4 6 8 M" ~ (GeV 7 8 9 M! ~ + (GeV mχ ± > 38 GeV (msugra tanβ=3, A= mχ ± > 3.5 GeV for msnue > 3 GeV LEPSUSYWG/3. mχ ± > 9.9 /9.4 GeV LEPSUSYWG/4. CDF Note 636 D: arxiv:9.646 mχ > 47/5 GeV (CMSSM, msugra No mass limit in general S. Su 6

Current limits: neutralino/chargino canonical case degenerate case trilepton+met from χ ± χ 5 4 tan$= ADLO #= GeV!s! 6.5 GeV 7 8 9 ADLO preliminary Gaugino M# ~! 5 GeV expected limit 3 M# + (GeV "M (GeV 99 Excluded at 95" C.L. 4 6 8 M" ~ (GeV 7 8 9 M! ~ + (GeV mχ ± > 38 67 GeV (msugra tanβ=3, A= mχ ± > 3.5 GeV for msnue > 3 GeV LEPSUSYWG/3. mχ ± > 9.9 /9.4 GeV LEPSUSYWG/4. CDF Note 636 D: arxiv:9.646 mχ > 47/5 GeV (CMSSM, msugra No mass limit in general S. Su 6

Current limits: neutralino/chargino canonical case degenerate case trilepton+met from χ ± χ 5 4 tan$= ADLO #= GeV!s! 6.5 GeV 7 8 9 ADLO preliminary Gaugino M# ~! 5 GeV expected limit M# + (GeV 3 99 Excluded at 95" C.L. 4 6 8 M" ~ (GeV... mχ ± > 3.5 GeV for msnue > 3 GeV LEPSUSYWG/3. Have at least one of these assumptions: gaugino mass unification: M= (5/3 tan θw M = / M "M (GeV sfermion mass unification decouple sfermions mχ ± > 9.9 /9.4 GeV LEPSUSYWG/4. S. Su 6 msugra 7 8 9 M! ~ + (GeV particular benchmark point mχ ± > 38 67 GeV (msugra tanβ=3, A= CDF Note 636 D: arxiv:9.646 mχ > 47/5 GeV (CMSSM, msugra No mass limit in general

Limits from LHC with fb "! A [pb] 95% CL UL 8 7 6 5 4 3 3 OSL! CLs observed limit 5 5 5 3 m cut Expected ± " CMS preliminary s = 7 TeV,.98 fb Expected ± " LM [GeV] [GeV] m! " SSL MET> GeV, no jet requirement 35 3 5 5 5! " ±! " m"! & ~ ~ ~ % l# ll, l# " ll % l#! " ± = m ", m ~! l,# " L dt =.4 fb Observed 95% CL Expected Expected ± $ ATLAS ll! " = m LSP + / (m " m " ±, s=7 TeV 5 5 3 35 ± [GeV]!! m "!, "! 5 4 3. Cross Section Excluded at 95% CL [pb] ATLAS.689 CMS PAS SUS S. Su 7

Current limits: slepton @ LEP mse > 99.6 GeV, msmu > 94.9 GeV, mstau > 85.9 (85. GeV LEPSUSYWG/4. M! (GeV/c 8 6 #s = 838 GeV ADLO + ẽ RẽR + " R" + " R" R R M l! M! R for slr, conservative = GeV, tanβ=.5 gaugino mass unification affect selectron production and decay 4 Observed Expected Excluded at 95# CL ("= GeV/c, tan$=.5 5 6 7 8 9 M l (GeV/c selser production via tchannel mser > 73 GeV independent of mχ (msermχ ± small msnue > 45 GeV (z width indirect limit from slepton search S. Su 8 R

MSSM Electroweak sector Gauginos and Higgsinos ~ ~ Neutral ones: Bino, Wino, Hu, Hd ~ charged ones: Winos, Hu + ~, Hd Neutralinos and charginos Parameters: M, M,, tanβ Sleptons: sll, slr, three generations No flavor mixing No LR mixing for the st, nd generations sel, ser, smul, smur, stau, stau Parameters: MslL, MslR, (LR for stau? universality? S. Su 9

Neutralinos Neutralinos MÑ = ψ =( B, W, H d, H u M c β s W m Z s β s W m Z M c β c W m Z s β c W m Z c β s W m Z c β c W m Z s β s W m Z s β c W m Z, M M Bino Wino Higgsino Higgsino χ χ χ 3 χ 4 = O M O O m Z M M M O M O O m Z M M M O O M O M M O M B W H d H u S. Su

Charginos Charginos ψ ± =( W +, H + u, W, H d sβ m W M C = X T X, with X = M cβ m W M Wino Higgsino χ + χ + = O O M M W + H + u χ χ = O O M M W H d S. Su

Order of M, M and Bino LSP M < M, Wino LSP M < M, Higgsino LSP < M, M Bino Wino Higgsino e.g.: sugra, CMSSM, gaugino mass unification,... canonical case e.g.: AMSB,... Chen et. al., hepph/953 Moroi et. al., hepph/9945 Gherghetta et. al., hepph/994378 Bear et. al., hepph/773 Moroi et. al., ArXiv: 8.375 e.g.: Higgsinoworld,... Baer, Barger and Huang, ArXiv: 7.558 S. Su

Bino LSP case light wino M < M < light Higgsino M < < M Higgsino Wino Wino Higgsino Bino χ χ ± χ χ ± Bino S. Su 3

Masses light wino M < M < light Higgsino M < < M 5 5 45 45 m! (GeV 4 35 3 5 5!,! "! m! (GeV 4 35 3 5 5! 3!,! "! 5 3 4 5 M (GeV 5 3 4 5! (GeV S. Su 4

Neutralino and Chargino mixing Neutralinos Charginos light wino χ B +O( m Z M W χ +O H d +O H u O M B + W +O H d +O H u χ + W + +O H + u χ W +O H d light Higgsino χ B +O( m Z M W +O H d +O H u χ χ 3 O B +O M W + H d H u O B +O M W + H d + H u χ + χ O M W + O M W + H + u + H d S. Su 5

Productions: Wino NLSP case light wino M < M <! (pb tan" =,! = TeV M = GeV, LO M = GeV, NLO M = 3 GeV, LO M = 3 GeV, NLO! (pb 3 tan# =, " = TeV, M = GeV χ ± χ χ + χ " " " " " " " " " " " " " " " " " "! +!! 3 3 3 3 3 4 5 3 6 3 4 5 6 7 M (GeV 3 4 5 6 7 M (GeV cross section has little dependence on M S. Su 6

Productions: Wino NLSP case! (pb 3 light wino M < M < χ χ χ ± χ light Wino light Higgsino M < <M light Higgsino M < < M M tan" =,! = TeV χ ± χ χ χ χ ± χ χ χ M = GeV, LO M = GeV, NLO M = 3 GeV, LO M = 3 GeV, NLO M χ ± χ 3 χ χ 3 χ χ 3 3 4 5 6 7 χ 3 χ 3 M M (GeV cross section has little dependence on M 3 4 5 6 7 M (GeV S. Su 6! (pb 3 4 5 6 tan# =, " = TeV, M = GeV χ ± χ χ + χ " " " " " " " " " " " " " " " " " "! +!! 3 3 3 3 3

Neutralino/Chargino decays when slepton decouple χ ± χ W ± light Wino light Higgsino M < <M M χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M S. Su 7

Neutralino/Chargino decays when slepton decouple light Wino light Higgsino M < <M χ ± χ W ± M χ ± l ν l, lν l M χ ± decay % via on/offshell W when no light slepton χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M S. Su 7

Neutralino/Chargino decays when slepton decouple light Wino light Higgsino M < <M χ ± χ W ± M χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M χ ± decay % via on/offshell W when no light slepton χ onshell decay to h dominate over onshell Z χ l l R M S. Su 7

χ ± decay with decoupled slepton light wino M < M <!" "!! " (? # #!" "!! " '(!! " (@@ $ χ!! " (9# 9./((!"!!!! " ("# " 34''.5!"!!!! " ',,!! " '!! " '**!! " '##!! " '""!"!# χ ±!"" #"" $"" %"" &"" ' # ((*+,!"!#! "! "! '$! '++!"" #"" $"" %"" &"" # ''./ S. Su 8

χ ± decay with decoupled slepton light wino M < M <!" "!! " (? # #!" "!! " '(!! " (@@ $ χ!! " (9# 9./((!"!!!! " ("# " 34''.5!"!!!! " ',,!! " '!! " '** offshell W*!! " '##!! " '""!"!# χ ±!"" #"" $"" %"" &"" ' # ((*+,!"!#! "! "! '$! '++!"" #"" $"" %"" &"" # ''./ S. Su 8

χ ± decay with decoupled slepton light wino M < M <!" "!! " (? # #!" "!! " '(!! " (@@ $ χ!! " (9# 9./((!"!!!! " ("# " 34''.5!"!!!! " ',,!! " '!! " '** offshell W* onshell W!! " '##!! " '""!"!# χ ±!"" #"" $"" %"" &"" ' # ((*+,!"!#! "! "! '$! '++!"" #"" $"" %"" &"" # ''./ S. Su 8

χ ± decay with decoupled slepton!" " light wino M < M <!! " (?!! " (@@ $ onshell h!" " # #! "! '( χ!! " (9# 9./((!"!!!! " ("# " 34''.5!"!!!! " ',,!! " '!! " '** offshell W* onshell W!! " '##!! " '""!"!# χ ±!"" #"" $"" %"" &"" ' # ((*+,!"!#! "! "! '$! '++!"" #"" $"" %"" &"" # ''./ offshell Z* onshell Z S. Su 8

Neutralino/Chargino decays χ ± χ W ± light Wino light Higgsino M < <M M χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M S. Su 9

Neutralino/Chargino decays decay to onshell sll, snul dominant once it is open. χ ± χ W ± light Wino light Higgsino M < <M M χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M S. Su 9

Neutralino/Chargino decays decay to onshell sll, snul dominant once it is open. χ ± χ W ± light Wino light Higgsino M < <M M χ ± l ν l, lν l M offshell sll/snul dominate over offshell Z/W χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M S. Su 9

Neutralino/Chargino decays decay to onshell sll, snul dominant light Wino light Higgsino M < <M onshell/offshell decay via Z/W once it is open. χ ± χ W ± M dominate over slepton χ ± l ν l, lν l M offshell sll/snul dominate over offshell Z/W χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M S. Su 9

Neutralino/Chargino decays decay to onshell sll, snul dominant light Wino light Higgsino M < <M onshell/offshell decay via Z/W once it is open. χ ± χ W ± M dominate over slepton offshell sll/snul dominate over offshell Z/W χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M slepton important as the only onshell decay χ l l R M S. Su 9

χ ± decay: light leftslepton light wino M < M < light Higgsino M < < M!! & :*;<=( &,&""4*5>(!,?""4*5>.,&"""4* &" "!! & :*;<=( &,&""4*5>(!,&"""4*5>",?""4*5 &" "! & " @! & " AA "! & " B# B &"!& &"!&! & " $# $ /B# B 78396 78396 /.&# $ &"!! &"!! &"!' χ ±!"" #"" $"" %"" &"" (*+,(.+,(/.+34*56 &"!' χ ±!"" #"" $"" %"" &""" (*+,(.+,(/.+34*56 S. Su

χ ± decay: light leftslepton light wino M < M < light Higgsino M < < M!! & :*;<=( &,&""4*5>(!,?""4*5>.,&"""4* &" "!! & :*;<=( &,&""4*5>(!,&"""4*5>",?""4*5 &" "! & " @! & " AA "! & " B# B 78396 &"!& lepton rich final states 78396 &"!&! " & $# $ /B# B /.&# $ &"!! &"!! &"!' χ ±!"" #"" $"" %"" &"" (*+,(.+,(/.+34*56 &"!' χ ±!"" #"" $"" %"" &""" (*+,(.+,(/.+34*56 S. Su

χ ± decay: light leftslepton light wino M < M < light Higgsino M < < M!! & :*;<=( &,&""4*5>(!,?""4*5>.,&"""4* &" "!! & :*;<=( &,&""4*5>(!,&"""4*5>",?""4*5 &" "! & " @! & " AA "! & " B# B 78396 &"!& &"!! lepton rich final states change decay when sll onshell in Wino case 78396 &"!& &"!!! " & $# $ /B# B /.&# $ &"!' χ ±!"" #"" $"" %"" &"" (*+,(.+,(/.+34*56 &"!' χ ±!"" #"" $"" %"" &""" (*+,(.+,(/.+34*56 S. Su

χ ± decay: light leftslepton light wino M < M < light Higgsino M < < M!! & :*;<=( &,&""4*5>(!,?""4*5>.,&"""4* &" "!! & :*;<=( &,&""4*5>(!,&"""4*5>",?""4*5 &" "! & " @! & " AA "! & " B# B 78396 &"!& &"!! lepton rich final states change decay when sll onshell in Wino case 78396 &"!& &"!! sll does not affect much of Higgsino case! " & $# $ /B# B /.&# $ &"!' χ ±!"" #"" $"" %"" &"" (*+,(.+,(/.+34*56 &"!' χ ±!"" #"" $"" %"" &""" (*+,(.+,(/.+34*56 S. Su

χ,± decay: offshell effects of sll light wino M < M < 6785!! & 9:;<' & +&""34='!+&$"34=,+&"""3 &" " &"!& 5674! "! 89/:;'&+&""3<'!+&$"3<,+&"""3 &" " &"!& == >>?? "" ## (?? (./" (@? #? &"!! χ ±!"" #"" $"" %"" &"" '(*+'(,*+'./*345 &"!! χ!"" #"" $"" %"" &""" '(*+'(,*+'(./*34 S. Su

χ,± decay: offshell effects of sll light wino M < M < 6785!! & 9:;<' & +&""34='!+&$"34=,+&"""3 &" " &"!& onshell sl 5674! "! 89/:;'&+&""3<'!+&$"3<,+&"""3 &" " &"!& == >>?? "" ## (?? (./" (@? #? &"!! χ ±!"" #"" $"" %"" &"" '(*+'(,*+'./*345 &"!! χ!"" #"" $"" %"" &""" '(*+'(,*+'(./*34 S. Su

χ,± decay: offshell effects of sll light wino M < M < 6785!! & 9:;<' & +&""34='!+&$"34=,+&"""3 &" " &"!& onshell sl 5674! "! 89/:;'&+&""3<'!+&$"3<,+&"""3 &" " &"!& == >>?? "" ## (?? (./" (@? #? offshell sl* &"!! χ ±!"" #"" $"" %"" &"" '(*+'(,*+'./*345 &"!! χ!"" #"" $"" %"" &""" '(*+'(,*+'(./*34 S. Su

χ,± decay: offshell effects of sll light wino M < M < 6785!! & 9:;<' & +&""34='!+&$"34=,+&"""3 &" " &"!& onshell sl 5674! "! 89/:;'&+&""3<'!+&$"3<,+&"""3 &" " &"!& == >>?? "" ## (?? (./" (@? #? &"!! offshell sl* offshell W χ ±!"" #"" $"" %"" &"" '(*+'(,*+'./*345 &"!! χ!"" #"" $"" %"" &""" '(*+'(,*+'(./*34 S. Su

χ,± decay: offshell effects of sll light wino M < M < 6785!! & 9:;<' & +&""34='!+&$"34=,+&"""3 &" " &"!& 5674! "! 89/:;'&+&""3<'!+&$"3<,+&"""3 &" " &"!& == >>?? "" ## (?? (./" (@? #? offshell sll mediated decay is relevant till msel about 5 GeV. &"!! χ ±!"" #"" $"" %"" &"" '(*+'(,*+'./*345 &"!! χ!"" #"" $"" %"" &""" '(*+'(,*+'(./*34 S. Su

Neutralino/Chargino decays χ ± χ W ± light Wino light Higgsino M < <M M χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M S. Su

Neutralino/Chargino decays light Wino light Higgsino M < <M χ ± χ W ± M χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M χ l l R M χ ± :slr does not affect χ ± decay, except stau via LR mixing S. Su

Neutralino/Chargino decays light Wino light Higgsino M < <M χ ± χ W ± M χ ± l ν l, lν l M χ χ Z χ χ h χ l l L, ν l ν l, M χ ± :slr does not affect χ ± decay, except stau via LR mixing χ : slr important as the only onshell decay χ l l R M S. Su

LHC searches Collider signatures jets + MET l + jets + MET OSl + jets + MET SSl + jets + MET: include trilepton Validation of MonteCarlo: compare with CMS analyses for Luminosity up to fb LM, event field from CMS single lepton study: 8.7 ±. Our simulation: 8.77 Upper limit at 95% CL on event yield using existing CMS searches L observed BG 95%CL jets + MET. fb 8 channels......... l + jets + MET 36 pb 9 7 ± 7. 4 OSl + jets + MET.98 fb high MET 8 4. ±.3 high HT 4 5. ±.7 5.3 SSl + jets + MET.98 fb 7 channels......... S. Su 3

95% CL upper limit on cross sections SSl+jets + MET M (GeV 9 8 # " BR (pb SS / dileptons (MET >, H T tan! =, = TeV > 8 GeV 9 8 M (GeV 9 8 # " BR (pb SS / dileptons (MET > 5, H T tan! =, = TeV > 4 GeV 9 8 7 7 7 7 6 6 6 6 5 5 5 5 4 4 4 4 3 3 3 3 3 4 5 6 7 8 9 M (GeV 3 4 5 6 7 8 9 M (GeV low HT cut has better reach! probably best exclusion channel among four searches S. Su 4

95% CL upper limit on cross sections SSl+jets + MET M (GeV 9 8 7 # " BR (pb SS / dileptons (MET >, H T tan! =, = TeV > 8 GeV 9 8 7 M (GeV! (pb 9 8 7 # " BR (pb SS / dileptons (MET > 5, H T tan! =, = TeV tan" =,! = TeV > 4 GeV M = GeV, LO M = GeV, NLO M = 3 GeV, LO M = 3 GeV, NLO 9 8 7 6 6 6 6 5 5 5 5 4 4 4 4 3 3 3 3 3 3 4 5 6 7 8 9 M (GeV 3 3 4 546 7 5 8 6 9 7 M (GeV M (GeV low HT cut has better reach! probably best exclusion channel among four searches S. Su 4

95% CL upper limit on cross sections M (GeV SSl+jets + MET 9 8 7 6 5 4 3 # " BR (pb SS / dileptons (MET >, H T tan! =, = TeV > 8 GeV 3 4 5 6 7 8 94 M (GeV low HT cut has better reach! probably best exclusion channel among four searches M (GeV 9 8 7 6 5 3 9 8 7 M (GeV! (pb 9 8 7 " 6upper limit 6 fb # " BR (pb 3 need jet veto. SS / dileptons (MET > 5, H T tan! =, = TeV SS / dileptons (MET >, H > 8 GeV 5 5 T tan! =, = TeV 4 4 Nj 3 requirements 3 too strong. tan" =,! = TeV > 4 GeV M = GeV, LO M = GeV, NLO M = 3 GeV, LO M = 3 GeV, NLO 4 3 3 4 546 7 5 8 6 9 7 9 8 7 6 5 9 8 7 6 5 4 3 M (GeV M (GeV 3 3 4 5 6 7 8 9 S. Su M 4 (GeV

95% CL upper limit on cross sections M (GeV # " BR (pb 9 Single Lepton Analysis (MET > 5 GeV 9 8 tan! =, = TeV 8 7 7 l+jets + MET 6 6 5 5 4 4 3 3 $# Acceptance 9 " T : 75 < H T (GeV < 35 8 tan! =, = TeV 3 4 5 6 7 8 9 7 M (GeV 6 5 jets M + (GeV MET M (GeV 9 8 7 6 5 4 3 # " BR (pb OS dilepton Analysis (MET > 75, H T tan! =, = TeV OSl+jets + MET.35.3 > 3 GeV 3 4.5 5 6 7 8 9. M (GeV 5 45 4 35 3 5 5 5 4.5 3..5 S. Su 3 4 5 6 7 8 9 5 M (GeV

Reach in MM and Mmu plane with optimized cuts... M (GeV 9 8 7 $# Acceptance fb " T : H T (GeV > 875 tan! =, = TeV 5 fb M (GeV 9 8 7 $# Acceptance " T : H T (GeV > 875 tan! =, M = TeV 6 6 5 5 4 4 3 3 3 4 5 6 7 8 9 M (GeV 3 4 5 6 7 8 9 S. Su 6

Reach in MM and Mmu plane with optimized cuts... M (GeV 9 8 7 $# Acceptance fb " T : H T (GeV > 875 tan! =, = TeV 5 fb M (GeV 9 8 7 $# Acceptance " T : H T (GeV > 875 tan! =, M = TeV 6 6 5 4 3 5 Results will come 4 (very soon... 3 3 4 5 6 7 8 9 M (GeV 3 4 5 6 7 8 9 S. Su 6

Slepton studies DrellYan production cross section small % (pb 3!!!3!4 e ~ ~ R e R e ~ ~ L e L = solid $ ~ ~ L $ L = dotdash W ± # ~ e ~ L $ L "s = 4 TeV 3 4 5 ~ (GeV m l SM BG large: W, WW, WZ, ttbar, etc. usually done in msugra framework Limited reach: L=3 fb, GeV for slr, 3 GeV for sll Y.M.Andreev, S.I.Bityukov, N.V.Krasnikov, hepph/49; H.Baer, C.h.Chen, F.Paige, X.Tata,hepph/ 9348, hepph/95383 S. Su 7

Slepton decay direct decay: sll, slr l χ snul ν χ MET, l+met, l+met signal cascade decay: light wino case, MseL > M sll, slr l χ, ν χ ± snul ν χ, l χ ± complicated signature *+,4*5678,(&9&"",.*/:,(!9;"",.*/:,<=9&""",.* &" ", *+,4*5678,(&9&"",.*/:,(!9&""",.*/:,;<9="",.*/ &" ",! & ",*!! ",*! ' ",* &"!& &"!&! &!," *,,3,,3 &"!! &"!! &"!', light wino light Higgsino, S.!"" Su #"" $"" %"" &"" 8 (*+,,.*/ &"!'!"" #"" $"" %"" &""" (*+,,.*/

Slepton decay direct decay: sll, slr l χ snul ν χ MET, l+met, l+met signal cascade decay: light wino case, MseL > M sll, slr l χ, ν χ ± snul ν χ, l χ ± complicated signature *+,4*5678,(&9&"",.*/:,(!9;"",.*/:,<=9&""",.* &" ", *+,4*5678,(&9&"",.*/:,(!9&""",.*/:,;<9="",.*/ &" ",! & ",*!! ",*! ' ",*,,3 &"!& &"!! &"!', light wino ll lχ &"!! ll lχ m Z M S. Su &"!',!"" #"" $"" %"" &"" 8 (*+,,.*/ ll νχ ±,,3 &"!& light Wino light Higgsino M < <M m Z M light Higgsino!"" #"" $"" %"" &""" (*+,,.*/! &!," *

Slepton from Neutralino/Chargino decay For MseL < M, light Wino case larger cross sections!"! 4 TeV l l +!*+*"*#!! *## " /***+/!" "!"!! χ χ + l + l ν ν χ χ!"!#!"" #"" $"" %"" &"" '"" ("" # **+,./ S. Su 9

Slepton from Neutralino/Chargino decay large branching ratios 35 M=5 GeV, M=4 GeV trilepton + MET signal, less SM BG Events/.5 GeV/ fb 4 3 5.7 / 97 P 9. P 8.7 P3.9 5 5 M ll (GeV Text 5 5 5 3 35 4 m slepton (GeV distinctive triangle shape for mll obvioustoeye spectral shape How to use it to enhance our signal significance? enhanced by only plotting the signal How about BG? : l + Bachacou, l mass S. Su distribution Hinchliffe, showing and Paige, the χhepph/99758 MINUIT fit using PAW. 3 m cutoff (GeV 3 5 5 5 m (m cutoff = m m χ χ m m χ mz

Do We See the triangle? Events / 3 GeV 4 8 6 4 5 5 5 3 35 4 45 m e + e S. Su 3

Do We See the triangle? Events / 3 GeV 4 8 6 4 Events / 3 GeV 3 5 5 5 3 35 4 45 m e + e 5 5 5 3 35 4 45 (GeV S. Su 3 m e + e

Do We See the triangle? Events / 3 GeV 4 8 6 4 Events / 3 GeV 3 m_ee 5 5 5 3 35 4 45 Events / 3 GeV m e + e 4 8 6 4 5 5 5 3 35 4 45 (GeV S. Su 3 m e + e 4 6 8 4 6 8 m ee

Signal and background Signature: trilepton + MET Signal: MSSM χ ± χ production, for a given (M, M, MseL mcut Dominant SM backgrounds: WZ (anything containing Z ttbar+fake (from b, measurable from data, data driven method to understand the BG better Dominant SUSY backgrounds: χ ± χ WZχ χ, containing a Z would be included Br into W/Z small if dominantly decay into sleptons S. Su 3

Fitting Events / 3 GeV 4 Events / 3 GeV 3 4 TeV fb 8 6 4 4 6 8 4 6 (GeV m e + e 5 5 5 3 35 4 45 (GeV m e + e Z peak amplitude peak position width ttbar+fake fake rate Signal triangle signal counts mll cutoff gaussian smearing S. Su 33

Cross section reach given mcut, marginalizing over other fitting parameters Nsig required for 5 sigma required sigma*br*acc l l + 4 TeV fb X Y Z X Y Z l + ν Model independent result! Can be applied to other model with similar topology background fitting: any process give a Z peak results only sensitive to mcut given model mx, my, mz mcut sigma*br*acc S. Su 34

MSSM Slepton: 4 TeV Reach Apply to MSSM case, slepton from χ ± χ decay selectron only mse=msmu=mstau, e/mu final states Luminosity [fb ] Luminosity [fb ] Slepton Mass [GeV] 6 5 4 3 Slepton Mass [GeV] 6 5 4 3 3 3 3 4 5 6 7 Wino Mass [GeV] 3 4 5 6 7 Wino Mass [GeV] L= fb, reach sll up to 6 GeV L= fb, reach sll up to 5 GeV S. Su 35

Conclusions LHC has great reach for colored particles, but more studies needed to explore LHC potential for EW particles. Current LHC search already set strong bounds (TeV on the mass of colored object, however, the search strategy is not optimized for EW particles. Existing study on EW particles make simple assumptions, e.g., msugra or gaugino mass unification relation MSSM EW sector: neutralinos, charginos and sleptons with general parametrization S. Su 36

Conclusions Neutralinos/charginos: light wino and light Higgsino cases decay pattern depends on the slepton masses LHC reach of neutralinos/charginos with decoupled slepton MM, M light slepton: slepton via neutralino/chargino decay utilize the triangle shape in mll distribution model independent approach: results can be applied to other models, and various mass spectrum MSSM: 4 TeV with fb, MseL up to 6 GeV S. Su 37

Regions to be explored neutralino/chargino reach for slepton heavier than χ /χ ±, but accessible through offshell slepton decay lepton rich final state, but no triangle feature slepton DY, direct decay, for nonsugra spectrum slepton DY with cascade decay... S. Su 38