Composite gluino at the LHC

Transcription

1 Composite gluino at the LHC Thomas Grégoire University of Edinburgh work in progress with Ami Katz

2 What will we see at the LHC? Natural theory of EWSB? Supersymmetry? Higgs as PGSB (LH, RS-like)? Extra- Dimensions? Twin Higgs? Higgsless? Technicolor?

3 General Features New colored particles - Naturaleness Third generation of quark special? Stable particles? - MSSM: R-partiy ( 1) 3B+L+2S - Little Higgs : T-parity to avoid electroweak precision constraints. - R parity is more general: if conservation of Lepton and Baryon number.

4 Little Higgs - Models where the Higgs is a pseudo-goldstone boson. - Large spontaneously broken global symmetries. Explicit collective breaking : more than one couplings are required to give a mass to the Higgs. - Extended gauge, Yukawa and Higgs sectors. - same spin partner cancel quadratic divergences.

5 - Minimal Little Higgs Spectrum W cancel quadratic divergence of W φ cancel quadratic divergence of Higgs T cancel quadratic divergence of tops 1TeV - Goldstone bosons become strongly coupled at high energy. Needs a UV completion at 10TeV might have extra light states

6 Model: Strongly coupled UV completion of the littlest Higgs. Katz,Lee,Nelson, Walker 03 - Structure strongly coupled gauge theory Flavor symmetry 10TeV Littlest Higgs SU(5)/SO(5) SU(2) 2 U(1) Global symmetry Gauge symmetry 1TeV Standard Model

7 Spectrum above 10 TeV Ψ 11 { SU(5) global symmetry { { Composite top sector ψ 0 ψ 2 ψ 2 ψ3 c ψ 3 SU(3) c SU(2)

8 - Mesons ψ 2 ψ 0 ψ 2 Composites Σ Ψ 5 Ψ 5 = SU(5) broken to SO(5) - Baryons Ψ 11 Ψ 11 λ ψ 5 ψ 3 Ψ 11 { ψ 5 ψ 3 gaugino top top gluino

9 composite gaugino : ψ 5 ψ 5 λ ψ 3 ψ c 3λ C +, C, N g higgsino, bino, wino gluino R - partiy: ( 1) 3B+L+2S g C Ñ lighest of,, is stable dark matter? Masses are of the same order than the top partner because of flavor symmetry: 1TeV

10 Discovery of Little Higgs at LHC Z,W many new colored particles: large cross section Top partners couplings predicted by Little Higgs: Possible to measure but hard gluinos Perelstein, Pierce, Peskin 03 large cross section, missing energy signal

11 We have: missing energy, extra gauge bosons and extra fermions! can we tell what is going on? study the gluino

12 Composite gluino Decay of the composite gluino: 4-Fermi operators - Many operators. We concentrate on the following: gbt c C + f 2 g b t c C + g t c b C + gt c bc + f 2 gc + t c b f 2 g t c C + g C + b t c absent in supersymmetry b gc t c b f 2

13 Supersymmetric gluino Decay of a gluino in Supersymmetry q q e + e N 1 g q N 2 ẽ If most slepton and squark except the stop and sbottom are very heavy: t b W g t C N

14 If the stop and sbottom are off-shell: t g b C W N c b gbt c C + f 2 c t gt c bc + f 2 off shell sbottom off shell stop

15 There are no operators of the form c O1 gc + t c b f 2 c O2 gc + t c b f 2 - would require the exchange of a charged color octet. In supersymmetry we expect c b c t In composite model because of the flavor symmetry: c b c t

16 In both susy and non-susy: Gluino can be seen above background ~ -1 1fb De Sanctis, Laris, Montesano,Troncon 07 Gluino mass can be estimated from cross section Baer, Barger, Shaughnessy, at 10% with 100 ~ -1 1fb Summy Wang 07

17 Susy vs non-susy What observables can distinguish a supersymmetric gluino from the composite gluino? - with appropriate spectrum, the final states and kinematic of the decay are the same in both cases - We look at m 2 tb = (P t + P b ) 2 The distriubtion of m 2 tb is different. - m 2 tb is the only invariant distribution that can be measured.

18 m 2 tb distribution m g = 1TeV m C = 300GeV m N = 200GeV gbt c C + f 2 gc + t c b f 2 0 m 2 tb Susy vs non-susy

19 Problems: - Cuts deform shapes - Combinatoric Cuts: - More than 4 jets with - at least one hard jet - at least 2 b-tag jets. - missing E Measurement of m 2 tb. T > 300GeV P T > 40GeV P T > 150GeV Hisano,Kawagoe, Kitano,Nojiri 02 Hisano,Kawagoe, Nojiri 03 De Sanctis, Laris, Montesano,Troncon 07

20 We consider the following spectrum: m g = 1TeV m C = 300GeV m N = 200GeV The signal is isolated by asking - 2 non-b jet reconstructing a W - W + b jet reconstructing a top m tb - another b jet to make (taking the b jet that give the lowest.) m tb

21 Without combinatoric background pp g g tt b bw W NN σ(pp g g) = 300fb we generated events. 35 susy composite !10 m 2 tb

22 With combinatoric 160 supersymmetric composite ! m 2 tb

23 Comparison to supersymmetry with on-shell decay. t b W g t C N b t W g b C N

24 There is also an endpoint in m bw : m 2 bw endpoint (m2 t m2 C)(m 2 C m 2 N )/m 2 t m t = 500GeV m b = 600GeV supersymmetric composite m g = 1TeV m C = 300GeV m N = 200GeV top cut m bw

25 The stop and sbottom can be produce directly b W + d t N d t C + C N b W Can it be isolated?

26 Conclusions We presented a model with composite gluinos at the TeV scale. This might be generic in this class of models. Could be hard to distinguish from supersymmetry if 3rd generation is lighter than the rest. There is information in the shape of invariant mass distribution, not only in endpoints. If the stop and sbottom can be produced on-shell, the situation seems better.