a selection of exotics with atlas

A Selection of Exoticswith ATLAS

Helenka PrzysiezniakLAPP, Annecy, on behalf of ATLAS

22 April 2002

PHENO2002, 22-24 April 2002Madison, Wisconsin

Why do we need Exotics?

SM - Higgs mechanism does not explain EVERYTHINGN.B. a SUSY talk

Mweak Mplanck ?

Parity Violation? Neutrino masses? Proton decay??

EW symmetry breaking?

Particle mass hierarchy?

Without an abundance of Xtra particles...

P.Higgs

Why do we need ATLAS?(and CMS)

Thin Superconducting Solenoid (B=2T)

LAr Electromagnetic Calorimeter :L R = 13.3m2.25m3.2 (4.9)E /E = 10%/E0.7%

Hadronic Calorimeter :Endcaps LArgBarrel Scintillator-tileL R = 12.2m4.25mE /E = 50%/E3% (3)

Large SuperconductingAir-Core Toroids

Muon SpectrometerL R = 25 (46) m11m

-electrons, jets, Etmiss, E

coverage, b-tagging

Inner Detector :Semiconductor Pixel and StripsStraw Tube Tracking Detector (TRT)L R = 7m1.15mR=12-16m, Z=66-580m

Compositeness (2)

New Gauge Bosons (1)

Strong Symmetry Breaking (3)

Extra Dimensions (4)

And much much more...

Exotics

1.New Gauge Bosons

Parity violation introduced by hand?m = 0 while new experimental data suggest otherwise ?

Left-Right Symmetric Model (LRSM):restores parity symmetry at high energy

and introduces

W+R ,W-

R and Z’

and R-handed neutrinos

Nl

If Majorana ’s , LRSM + SeeSaw 3 light L-handed ’s + 3 heavy R-handed ’s (Nl)

R-handed current contributions to m (KL0 - KS

0): mWR 1.6 TeVTevatron: mZ’ 630 GeV , mWR 720 GeV (light NR) 640 GeV (heavy NR)

-less double decays: mWR 1.1 TeV x (mN /1TeV)-1/4

Search for the decaypp WR eNe

eeW*R ee+qiqj

Most promising channelprod one to two orders of magnitude

higher than Z’

1.New Gauge Bosons

-Discovery potential of pp WR eNe 2e+2jat the 5 confidence level for 30 and 300 fb-1

in m(Ne) vs m(WR) plot using increasingly tighter cuts from a) to c)

For Int. Lumi. 300 fb-1

mWR 4 TeVmNe 6 TeV

Signal 10Signal/Bgd 5

Main backgrounds:

jetseejets/Z

bbWWttZZ,ZW,WW

pp*

2.Compositeness

1-2-3 generations of quarks and leptonsPossibly composite structures?

More fundamental constituents?

Excited (spin 1/2,...) quarks and leptons,Leptoquarks,Diquarks,Dileptons,etc…

Direct production of excited spin 1/2 fermions for s (~m*)f, f’, fs Lagrangian term constants determined by the compositeness dynamics

e.g.Excited quarks1st generation u,d

*

q g

qWq g q

q Z

q

BR80%BR12%BR5%BR<5%

CDF searches: 200m*760 GeV combined excluded

D0 searches: 200m*720 GeV excluded

f=f’=fs=1

2.CompositenessExcited quarks of spin 1/2

qg q* q channel

Main backgrounds:

Invariant mass distributions mj for the excited quark signal and backgrounds for =m* =1TeV

W'qq,Zqqggg,qqg,gqq

Signal 10 per yearSignal/Bgd 5 per year

f=f’=fs=1


m* 6.5 TeV

Excited quark signal significance (left) 300 fb-1

3.Strong Symmetry Breaking

Breaking of EW symmetry?Regularization of the quadri-vector boson coupling?

Mechanism for generating mf ?

Understanding EW symmetry breaking:

Search for new resonances(which could regularize vector boson scattering Xsection)

Study Longitudinal gauge boson pair production(L component provides mass to bosons)

e.g.1. Technicolore.g.2. Chiral Lagrangian model


e.g.1.Technicolor

Classical TCGoldstone bosons T are longitudinal d.o.f of W and Z

largely ruled out by precision EW dataExtended TC

allows generation of mf

does not explain absence of FCNCWalking ETC

«walking» coupling constant TC

several representations of fundamental familyexistence of technihadron resonances

Constraints from EW data make it unnatural to explain mTop

for all of the above models

Top-color-assisted TCmTop arises from new strong top-color interaction

3.Strong Symmetry Breakinge.g.1.Technicolor

Channels investigated

Cleanest channel of those with direct production of T bb resonances

tt resonances

Mass scenarios considered

Main backgrounds:1. WZ continuum production

2. Z+jets (qqgZ,qg qZ,qq ZZ)ttbar, WZ continuum production

(qqbar WZ)

Direct production of T

3.Strong Symmetry Breakinge.g.1.Technicolor

Direct production of T

Lower limits required for 5significance with 30 fb-1 :

in some cases,signals are below observability,

but combination of signalscould provide strong evidence.

Reconstructed invariant mass for TWZlll channel.Solid line is signal. Filled area is background.

TWZlll for 30 fb-1

(a) xBRmodel = 0.16 fbxBR5 discovery = 0.025 fb

TWlbb for 30 fb-1

(c) xBRmodel = 0.064 fbxBR5 discovery = 0.15 fb

4.Extra Dimensions

Large (1mm,1/TeV) Xtra D’s«à la» Arkani Dimopoulos Dvali - MEff

PlanckMweak

Gravity propagates in the Xtra DsHence its weakness: it is diluted into the Xtra Ds

Direct or virtual production of Gravitons

TeV-1 Xtra D’sSM gauge fields propagate in «small» Xtra Ds

4D KK excitations of gauge fields

Small Xtra D’s«à la» Randall Sundrum - MEff

PlanckMweak

«warped» metric - only 1 Xtra D4D KK excitations of Graviton

Higgs-like Radion scalar

etc...

4.Extra DimensionsLarge Xtra D’s (ADD)

Graviton direct productionjet() + ET

miss signature

2D

1N MR8G

ETmiss for signal and background for 100 fb-1

Gqq

Single jet:

Single (limited sensitivity):

Ggqq,qGqg,gGgg

With Xtra D’s of size R,observed Newton constant related to

fundamental scale of gravity MD:

Main backgrounds:jet+Z(), jet+Wjet+(e,,)

Main backgrounds:Z(), W(), W (e,,)

4.Extra DimensionsLarge Xtra D’s (ADD)

Max reach in MD for 100 fb-1

for a jet of ET>ETmiss

for Smax=S/B>5 and Smin=S/7B>5and for S>100

Single jet channel

: exploit variation of vs Ecm

(Ecm1)/ (Ecm2) almost independent of MD

but varies with

100 fb-1 high lumiSmax>5, S>100, ET>1TeV

for =2,3,4MD

max = 9.1, 7.0 and 6.0 TeV

4.Extra DimensionsTeV-1 Xtra D’s

Usual 4D + Small (TeV-1) Xtra D’s + Large Xtra D’s (>>TeV-1):

fermions live in 3-brane, Gravitons go everywhere,SM gauge bosons propagate in 4D+Small Xtra D’s

4D KK excitations of gauge bosons (here: 1 small Xtra D)

100 fb-1 high lumiPeak in mll detected if

Mc < 5.8 TeV

300 fb-1 high lumiMc< 13.5 TeV

excluded@95%C.L.


Mll for e+e- (full line) and + (dashed).Lowest lying KK excitation at 4 TeV.

Mc compactification scaleMasses of gauge bosons KK modes:

Mn2

= (nMc)2+M02

e+e-, +- decays of and Z bosons

Exponentially warped fifth dimension:

Two massless excitations: Graviscalar Graviton

Radion

1/k curvature radius(k of order of Planck scale)

rc volume radius

4.Extra DimensionsSmall Xtra D’s (RS)

Universe with two 4-d surfacesbounding a slice of 5-d spacetime

SM fields live on TeV brane (y=)Gravity lives everywhere:

TeV (y=), Planck (y=0) branes and in the bulk

22c

|y|kr22 dyrdxdxeds c

35~rkM/M

emm

cPlanckweak

kr0

c

4.Extra DimensionsSmall Xtra D’s (RS)Higgs-like Radion scalar

Three parameters:m , ,

(mass,scale,-H mixing)

Channels investigated: , ZZ(*) 4 leptons

hh bb,bb

Mechanismnaturally stabilizing size of Xtra Dto krc=35 (Goldberger & Wise):

add bulk scalar radion scalar most likely lighter than

J=2 Kaluza Klein excitations.

Log(BR) vs mass of scalar for SM Higgs (top)and for radion =0 (middle) and =0 (bottom),

for =1 TeV, mh =125 GeV.

4.Extra DimensionsSmall Xtra D’s (RS)

Higgs-like Radion scalar

30fb-1 , = 0, mh=125 GeV/c2

->hh->bbIf B=0, Signal/Bgd>5, Signal>10

max=4.6 5.7 TeV

for m= 300 600 GeV/c2

30fb-1 , = 0, mh=125 GeV/c2

->hh->bb Signal/Bgd>5, Signal>10

max=1.4TeV form= 600 GeV/c2

100fb-1, = 0, mh=125 GeV/c2, = 1(10) TeV S/B~10(.1) for 80<m<160 GeV/c2

ZZ(*) S/B~100(1) for 200<m<600 GeV/c2

Conclusion and Outlook

Un? biased selection ofExotics studies with ATLAS:

Lots going on in Xtra D ’s

Theory advancing at TGV pacee.g. black hole production @ LHC!!!

Experimentalists try to follow

LHC will definitely berich discovery terrain !!

Annexe-Add references and names for models and for analyses?

-Give Tevatron (LEP and other) limits when they exist-are the atlas limits @95%CL or 90%?

-Int. Lumi for low and high lumi running???-Mention for each analysis the experimental signatures and cuts

-put main background for each analysis-mention authors of theories

-add analysis by Polesello and Azuelos-add technicolor and other Tevatron limits

(those for Azuelos+Polesello analysis from the lesh proc)-check for ??? Everywhere and answer them...

AnnexeLAr Electromagnetic Calorimeter :

E /E = 10%/E???%/E0.7%(sampling+electronics and pile up+non uniformity constant)

thickness>24Xo in barrel and >26Xo in endcapsHadronic Calorimeter :LAr Hadronic endcaps

Scintillator-tile barrel (thickness 9.2 at =0)

complete???

Annexe

1.New Gauge Bosons

Parity violation introduced by hand?m = 0 while new experimental data suggest otherwise ?

Left-Right Symmetric Model (LRSM):broken symmetry parity violation @ low energy

restores parity symmetry at high energy by extendingSU(2)L U(1)Y SU(2)L SU(2)R U(1)B-L

and thereby introducing:W+

R ,W-R and Z’

as well as right-handed neutrinosNl

If Majorana ’s , LRSM + SeeSaw mechanism 3 light left-handed ’s + 3 heavy right-handed ’s (Nl) R-handed current contributions to KL

0 - KS0 m : mWR 1.6 TeV

Tevatron: mZ’ 630 GeV , mWR 720 GeV (light NR) 640 GeV (heavy NR)

-less double decays: mWR 1.1 TeV x (mN /1TeV)-1/4

Annexe1.New Gauge Bosons

Search for the decaypp Z’ NeNe eW*

ReW*R ee+qiqjq’iq’j

- -

Observability of pp Z' Ne Ne 2e+4jetsat the 5 confidence level for 300 fb-1

in m(Ne) vs m(Z') plot


for m(N)/m(Z’) 0.1


mZ’ 4.3 TeVmNe 1.2 GeV

Main backgrounds:

jetseejetstt,NN,,ee'ZN,eNW

pp:LRSM

jetseejets/Z

bbWWttZZ,ZW,WW

pp:SM

eR

*

Annexe1.New Gauge Bosons

Search for the decaypp W’ WZ

Not principal discovery channel

Ratio of cross section required for a 5significance over that of the SM???


mW’ 2.8 TeV

In LRSM,if WR is not kinematically allowed

to decay to lepton + NR

Main backgrounds:

ZZWZ

bjbbWWttpp

Leptonic channel:weak sensitivity to mixing angle

All channels: Z’WW

sensitive to sin

Annexe1.New Gauge BosonsSearch for the decay

pp W’ WZE6 model: Z’=cos Z + sin Z

Not principal discovery channel

Unpublished

Total decay width and relative BR=(q* qV)/V (q* qV)

Annexe2.Compositeness

Excited quarks of spin 1/2


Excited quarks of spin 1/2qg q* qg



m* 6.6 TeV

Signal significance vs =m*

Invariant mass distributions mjj

for f=f’=fs=1 (dashed),f=f’=fs=0.5 (dashed dotted),backgrounds (solid) for =m* =2TeV

Main backgrounds:

qqgg,ggggqgqg,ggqq,qqqq

Annexe 2.CompositenessExcited leptons

eWeeqqeZeeeqq

*

*

Zee channel Signal 5

Signal/Bgd 5f=f’=1


m* = 3 TeV


m* = 3 TeV

We channelSignal 100

f=f’=1

Signal significance vs =m* for 300 fb-1

Zeeeeee channel

Unpublished


Excited quarks of spin 1/2

fqfqZq'fqfqWq

*

*


m* 7 TeV qW channel

m* 4.5 TeV qZ channel

Signal significance for the qW channel (solid lines)and for the qZ channel (dashed lines)Unpublished

Annexe


Breaking of EW symmetry?Regularization of the quadri-vector boson coupling?

Mechanism for generating mf ?«Triviality»???:

impossible to construct interacting theory of scalars in 4dwhich is valid to arbitrary short distance scales

(problem is absent in SUSY models).

Understanding EW symmetry breaking:

Study Longitudinal gauge boson pair production in high energy regime(since it is the L component which provides mass to these bosons)

Search for new resonances(which could regularize vector boson scattering Xsection)

Annexe3.Strong Symmetry Breaking

e.g.1.Technicolor

Classical TCGoldstone bosons T are longitudinal d.o.f of W and Z, replica of QCD

largely ruled out by precision EW dataExtended TC

allows generation of mf

does not explain absence of FCNCWalking ETC

«walking» coupling constant TC ,several representations of fundamental family ,

existence of technihadron resonances

Constraints from EW data make it unnatural to explain mTop

in all these models

Top-color-assisted TCmTop arises from new strong top-color interaction

T Tbb for 30 fb-1

m=500 (800) GeV: xBRmodel = 0.161 (0.033) fb

Signal/Bgd=60 (35)xBR5 discovery = 0.013 (0.0046) fb


e.g.1.TechnicolorObservability of other channels

tt resonances 10 (100) fb-1

mtt=500GeV: xBR5 discovery = 17 (5.5) fbmtt=750GeV: xBR5 discovery = 7.3 (2.3) fb

mtt=1000GeV: xBR5 discovery = 2.55 (0.81) fb


e.g.1.TechnicolorObservability of channels

Expected significance, xBR (fb) predicted by model,xBR required for 5 significance, for WZlll for 30 fb-1.

Expected significance, xBR (fb) predicted by model,xBR required for 5 significance, for Wlbb for 30 fb-1

Minimum values of xBR (fb) necessary for a 5 discovery, for tt resonances,

for 10 fb-1 and 100 fb-1

Expected significance, xBR (fb) predicted by model,xBR required for 5 significance,

for bb for 30 fb-1


e.g.1.TechnicolorT production via WLZL fusion

Quark fusion process dominates,but vector boson fusion has forward jet tag

which helps to suppress background.Complementary channel to fusion.

Observability of qqqq T qq W T

0

xBRmodel = 2.2 fbSignal/Bgd=1.1 versus

Signal/Bgd=2.1 in direct production.xBR5 discovery = 12 fb

qq

ZL(WL)

qq qqT qqWT

0

qqlbb

Main backgrounds(same as direct prod):

1. WZ continuum production2. Z+jets (qqgZ,qg qZ,qq ZZ)ttbar, WZ continuum production


e.g.2.Chiral Lagrangian model

Based on Chiral Perturbation Theory (ChPT)Study WL WL scattering

Inverse Amplitude Method (IAM) : parameters L1 and L2

Unitarity is not violatedIAM model predicts resonances for certain parameter values

Resonant WL ZL WL

ZL scattering??? What values of L1 and L2 in the plot???

Main backgrounds:1. Irreducible continuum WZ (negligible), 2. Reducible QCD

(e.g. main Z+jets,ttbarWWbbbar)

Nsignal=8 14for MRes= 1.5 1.2 TeV

Nbackground=1.3 3for 30 fb-1

MRes= 1.5 TeV for qqqqWZ qqjjll


e.g.2.Chiral Lagrangian model

Based on Chiral Perturbation Theory (ChPT)Effective Chiral Lagrangian with operators up to dimension 4.

Study WL WL scattering.The Inverse Amplitude Method (IAM) with parameters L1 and L2

used such that Unitarity is not violated.For certain values of the parameters, IAM model predicts resonances.

Resonant WL ZL WL

ZL scattering

lljjqqqqWZqq Nsignal=8 (14)

for MV = 1.5 (1.2) TeVNbackground=1.3 (3)

for 30 fb-1

Annexe 3.Strong Symmetry Breakinge.g.2.Chiral Lagrangian model

Non resonant WL+WL

+ and WL ZL WL

ZL processesIAM model parameters L1 and L2

for 500 fb-1 !! L1=0.003 (0.01) and L2=0Signal/Bgd=2.7 (1.43)

MT of WZ system for signal and backgroundsfor 500 fb-1.

WL ZL WL

ZL lll

MT of ll+Etmiss for signal (continuous:K matrix unit.

and dashed: 1TeV Higgs)and backgrounds (full histo) for 100 fb-1 ???

WL+WL

+ l+l-

Main backgrounds:1. Irreducible continuum WZ, 2. Reducible QCD(e.g. main Z+ttbarZ+WWbbbar Z+lWbbbar)

Main backgrounds:1. Irreducible continuum WTWT

bremsstrahlung, gluon exchange,Wttbar, WZ

Annexe4.Extra Dimensions

Large Xtra D’s (ADD)

If MD~1TeV then R~1032/-16 mm implying that if 2,R is smaller than the scales of order 1mm down to which gravitational

interactions have been probed.=1 excluded since it would imply deviations of the Newton law of gravity.=2 is not very likely because of cosmological arguments, in particular

graviton emission from Supernovae 1987a implies that MD>50 TeV.

In this picture, the apparent weakness of observed gravity is due to its dilutionby the spreading of its field into the additional dimensions.

It should be noted that the hierarchy problem is not solved in the simplestimplementation of the idea; the large ratio MP/MW is replaced by the large value

of RMD .When an Xtra D is compactified on a circle with size R,particles propagating exclusively in the Xtra D appear, from a 4d viewpoint,

as a tower of massive states. The charactersitic mass splitting of theseKK states is of the order of 1/R. In particular spin 2 gravitons propagating in the

Xtra D will appear to be massive states whose coupling to ordinary matteris determined only by gravitational interactions and is therefore known.However the SM particles cannot be allowed to propagate into the Xtra D

as there is not excited electron with a mass below 100 GeV.

For energies much larger than the mass splitting, the discrete spectrum can beapproximated by a continuum with a density of states dN/dm~m-1.

Since these gravitons interact very weakly with ordinary matter, the emissiongives rise to missing transverse energy signatures.



: exploit variation of vs Ecm

(Ecm1)/ (Ecm2) almost independent of MD

but varies with

100 fb-1 high lumiSmax>5, S>100, ET>1TeV

for =2,3,4MD

max = 9.1, 7.0 and 6.0 TeV

30 fb-1 low lumi, ‘’, S>50MD

max = 7.7, 6.2 and 5.2 TeV

Annexe 4.Extra DimensionsLarge Xtra D’s (ADD)

Virtual Exchangein particular and lepton pair production.

deviations in Drell-Yan Xsec. and Asym. w.r.t. SM

Low (high) lumi, =52

Di-photon:MD

max = 4.9-6.3 (6.3-7.9) TeVDi-lepton:

MDmax = 5.1-6.6 (6.6-7.9) TeV

Lower cut ???Mmin vs maximal reach MD at 5 level for low lumi 10 fb-1 (solid)

and high lumi 100 fb-1 (dashed).

4500 8000

1000

5000

N.B. cannot really distinguish number of Xtra D and energy scale



Di photon invariant mass.Total signal for n=3 and various values

of Ms (left), for Ms=4.7 TeV andvarious values of n (right).

FB asymmetry vs Mll for n=3and various values of Ms (left),

for Ms=4.7 TeV andvarious values of n (right).

Errors are presented bygrey bars except for n=2,

and correspond to 100 fb-1 .

4.Extra DimensionsTeV-1 Xtra D’s

Usual 4D + Small (TeV-1) Xtra D’s + Large Xtra D’s (>>TeV-1):

fermions live on 3 brane,Gravitons live everywhere,

SM gauge bosons propagate in 4D+Small Xtra D’s 4D KK excitations of gauge bosons (here: 1 small Xtra D)

Model completely specified by Mc

compactification scale:masses of the KK modes of gauge bosons

Mn2

= (nMc)2+M02

e+e-, +- decays of and Z bosons striking signature


TeV-1 Xtra D’s

Precision EW measurements give Mc< 4 TeV excluded @95% C.L.

for the reference model considered here.Recent paper dominated by LEP2 data gives

Mc< 6.8 TeV excluded @95% C.L.but certain inconsistencies in this result,

namely an unphysical negative value for Mc is obtained.

Scale:

where is the reduced 4d Planck scale.

Masses of graviton resonances:

where xn are roots of Bessel function of order 1.

Couplings 1/

low coupling constant: conservative estimate of prod

narrow resonances

)M/k(xekxm Plnkr

nnc

01.0M/k Pl

ckrPleM

PlM

crk35 e

k

M24or

Annexe4.Extra DimensionsSmall Xtra D’s (RS)

KK Graviton excitations: narrow multi TeV resonances

Annexe 4.Extra DimensionsSmall Xtra D’s (RS)

KK Graviton excitations: narrow multi TeV resonancesG e+ e- decay mode

«model independent» study

Assuming resonance mdet

Nsignalmin =max(5NBgd ,10)

for 100 fb-1

BR (fb) vs MG for G e+ e- in the test

model and BR (fb) for signal significance Smallest BR (fb) vs MG for G e+ e-

for which the spin-2 hypothesis is favouredover the spin-1 hypothesis, @90,95 and 99% C.L.

The test BR (fb) is also shown.

Angular distribution of data (points) in test model for mG =1000 GeV and 100 fb-1

Stacked histo shows contributions from SM, gg and qq prod. Curve shows distributionexpeced from spin=1 resonance.

Annexe4.Extra DimensionsSmall Xtra D’s (RS)

KK Graviton excitations: narrow multi TeV resonancesG e+ e- decay mode

«model independent» study

AnnexeLepton Flavour Violation

Super K results suggest - mixing LFV.

In SUSY models, LFV may have implications for the pattern of slepton masses and mixings.

LFV introduced into SUSY at one loop levelR-handed ’s coupling to the lepton L-handed doublets (NiLjH)

One loop rad. corr. LNumberV terms in mass matrices for L-sleptons.

Minimal SUGRA decays:(ATLAS point 5: m0=100GeV, m1/2=300GeV, A0=300GeV,tan=10 and sgn =+)

Without LFV: With LFV:

LFV decays give a signalproducing an asymmetry between and efinal states

01

02

~~~1

LFV

01

02

~~~LFV

1

01

LFV1

LFV

02

~~~)e~()~(

~~~q~

01

01

01

02 1

Unseparable

Small BR

Annexe Lepton Flavour Violation

Minimal SUGRA+LFVsignal search

Search for multiple jets and ETmiss

and look at opposte sign dilepton Mll

Visible mass distributionsl+-h

-+ - l+-h+- (solid line)

and +-h-+ from LFV with BR=10%

(dashed-dotted line).SM bgd cancel in this plot.

decaysensitive to the same LFVas signal considered here

giving BR()110-9

AnnexeSuper LHC

5 discovery limits achieved on MD in TeV.

Search for new gauge bosons

5 discovery limits for Z’ mass in TeV in the +- channel.

Excited quarks

Large Xtra Ds direct Graviton production

Significance of q*q vs mq*.

a selection of exotics with atlas

Documents

heavy rhanded s nl r

parity symmetry

strong symmetry breakinge

e coverage

high energyand introducesw

f of w

compositeness dynamics

new experimental data