Supersymmetry at the LHC

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1 Supersymmetry at the LHC Howard Baer Florida State University SUSY at LHC SUSY models GEANT figure sparticle production msugra : ~ g - W + b ( jet4, s ( jet5, ~+ ( jet3, W2 + b ~+ W1 + Z ~ Z1 + event generation precision measurements tan β = 35, µ > 0 ~ ul ~ t1 t sparticle decay searches at LHC m 0 = 1000 GeV, m 1/2 = 500 GeV, A 0 = 0, ~ Z 2 + u ( jet6, E T = 1196 GeV) ~ Z1 + h E = 113 GeV) T b ( jet1, E = 206 GeV) E = 79 GeV) + -c - ( jet2, E T = 320 GeV) T b T E = 536 GeV) T νν + + miss W τ ν + E T = 380 GeV e ν ~ Z1 b-jet 2 b-jet 1 m ~g = 1266 GeV m ~u = 1450 GeV b-jet 3 L m ~t = 1026 GeV 1 m ~Z = 410 GeV 2 m ~ = 214 GeV Z jet 6 1 m h = 119 GeV b-jet 4 S. Abdullin, A. Nikitenko jet 5 ~ Z1 S. Abdullin Oct H. Baer, SUSY at LHC, August 11,

2 Models of SUSY breaking Spontaneous breaking of SUSY phen. inconsistent within MSSM Hidden sector models (HS) HS is arena for SUSY breaking; how to communicate SUSY breaking to visible sector (VS)? gravity mediation: supergravity (SUGRA) and local SUSY: minimal messenger sector: m 3/2 TeV: LSP=bino/higgsino/wino/gravitino? gauge mediation (GMSB): introduce messenger sector fields as intermediary between HS and VS: m 3/2 TeV: LSP=gravitino anomaly mediation (AMSB): m 3/2 > TeV: LSP=wino role of extra dimensions? compactification? sequestered sector and AMSB; gaugino mediation; GUTs; H. Baer, SUSY at LHC, August 11,

3 Calculate spectra using Isajet/Isasugra MSSM: weak scale inputs (no RGE running) msugra m 0, m 1/2, A 0, tan β, sign(µ) non-universal SUGRA gauge mediated SUSY breaking (GMSB) Λ, M, n 5, tan β, sign(µ), C grav non-minimal GMSB anomaly-mediated SUSY breaking (AMSB) m 0, m 3/2, tanβ, sign(µ) non-minimal AMSB mixed modulus-amsb α, m 3/2, tan β, sign(µ), modular weights H. Baer, SUSY at LHC, August 11,

4 Sparticle mass spectra Mass spectra codes RGE running: M GUT M weak Isajet (HB, Paige, Protopopescu, Tata) 7.72: Isatools SuSpect (Djouadi, Kneur, Moultaka) SoftSUSY (Allanach) Spheno (Porod) Comparison (Belanger, Kraml, Pukhov) Website: H. Baer, SUSY at LHC, August 11,

5 LEP2: Constraints on SUSY models m h > GeV for SM-like h m f W 1 > GeV mẽl,r > 99 GeV for m l m e Z 1 > 10 GeV BF(b sγ) = (3.25 ± 0.54) 10 4 (BELLE, CLEO, ALEPH) SM theory: BF(b sγ) a µ = (g 2) µ /2 (Muon g 2 collaboration) a µ = (27.1 ± 9.4) (Davier et al. e + e ) a SUSY µ m2 µ µm i tan β M 4 SUSY BF(B s µ + µ ) < constrains at very large tanβ > 50 Ω CDM h 2 = ± (WMAP) (CDF-new!) H. Baer, SUSY at LHC, August 11,

6 Results of χ 2 fit using τ data for a µ : m 1/2 (GeV) not LSP Ζ ~ 1 msugra with tanβ = 10, A 0 = 0, µ > No REWSB m 0 (GeV) m h =114.1GeV LEP2 excluded GENIUS CDMSII CDMS ln(χ 2 /DOF) m 1/2 (GeV) not LSP Ζ ~ 1 msugra with tanβ = 54, A 0 = 0, µ > No REWSB m 0 (GeV) m h =114.1GeV LEP2 excluded GENIUS CDMSII CDMS ln(χ 2 /DOF) HB, C. Balazs: JCAP 0305, 006 (2003) H. Baer, SUSY at LHC, August 11,

7 For a hadronic reaction, Parton model of hadronic reactions A + B c + d + X, where c and d are superpartners and X represents assorted hadronic debris, we have an associated subprocess reaction a + b c + d, whose cross section can be computed using the Lagrangian for the MSSM. To obtain the final cross section, we must convolute the appropriate subprocess production cross section dˆσ with the parton distribution functions: dσ(ab cdx) = a,b dx a dx b f a/a (x a, Q 2 ) f b/b (x b, Q 2 ) dˆσ(ab cd). 0 where the sum extends over all initial partons a, b whose collisions produce the final state c + d. (1) H. Baer, SUSY at LHC, August 11,

8 Chargino-neutralino production H. Baer, SUSY at LHC, August 11,

9 Chargino pair production H. Baer, SUSY at LHC, August 11,

10 Neutralino pair production H. Baer, SUSY at LHC, August 11,

11 Slepton pair production H. Baer, SUSY at LHC, August 11,

12 Slepton pair cross section H. Baer, SUSY at LHC, August 11,

13 Gluino pair production H. Baer, SUSY at LHC, August 11,

14 Squark pair production H. Baer, SUSY at LHC, August 11,

15 Gluino-squark associated production H. Baer, SUSY at LHC, August 11,

16 Gluino and squark pair production H. Baer, SUSY at LHC, August 11,

17 Production at Tevatron H. Baer, SUSY at LHC, August 11,

18 Production at LHC H. Baer, SUSY at LHC, August 11,

19 Gluino decays: g q q or 3-body H. Baer, SUSY at LHC, August 11,

20 Gluino decays: branching fractions H. Baer, SUSY at LHC, August 11,

21 Squark decays ũ L u Z i, d W + j, u g, d L d Z i, u W j, d g, ũ R u Z i, u g, d R d Z i, d g. H. Baer, SUSY at LHC, August 11,

22 Slepton decays ẽ L e Z i, ν e W j, ν e ν e Zi, e W + j, ẽ R e Z i. H. Baer, SUSY at LHC, August 11,

23 Chargino decays W j W Z i, H Zi, ũ L d, dl u, c L s, s L c, t 1,2 b, b1,2 t, ν e ē, ẽ L ν e, ν µ µ, µ L ν µ, ν τ τ, τ 1,2 ν τ, and W 2 Z W 1, h W 1, H W 1 and A W 1. Charginos may decay to a lighter neutralino via W j Z i + f f, (2) H. Baer, SUSY at LHC, August 11,

24 Neutralino decays Z i W W j, H W j, Z Z i, h Z i, H Z i, A Z i q L,R q, q L,R q, ll,r l, ll,r l, ν l ν l, ν l ν l. If 2-body modes are closed,then the neutralino can decay via Z i Z i + f f (3) H. Baer, SUSY at LHC, August 11,

25 Sparticle cascade decays Mass scale (GeV) g ~ (2060) q ~ L ( 1857) q ~ R ( 1770) b ~ 2 (1690) t ~ 2 (1689) b ~ 1 (1619) 1400 t ~ 1 (1449) W ~ ± 2 (1067) Z ~ 4 (1066) Z ~ 3 (1056) W ~ ± 1 (754) Z ~ 2 (754) τ ~ 2 (726) ν ~ τ (712) 400 τ ~ 1 (442) Z ~ 1 (395) Br (%) Z ~ 1 qq (27.0 %) Z ~ 1 τνwbb (12.1 %) Z ~ 1 ττwwbb (8.4 %) Z ~ 1 WWbb (7.4 %) Z ~ 1 τνqq (5.9 %) Z ~ 1 τνwwwbb (4.1 %) Z ~ 1 ττbb (2.9 %) Z ~ 1 ττqq (2.9 %) Z ~ 1 τνzwbb (2.8 %) Z ~ 1 τνhwbb (2.6 %) H. Baer, SUSY at LHC, August 11,

26 Event generation for sparticles p 2 ~ g 3 ~ Z 1 1 ~ q Hadrons 4 ~ Z 1 p Remnants 5 Event generation in LL - QCD 1) Hard scattering / convolution with PDFs 2) Intial / final state showers 3) Cascade decays 4) Hadronization 5) Beam remnants H. Baer, SUSY at LHC, August 11,

27 Event generations for SUSY Isajet (HB, Paige, Protopopsecu, Tata) IH, FW-PS, n-cut Pomeron UE Pythia (Sjöstrand, Lönnblad, Mrenna) SH, FW-PS, multiple scatter UE, SUSY at low tanβ only Herwig (Marchesini, Webber, Seymour, Richardson,...) CH, AO-PS, Phen. model UE, Isawig H. Baer, SUSY at LHC, August 11,

28 SUSY scattering event: Isajet simulation SUSY event with 3 lepton + 2 Jets signature m 0 = 100 GeV, m 1/2 = 300 GeV, tanβ = 2, A 0 = 0, µ < 0, m(q) ~ = 686 GeV, m(g) ~ = 766 GeV, m(χ~ 0 2) = 257 GeV, m(χ~ 0 1 ) = 128 GeV. Jet2 Jet1 e - ~ χ 0 1 ~ χ 0 1 µ + µ - Leptons: p t (µ + ) = 55.2 GeV p t (µ - ) = 44.3 GeV p t (e - ) = 43.9 GeV Jets: E t (Jet1) = 237 GeV E t (Jet2) = 339 GeV Sparticles: ~ p t (χ 0 1 ) = 95.1 GeV p t (χ~ 0 1) = 190 GeV Charged particles with p t > 2 GeV, η < 3 are shown; neutrons are not shown; no pile up events superimposed. H. Baer, SUSY at LHC, August 11,

29 Search for SUSY at CERN LHC g g, g q, q q production dominant for m < 1 TeV lengthy cascade decays are likely E T + jets 1l+ E T + jets OS 2l+ E T + jets SS2l+ E T + jets 3l+ E T + jets 4l+ E T + jets BG: W + jets, Z + jets, t t, b b, WW, 4t, Grid of cuts gives optimized S/B H. Baer, SUSY at LHC, August 11,

30 Pre-cuts and cuts E T > 200 GeV N j 2 (where p T (jet) > 40 GeV and η(jet) < 3 Grid of cuts for optimized S/B: N j 2 10 E T > GeV E T (j1) > GeV E T (j2) > GeV S T > muon isolation S > 10 events for 100 fb 1 S > 5 B for optimal set of cuts H. Baer, SUSY at LHC, August 11,

31 Sparticle reach of LHC for fb m 1/2 (GeV) msugra with tanβ = 10, A 0 = 0, µ > 0 Z l + l - 2l OS 1l 4l γ 0l 2l SS 3l m(u ~ L )=2 TeV m(g ~ )=2 TeV E T miss m 0 (GeV) m 1/2 (GeV) msugra with tanβ = 30, A 0 = 0, µ > 0 3l 2l OS Z l + l - 1l 4l γ 0l 2l SS m(u ~ L )=2 TeV m(g ~ )=2 TeV E T miss m 0 (GeV) HB, Balazs, Belyaev, Krupovnickas, Tata: JHEP 0306, 054 (2003) H. Baer, SUSY at LHC, August 11,

32 Sparticle reach of all colliders and relic density 1600 msugra with tanβ = 10, A 0 = 0, µ > 0 Ωh 2 < LEP2 excluded 1600 msugra with tanβ = 45, A 0 = 0, µ < 0 Ωh 2 < LEP2 excluded m 1/2 (GeV) LHC m 1/2 (GeV) LHC 600 LC LC LC LC Tevatron 200 Tevatron m 0 (GeV) m 0 (GeV) HB, Belyaev, Krupovnickas, Tata: JHEP 0402, 007 (2004) H. Baer, SUSY at LHC, August 11,

33 Precision measurements at LHC M eff = E T + E T (j1) + + E T (j4) sets overall m g, m q scale m(l l) < m ez2 m ez1 mass edge m(l l) distribution shape combine m(l l) with jets to gain m(l lj) mass edge: info on m q further mass edges possible e.g. m(l ljj) Higgs mass bump h b b likely visible in E T + jets events in favorable cases, may overconstrain system for a given model methodology very p-space dependent some regions are very difficult e.g. HB/FP H. Baer, SUSY at LHC, August 11,

34 M eff = E T (j1) + E T (j2) + E T (j3) + E T (j4)+ E T dσ/dm eff (mb/400 GeV) M eff (GeV) Atlas TDR (F. Paige) H. Baer, SUSY at LHC, August 11,

35 m(l + l ) mass edge from Z 2 l + l Z1 400 signal SM backg SUSY backg events/4 GeV/30 fb m ll (GeV) Atlas TDR (F. Paige) H. Baer, SUSY at LHC, August 11,

36 m(l + l q) mass edge from q q Z Events/20 GeV/100 fb m llq (GeV) Atlas TDR (F. Paige) H. Baer, SUSY at LHC, August 11,

37 m(b b) Higgs mass bump in SUSY jets + E T events signal SM backg SUSY backg Events/8 GeV m bb (GeV) Atlas TDR (F. Paige) H. Baer, SUSY at LHC, August 11,

38 Conclusions SUSY models SUGRA models most naturally encompass DM: thermal WIMPS WMAP bound Ω e Z 1 h 2 = ± especially constraining bulk, τ coann., HB/FP, A-funnel, h-funnel, t 1 coann. Various regions distinct collider/dm signatures SUSY (SUGRA) at LHC sparticle production sparticle decays event generation studies of when S > 5 B for given int. lum. a variety of precision measurements likely possible if SUSY discovered at LHC H. Baer, SUSY at LHC, August 11,

Supersymmetry at the LHC

Supersymmetry at the LHC Howard Baer Florida State University SUSY at LHC SUSY signatures SM backgrounds GEANT figure msugra : ~ g m 0 = 1000 GeV, m 1/2 = 500 GeV, A 0 = 0, ~ ul ~ t1 t - W + b ( jet4,