SUSY and Exotica. Talk outline. Ben Allanach (University of Cambridge)

Transcription

1 SUSY and Exotica by Ben Allanach (University of Cambridge) Talk outline SUSY Fits Impact of LHC data SUSY Tactics Exotica and A FB (t t) Please ask questions while I m talking SUSY and Exotica B.C. Allanach p. 1

2 A Problem With the Higgs Boson The Higgs boson mass receives quantum corrections from heavy particles in the theory: F h λ λ h aλ2 d n k 16π F 2 k 2 m F Quantum correction to Higgs mass: m phys h = 126 GeV/c 2 = m tree h +O(m F /100). m F GeV/c 2 is heaviest mass scale present. SUSY and Exotica B.C. Allanach p. 2

3 Electroweak Breaking Both Higgs get vacuum expectation values: ( ) ( ) ( ) ( H 0 1 v1 H H2 0 H 1 v 2 ) and to get M W correct, match with v SM = 246 GeV: β v SM v 2 tanβ = v 2 v 1 v 1 L = h t t L H 0 2 t R +h b bl H 0 1 b R +h τ τ L H 0 1 τ R m t sinβ = h tv SM 2, m b,τ cosβ = h b,τv SM 2. SUSY and Exotica B.C. Allanach p. 3

4 Supersymmetric Copies H SUSY and Exotica B.C. Allanach p. 4

5 Supersymmetric Copies H 2 H 2 SUSY and Exotica B.C. Allanach p. 4

6 Implementation We use 95% C.L. direct search constraints Ω DM h 2 = ±0.02 micromegas δ(g 2) µ /2 = (29.5±8.8) Stöckinger et al B physics observables including SusyBSG BR[b sγ] Eγ >1.6 GeV = (3.52±0.38) 10 4, BR(B s µµ) < micromegas Electroweak data W Hollik, A Weber et al 2lnL = i χ 2 i +c = i (p i e i ) 2 σ 2 i +c SUSY and Exotica B.C. Allanach p. 5

7 Additional observables δ (g 2) µ ( 100 GeV M SUSY ) 2 tanβ χ ± i γ µ γ µ ν µ χ 0 1 µ µ BR[b sγ] tanβ(m W /M SUSY ) 2 χ ± i γ H ± γ b t i s b t s SUSY and Exotica B.C. Allanach p. 6

8 ATLAS Weighted Fits 0.4 Allanach, Khoo, Lester and Williams Mar, Allanach, Khoo, Lester and Williams Mar, m 0 (TeV) m 0 (TeV) m 1/2 (TeV) m 1/2 (TeV) 0 Again, we assume A 0 -tanβ independence and interpolate across m 0 and m 1/2. CMS 35 pb 1, ATLAS 35 pb 1, CMS 1 fb 1 SUSY and Exotica B.C. Allanach p. 7

9 CMS/ATLAS Weighted Fits Allanach, Khoo, Lester and Williams, Mar 2011 Incl. ATLAS Excl. CMS/ATLAS Incl. CMS Allanach, Khoo, Lester and Williams, Mar 2011 Incl. ATLAS Excl. ATLAS Incl. CMS m ql /GeV m g /GeV Allanach, Khoo, Lester and Williams, Mar 2011 Incl. ATLAS Excl. ATLAS Incl. CMS Allanach, Khoo, Lester and Williams, Mar 2011 Incl. ATLAS Excl. ATLAS Incl. CMS m χ1 0/GeV m er /GeV SUSY and Exotica B.C. Allanach p. 8

10 Prospects for SUSY Still look good! 5fb 1 expected before christmas Allanach, Khoo, Lester and Williams, Mar 2011 Incl. ATLAS Excl. ATLAS Incl. CMS log 10 (σ SUSY /pb) SUSY and Exotica B.C. Allanach p. 9

11 pmssm Fits 25 pmssm input parameters are: M 1,2,3,A t,b,τ,µ,m H1,2,tanβ, m dr,l = m sr,l,mũr,l = m cr,l, mẽr,l = m µr,l,m t, b, τ R,L m t, m b (m b )α s (M Z ) MS,α 1 (M Z ) MS,M Z. Combined Bayesian fit a : Observable Measurement Fit(Log) m W [GeV] ± Γ Z [GeV] ± eff lep sin θ ± δ (g-2) ± µ 0 l R ± R ± b R ± c A ± e A ± b A ± c b FB A ± c FB A ± BR(B X s γ) ± O meas - O fit / σ meas R 1.11 ± BR(B τ ν) u R 1.15 ± M Bs ± CDM h Ω 0.11 ± a S.S. AbdusSalam, BCA, F. Quevedo, F. Feroz, M. Hobson, PRD81 (2010) , arxiv: SUSY and Exotica B.C. Allanach p. 10

12 Spectrum m h 2 4 m A m H m H ± µ[ 10 3 ] m χ m χ m χ 0 3 m χ 0 ± 4 m χ m χ ± m g Obtained with MultiNest a algorithm in 16 CPU years. Prior dependence is useful: which predictions are robust? a Feroz, Hobson arxiv: SUSY and Exotica B.C. Allanach p. 11

13 Collider SUSY Production Strong sparticle production and decay to dark matter particles. 7 TeV p q q q q p 7 TeV q,g q,g q Interaction ~ q q ~ q χ 0 1 χ 0 1 Any (light enough) dark matter candidate that couples to hadrons can be produced at the LHC SUSY and Exotica B.C. Allanach p. 12

14 α T,MET, M T2 Searches CMS: jets and missing energy arxiv: L = 35 pb 1. H T = N jet > 350 GeV. i=1 pj i T (1) H T j i A p j i T j i B p j i T. One then calculates (2) whereh/ T = α T = H T H T > HT 2 H/2 T ( N jet i=1 pj i x) 2 +( N jet i=1 pj i y) 2. SUSY and Exotica B.C. Allanach p. 13

15 CueM T2 m (i) T 2 (pt (i),/q T (i) ) 2 p T (i) /q T (i) (i) (i) 2p T /q T where /q (i) T is the missing transverse momentum from i. The variablem T2 is defined by: ( )} M T2 (p (1) T,p (2) T,/p T ) min /q T =/p T {max m (1) T,m(2) T The minimization is over all values of /q T (1,2) consistent with /q T = /p T. For the SUSY search, the unknown undetected particle masses are set to zero in M T2. SUSY and Exotica B.C. Allanach p. 14

16 M T2 Search 1 number of events/ 10GeV/ 100pb 3 10 SUSY signal (SPS1a) Z l l (l = e, µ, τ) Z νν W lν (l = e, µ, τ) tt QCD Figure 1: Only cuts: N j > 1, p T > 50 GeV, L = 100pb 1 at s = 7 TeV. Barr, Gwenlan PRD80 (2009) m T2 [GeV] SUSY and Exotica B.C. Allanach p. 15

17 M T2 v E miss T BCA, Barr, Dafinca, Gwenlan, JHEP 1107 (2011) 104, arxiv: SUSY and Exotica B.C. Allanach p. 16

18 Compressed Spectra SUSY and Exotica B.C. Allanach p. 17

19 Compressed Spectra II LeCompte, Martin, arxiv: SUSY and Exotica B.C. Allanach p. 18

20 Benchmarks Currently we a are devising SUSY benchmark models. It s imminent. CMSSM, NUHM, mamsb, mgmsb, RPV and some simplified models (via pmssm) are defined. Defining interesting parameter planes: identifying important parameters which control the masses of sparticles in each case. Discrete set of points along monotonic lines: next point for the experiments to study is defined as the lightest one that is not ruled out to 95% CL. a S.S. AbdusSalam, BCA H. Dreiner, J. Ellis, S. Heinemeyer, M. Krämer, M. Mangano, K.A. Olive, S. Rogerson, L. Roszkowski, SUSY and Exotica B.C. Allanach p. 19

21 A FB (t t) A FB = N(y t > y t) N(y t > y t ) N(y t > y t)+n(y t > y t ) A FB (CDF) lj+ll = (20.9±6.6)%, A FB (D0) lj = (19.6±6.5)%, SUSY and Exotica B.C. Allanach p. 20

22 CDF Seems to be increasing with mass. Lepton charge is nice verification. SUSY and Exotica B.C. Allanach p. 21

23 M t t SUSY and Exotica B.C. Allanach p. 22

24 A FB Exotica Must not disturb σ t t or dσ t t/dm t t axigluons a Z /W b SUSY and Exotica B.C. Allanach p. 23

25 LHC Asymmetry Defined LHC charge asym A C = N( y t > y t ) N(y t > y t ) N( y t > y t )+N(y t > y t ) SM discovery would take 60 fb 1 at 5σ, but new physics quicker (Z takes 2 fb 1 ) A CMS C = 1.6±3±1%A ATLAS C = 2.4±1.6±2.3% SUSY and Exotica B.C. Allanach p. 24

26 Models Z model is rather odd: only contains a vertex coupling utz, eg M Z = 800 GeV, g Z = 3.4: predicts significant same sign tops. W models also covered by LHC experiments by now. Heavy axigluon models eg 2 TeV, g q =-g t =2.4 are ruled out by LHC m jj searches Recent proposal a : axigluonsg = , M = GeV. They evade jet data because the have masses below current limits. Non-resonant production suppresses new physics contribution to σ t t. a SUSY and Exotica Krnjaic, arxiv: B.C. Allanach p. 25

27 Shopping List Things that the CMS/ATLAS always provide that we need: Cuts and numbers of events observed past them Expected background numbers with systematic errors We could really do with: Keeping in mind: we can t combine analyses that use the same events: much better to keep the events disjoint. Doesn t preclude fully inclusive analysis, but make the others as disjoint as possible. Likelihood versus predicted number of events past cuts (before efficiency correction). Ideally, SUSY and Exotica B.C. Allanach p. 26 sanitized RooStats

28 Shopping List II Failing that, then we must calculate the likelihood: Systematic errors on signals: perhaps at least a range over parameter space in one model. Ideally, it would be parameterised in terms of important quantities. Other contours (eg 1/5 sigma exclusion contours) so we can check our likelihood away from 95% excluded region. Numbers in histogram plots attached to arxiv publication SUSY and Exotica B.C. Allanach p. 27

29 Summary LHC analyses providing a nice amount of information for interpretation of data. There s always room for improvement... SUSY is late to the party, but not late enough to be reported missing CMSSM could well be discovered this/next year Current searches reach squark and gluino masses of 980 GeV. This will be extended to 1100 GeV next year, covering much of the good-fit region. t t asymmetry situation extremely murky. Many heavy axigluon models now ruled out. SUSY and Exotica B.C. Allanach p. 28

30 Supplementary Material SUSY and Exotica B.C. Allanach p. 29

31 CMS α T Search CMS: jets and missing energy arxiv: L = 35 pb 1. H T = N jet > 350 GeV. i=1 pj i T (3) H T j i A p j i T j i B p j i T. One then calculates (4) whereh/ T = α T = H T H T > HT 2 H/2 T ( N jet i=1 pj i x) 2 +( N jet i=1 pj i y) 2. SUSY and Exotica B.C. Allanach p. 30

32 Results SUSY and Exotica B.C. Allanach p. 31

33 ATLAS 0-lepton, jets and /p T m eff = p (j) T +p/ T, 2 (i) (pt,/q (i) T ) 2 (i) pt q / (i) (i) (i) 2pT T /q T m (i) T where /q (i) T is the transverse momentum of particle (i). For each event, it is a lower bound onm(nlsp). ( M T2 (p (1) T,p (2) T,/p T ) min /q T =/p T {max m (1) T,m(2) T )} SUSY and Exotica B.C. Allanach p. 32

34 Candidate Event: High E T (j) SUSY and Exotica B.C. Allanach p. 33

35 MSSM Exclusion: Simplified Model SUSY and Exotica B.C. Allanach p. 33