SUSY and BSM in ATLAS Recent Results and more selected topics - - PowerPoint PPT Presentation

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SUSY and BSM in ATLAS Recent Results and more selected topics - - PowerPoint PPT Presentation

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SUSY and BSM in ATLAS Recent Results and more selected topics only!!! G. Azuelos Supersymmetry BSM inclusive signals: narrow resonances: Jets + Etmiss dileptons + 0, 1, 2 leptons lepton +MET multileptons

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SUSY and BSM in ATLAS Recent Results and more selected topics only!!!

  • G. Azuelos

BSM

  • narrow resonances:
  • dileptons
  • lepton +MET
  • dijets
  • diphotons
  • heavy quarks
  • Monojets
  • Leptoquarks

Supersymmetry

  • inclusive signals:
  • Jets + Etmiss
  • … + 0, 1, 2 leptons
  • multileptons
  • stable hadronizing particles
  • GMSB
  • displaced vertices
  • diphotons + MET
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Introduction

 Beyond the Standard Model

  • wide variety of models and signatures, with unknown parameters
  • exclude regions of parameter space
  • interpret a signature in terms of different models
  • narrow resonances relatively easy
  • knowledge of background less critical
  • non-resonant signals probe high mass phenomena
  • where the backgrounds are low and where backgrounds,

reconstruction efficiencies are well understood

 Supersymmetry

  • very large parameter space  initial study of simplest models
  • inclusive signals: excess in jets, Etmiss (and leptons)
  • R-parity violation
  • long-lived particles
  • interpretation in terms mostly of SUGRA (5 parameters), but also

GMSB, (AMSB)

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Experimental Challenges

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 see talk by Michel Lefebvre

Impossible to discuss experimental methods in each case

Systematic errors:

  • NLO, NNLO calculations, mass-dependent k-factors
  • matching of matrix element and parton shower (for multijet processes)
  • pdf, alpha_s, QCD scale factors
  • QCD, W+jets have high cross sections  data driven techniques, with their

uncertaintes

  • lepton reconstruction efficiencies, isolation, resolution
  • Good Runs Lists…
  • pileup reweighting
  • luminosity
  • limit extraction procedure
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Narrow Dilepton resonances

 Sequential Standard Model

  • generic Z’ with SM couplings to fermions but no coupling to gauge bosons
  • serves as a benchmark

 E6-inspired Z’ (and other gauge symmetry extensions)

  •  Graviton KK

 technirho, techniomega  Various other models….

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10 | 1 1 5 ( ) ( ( ) ( ) ) E SO SU U U

ψ χ

→ + → +

1 6 1 6 1 6 1 6

5 3 3 5 15 9 15 tan tan tan tan

I E N E E E S

Z Z Z Z

η

π

− − − −

θ = − ⇒ θ = ⇒ θ = ⇒ θ = ′ ⇒ ′ ′ ′

6 6

' cos sin

E E

Z Z Z

χ ψ χ ψ

+ θ ′ θ ′ = Z KK , Z *, 3- 3-1, little Higgs Z H , LRSM Stueckelberg Z ', leptophobic or fermiophobic Z '

  • P. Langacker, Rev Mod Phys 81 (2009) 1199
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Resonant dileptons

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arXiv:1108.1582 Drell-Yan production well predicted NNLO calculations available; used to derive mass-dependent derive k-factors Other backgrounds estimated by data-driven method or by MC

  • multijets: reverse isolation
  • W+jets
  • top pair
  • dibosons

Background scaled to data in Z peak region uncertainties:

  • k- factors, pdf’s
  • normalization
  • trigger/reconstruction
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Limits on dilepton resonances

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95% CL limits

Low Scale Technicolor

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Contact Interactions

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L = g 2 2! 2 "LL # !L$ µ! L #qL$ µqL + 2"LR # !L$ µ! L #qR$ µqR + "RR # !R$ µ! R #qR$ µqR % & ' ( g = 4!

( )

All quarks participate in contact interaction with the same strength. Interference very important (dominant) d! dm!! = d! DY dm!! " #LL F

I (m!!)

$ 2 + F

C (m!!)

$ 4

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Diphotons

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New Large Extra Dimensions: virtual graviton exchange

! ! "G = F MS

4

backgrounds

  • prompt photons (pythia, DIPHOX for NLO)
  • fakes:  + j, j j by choosing non-tight photons
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diphotons – Bounds on RS Graviton

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W’

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Sequential Standard Model used as benchmark

mT = 2pTET

miss(1! cos" !# )

mass-dependent k-factors to NNLO

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SLIDE 11

dijet resonance search

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Various models

  • excited quark q* (contact interaction)
  • axigluon: axial coupling to quarks
  • color-octet scalar

qg ! q* " compositeness scale # $ mq*

LAqq = gQCDq Aµ

a !a

2 " µ" 5 q; gQCD = 4#$s

Lgg8 = gQCD d ABC ! s "s S8

AFµ# BFC ,µ#

F

µ# B = gluon field strength tensor (color index A)

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dijets

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q* and A8

S8

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4th family quarks

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from same sign dilepton events

d4d4 !W "tW +t

u4u4 !W +bW "b

… more soon with higher luminosity

SM 4th family quarks

  • allow the Higgs mass to be heavy (but now excluded…)
  • cannot be too heavy without causing vacuum instability or violation of perturbative unitarity
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Vector-Like Quarks coupling to light generations

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New

vector-like quarks:

  • both chiralities have the same transformation properties: singlets or doublets in SU(2)
  • predicted by many models
  • E6 : down-type quarks
  • DEWSB: little Higgs, top condensation, beautiful mirrors, composite Higgs
  • extra dimensions, for even number of spatial dimensions
  • EW constraints
  • expected generally to couple to 3rd generation because less contrained
  • in certain scenarios, mixings with SM quarks can cancel

 no EWPM constraint from first generations  strong signal at LHC

  • motivation
  • BSM models with custodial symmetry to protect Zbb

(Agashe et al., Physics Letters B 641 (2006) 62–66)

  • extra dimension models
  • composite Higgs model

(M Redi and A. Weiler, JHEP11 (2011) 108 ) CMS has looked for T  t Z in pair production (Z + 1 lepton): mT > 475 GeV if 100% BR arXiv:1109.4985

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vector-like quarks

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single production more sensitive dominated by t-channel  forward jet both charged and neutral current channels

L = g 2 ! uDWµ

+ uR" µDR +! dU Wµ # dR" µUR

( ) +

g 2cos$W ! uUuR" µUR +! dDdR" µDR

( )

! ! = v M ! ! ! = 1 BR(D " Wu)=100% ! ! = 1 BR(U ! Zu)=100%

(only RH coupling shown, for doublet vlq)

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vlq

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! ! = 1 BR(D " Wu)=100% ! ! = 1 BR(U ! Zu)=100%

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constraints on coupling in degenerate bi-doublet model

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  • A. Atre et al.,

Degenerate bidoublet: hypercharges 1/6 and 7/6 same Yukawa couplings to SM u quark. Mixing of up with the two charge 2/3 quarks cancel exactly, leaving no

  • bservable correction to

SM coupling

(2,2) in SU (2)L !SU (2)R

X5/3 X'2/3 ! " # # $ % & & and U 2/3 D'1/3 ! " # # $ % & &

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Monojets

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High pT Jet recoiling against an invisible particle such as

  • graviton in ADD model of large extra dimensions
  • Wimp pairs

3 regions selected: LowPT, HighPT, VeryHighPT

  • pt(j1) > 120, 250, 350 GeV
  • MET > 120, 220, 300 GeV
  • pt(j2) < 30, 60, 60 GeV

Z+j, W+j are dominant backgrounds, but also QCD (data driven) and beam related background High PT region

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limits on ADD

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Limit on MD depends on the number of extra dimensions Validity of the theory breaks when  truncate phase space for cross section evaluation  changes the limit by a few percent

s ~ MD

Model-independent cross section limit (95% CL) 2.02 pb, 0.13 pb and 0.045 pb for the LowPt, HighPt and veryHighPt regions

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monojets and dark matter

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 see seminar by W. Shepherd on Monday

Assume effective interaction qq due to exchange of heavy particle

  • coupling can be scalar, vector, axial-

vector…, can involve gluons

  • the same coupling (diagram) applies

to dark matter direct detection:  + (A,Z)   + (A,Z)

  • interpret the LHC limit in terms of

WIMP cross section on nucleons

  • very good sensitivity to spin-

dependent interactions

  • also to spin-independent interaction

for low mass WIMP Bai, Fox and Harnik, 1005.3797

  • J. Goodman et al., 1008.1783

Akula et al., 1103.5061

  • J. Goodman and W. Shepherd, 1111.2359

1008.1783

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scalar Leptoquarks

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showing the 35pb-1 analysis New results coming out very soon…

clean, simple signal pair production cross section is (almost) model-independent

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scalar Leptoquarks

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similar limit contour for muon channels

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SLIDE 23

Other interesting BSM topics…

 Diboson resonances

  • Neutral resonances
  • Signals similar to Higgs, but could be vector or tensor
  • Charged resonances

 Left-Right Symmetric model

  • WR and heavy Majorana neutrino

 strong gravity, black holes, ttbar charge asymmetry,  many others …

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G* ! ZZ ! 4! or 2!2j or 2! + MET " Z or #T or G* ! WW ! !$!$ or !$jj

! W or !T or G* "WZ " !!!! or !!jj or !!jj

Results coming out soon…

ATLAS-CONF-2011-115

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Summary Tables

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Supersymmetry: jets, MET and leptons

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! qL

l

! !2

! "R

q

! !1

l

! g ! ! q q | ! " ±q | ! "# ! "1

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Jets, MET and no lepton

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2 jets 3 jets 4 jets

4 jets high mass

ET

miss > 130 GeV

pT (jet1) > 130 GeV pT (jet2+) > 40 GeV meff > 1000 GeV

meff ! ET

miss +

pT (jets)

"

high mass:

pT (jet2+) > 80 GeV meff > 1100 GeV

signal: m0 = 660 GeV, m1/2 = 240 GeV, A0 = 0, tan! = 10, µ > 0

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Jets + ETmiss

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simplified model: m(! !1

0) = 0

  • ther particles heavy
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High Jet multiplicity + MET

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6 or more jets QCD background from control regions with fewer jets (MET/sqrt(HT) ~ independent of number of jets)

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additional model interpretation

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considered direct decays

  • r 2-step processes

! q ! q ! q "1

0 q "1

! g ! g ! qq "1

0 qq "1

! q ! q ! "1

± ! qW (*) !

"1 ! g ! qq ! "1

± ! qqW (*) !

"1

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UED

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Similarity between SUSY and UED

  • partner or KK state (but spin is different)
  • conservation of R parity or KK state
  • LSP or LKP escapes detection

UED characterized by compactification radius R and cut-off scale  > R-1 radiative correction ~ ln( R)

mKK = mSM

2

+ R!2

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Jets + Etmiss + 1 lepton

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at least 3 jets cuts on MET, mT also limits on model with bilinear RPV

meff = pT

! +

pT

jeti + ET miss i=1 3(4)

!

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simplified model with 1-lepton

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! q ! q ! "1

± ! qW (*) !

"1 ! g ! qq ! "1

± ! qqW (*) !

"1

x = m !

! ± "m ! ! 0

m !

g "m ! ! 0

x = 1

4

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transparency from Ryuichi Ueno, https://indico.cern.ch/getFile.py/access?contribId=16&sessionId=3&resId=0&materialId=slides&confId=161358

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Jets + MET + 2 leptons

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Limits obtained on production cross section for same-sign and for

  • pposite sign lepton

pairs

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SLIDE 35

GMSB interpretation – jets + MET + 2 leptons

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Gauge Mediated Supersymmetry breaking parameters

! : SUSY breaking scale in separate sector ! MPlanck tan" : ratio of vevs Mmess : mass scale of messenger fields = 250 GeV~ weak scale N5 : number of messenger fields = 5 sgn(µ): sign of Higgsino mass term > 0 Cgrav : multiplicative factor of gravitino mass

exactly 2 leptons of opposite charge m!! > 12 GeV ET

miss > 220 GeV

at least 3 jets with pT1 > 80 GeV and other pT (jets) > 40 GeV

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SLIDE 36

Selection

  • at least 3 leptons
  • pT1, pT2 > 20 GeV, pT3>20(10) for e, µ
  • at least 2 jets with pT > 50 GeV
  • MET > 50 GeV
  • Z veto
  • low mass DY rejected (mll >20 GeV) for SFOS pairs

multileptons

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Showing the 35 pb-1 result. More recent result will be available soon…

  • Low background
  • CMS sees some excess (1106.0933) in 3 and 4-lepton channels
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SLIDE 37

multileptons

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MSUGRA PhenoGrid2: light neutralino

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SLIDE 38

b-jet + MET + 0l

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large mixing with 3rd generation squarks can result in low mass eigenstate

Scenarios:

! bL ! ! bR or ! tL ! ! tR

1) ! g ! ! b1b m !

"1

0 = 60 GeV

| !b ! "1 2) ! g !bb ! "1

0 (off-shell)

3) SO(10) # inspired: ! g !bb ! "1

0 and !

g !bb ! " 2

0 are dominant

(D-term and Higgs splitting models)

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b-jet + MET + 0l

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at least 3 jets: pT1 > 130 GeV, pT 3 > 50 GeV at least one jet is b-tagged ET

miss > 130 GeV

ET

miss meff > 0.25

!"ET

miss# jet > 0.4

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b-jet + MET + 1 lepton

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1) ! g ! ! t1t m !

!1

0 = 60 GeV

| !b ! !1

± !b !

!1

0!!

2) ! g ! tt ! !1

0 (off-shell)

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Displaced vertices: R-Parity Violation

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diphotons + MET

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One of the first ATLAS papers, where signal was interpreted in terms of UED 2 tight isolated photons with ET > 25 GeV and MET > 125 GeV 5 events found, 4.1 expected Here, 3 scenarios:

GGM: Generalized GMSB Minimal GMSB: SPS8 Universal Extra Dimensions

If NLSP is bino, ! !1

0 " # !

G

Heavy squarks and gluinos !: only free parameter Mmess = 2!; N5 = 1; tan" = 15; µ > 0

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GGM

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SPS8 and UED

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Summary Table - SUSY

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MSSM: > 100 parameters

Minimal Flavour Violation: 13 parameters

(+ 6 violating CP)

SU(5) unification: 7 parameters

NUHM2: 6 parameters NUHM1 = SO(10): 5 parameters CMSSM: 4 parameters

mSUGRA: 3 parameters

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Conclusion

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2012 is poised to be 
 a fantastic year!

(but the Higgs??)

slides from Bertolucci and deJog, at LHCP

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backups

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WR

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ATLAS-CONF-2011-115

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long-lived particles

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long-lived particles

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arXiv:1103.1984v1

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strong gravity from ss dimuons

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bounds on MWT parameters from W’ and Z’

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t

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J R Andersen, T Hapola and F Sannino, arXiv:1105.1433

Tevatron, from e+e- ew params W & Y

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