Transcript Prospects for SUSY at ATLAS and CMS

Beyond the Standard Model
at ATLAS
Dan Tovey
University of Sheffield
Dan Tovey
1
Freiburg, October 2004
Beyond the Standard Model
• Beyond the Standard Model physics one of the
priorities of on-going physics studies (Data
Challenges/full-sim + fast-sim).
• Huge variety of models being studied.
• In this talk will concentrate on a few topics  mostly
recent work.
• Cannot do justice to even these in 30 minutes.
• Will highlight models and techniques to be studied
for Rome.
– Plans for physics commissioning studied (SUSY) described
earlier this week (Saturday).
• Many thanks to Georges Azuelos, Samir Ferrag +
members of SUSY & Exotics WG’s.
Dan Tovey
2
Freiburg, October 2004
Supersymmetry
• SUSY particularly wellmotivated solution to gauge
hierarchy problem,
unification of couplings etc.
• Also often provides natural
solution to Dark Matter
problem of
astrophysics/cosmology.
• Much work carried out
historically by ATLAS
(summarised in TDR).
• Work continuing to ensure
ready to test new ideas in
2007.
m1/2 (GeV)
Universe Over-Closed
m0 (GeV)
Dan Tovey
3
Freiburg, October 2004
SUSY Signatures
• Q: What do we expect SUSY events @ LHC to look like?
• A: Look at typical decay chain:
p
p
~
g
q
~
q
~
c0 2
q
~
c0 1
~
l
l
l
• Strongly interacting sparticles (squarks, gluinos) dominate
production.
• Heavier than sleptons, gauginos etc. g cascade decays to LSP.
• Long decay chains and large mass differences between SUSY states
– Many high pT objects observed (leptons, jets, b-jets).
• If R-Parity conserved LSP (lightest neutralino in mSUGRA) stable
and sparticles pair produced.
– Large ETmiss signature (c.f. Wgln).
• Closest equivalent SM signature tgWb.
Dan Tovey
4
Freiburg, October 2004
Dilepton Edge Measurements
• When kinematically
accessible ~
c02 can undergo
sequential two-body decay
to ~
c01 via a right-slepton
(e.g. LHC Point 5).
• Results in sharp OS SF
dilepton invariant mass
edge sensitive to
combination of masses of
sparticles.
• Can perform SM & SUSY
background subtraction
using OF distribution
c~02
l
c~01
l
e+e- + m+m- e+m- - m+e-
e+e- + m+mPoint 5
ATLAS
~
l
30 fb-1
atlfast
Physics
TDR
DC1
5 fb-1
FULL SIM
ATLAS
Modified
Point 5
(tan(b) = 6)
e+e- + m+m- - e+m- - m+e-
• Position of edge measured
with precision ~ 0.5%
(30 fb-1).
Dan Tovey
5
Freiburg, October 2004
Measurements With Squarks
•
•
•
•
Dilepton edge starting point for reconstruction of decay chain.
Make invariant mass combinations of leptons and jets.
Gives multiple constraints on combinations of four masses.
Sensitivity to individual sparticle masses.
~
qL
~
q c0 2
l
~
l
l
~
c0 1
lq edge
1% error
(100 fb-1)
1% error
(100 fb-1)
ATLAS
Dan Tovey
ATLAS
~
q c0 2
llq threshold
2% error
(100 fb-1)
TDR,
Point 5
TDR,
Point 5
ATLAS
6
~
c0 1
h
b
llq edge
TDR,
Point 5
~
qL
b
bbq edge
1% error
(100 fb-1) TDR,
Point 5
ATLAS
Freiburg, October 2004
Sbottom/Gluino Mass
• Following measurement of squark, slepton
and neutralino masses move up decay
chain and study alternative chains.
• One possibility: require b-tagged jet in
addition to dileptons.
• Give sensitivity to sbottom mass (actually
two peaks) and gluino mass.
~0 mass
• Problem with large error on input c
1
remains g reconstruct difference of gluino
and sbottom masses.
~
~
• Allows separation of b1 and b2 with 300 fb-1.
p
p
~g ~
b
b
Dan Tovey
~
c0 2
b
~
lR
l
Gjelsten et al., ATL-PHYS-2004-007
~
~0 )
m(g)-0.99m(c
1
= (500.0 ± 6.4) GeV
300 fb-1
ATLAS
SPS1a
~)
~
m(g)-m(b
1
= (103.3 ± 1.8) GeV
~
~
m(g)-m(b
2)
= (70.6 ± 2.6) GeV
ATLAS
300 fb-1
~0
c1
SPS1a
l
7
Freiburg, October 2004
RH Squark Mass
Gjelsten et al., ATL-PHYS-2004-007
• Right handed squarks difficult as rarely decay via ‘standard’ ~
c02 chain
~ gc
~0 q) > 99%.
– Typically BR (q
R
1
• Instead search for events with 2 hard jets and lots of ETmiss.
• Reconstruct mass using ‘stransverse mass’ (Allanach et al.):
mT22 =
min
c(1)
c(2)
miss
[max{mT2(pTj(1),qTc(1);mc),mT2(pTj(2),qTc(2);mc)}]
q
+q
=E
~
0
• Needs c 1 mass measurement as input.
• Also works for sleptons.
T
T
T
~
c0 1
q
ATLAS
ATLAS
30 fb-1
30 fb-1
Right
squark
SPS1a
~
qR
ATLAS
100 fb-1
SPS1a
SPS1a
Right
squark
Left slepton
Precision ~ 3%
Dan Tovey
8
Freiburg, October 2004
Heavy Gaugino Measurements
Polesello, SN-ATLAS-2004-041
• Also possible to identify dilepton edges from
decays of heavy gauginos.
• Requires high stats.
• Crucial input to reconstruction of MSSM
neutralino mass matrix (independent of
SUSY breaking scenario).
ATLAS
SPS1a
ATLAS
100 fb-1
Dan Tovey
ATLAS
100 fb-1
9
ATLAS
100 fb-1
SPS1a
Freiburg, October 2004
‘Model-Independent’ Masses
Allanach et al., ATL-PHYS-2002-005
Rome
• Combine measurements from edges
from different jet/lepton
combinations to obtain ‘modelindependent’ mass measurements.
~
c0
~
lR
1
ATLAS
Mass (GeV)
~c0
2
ATLAS
Mass (GeV)
ATLAS
Mass (GeV)
~
q
L
ATLAS
Mass (GeV)
Sparticle Expected precision (100 fb-1)
~
qL
 3%
~
c02
 6%
~
lR
 9%
~
c01
 12%
Dan Tovey
10
Freiburg, October 2004
Measuring Model Parameters
Rome
Polesello et al., ATL-PHYS-2004-008
• Alternative use for SUSY observables (invariant mass end-points,
thresholds etc.).
• Here assume mSUGRA/CMSSM model and perform global fit of model
parameters to observables
– So far mostly private codes but e.g. SFITTER, FITTINO now on the market;
– c.f. global EW fits at LEP, ZFITTER, TOPAZ0 etc.
Point
LHC Point 5
SPS1a
Parameter
m0
m1/2
tan(b)
A0
Dan Tovey
m0 m1/2 A0
100 300 300
100 250 -100
tan(b) sign(m)
2
+1
10
+1
Expected precision (300 fb-1)
 2%
 0.6%
 9%
 16%
11
Freiburg, October 2004
SUSY Dark Matter
Rome
• Can use parameter measurements
for many purposes, e.g. estimate
LSP Dark Matter properties (e.g.
for 300 fb-1, SPS1a)
– Wch2 = 0.1921  0.0053
– log10(scp/pb) = -8.17  0.04
Micromegas 1.1
(Belanger et al.)
+ ISASUGRA 7.69
Wc
Dan Tovey
h2
Polesello et al., ATL-PHYS-2004-008
Baer et al. hep-ph/0305191
LHC Point 5: >5s error (300 fb-1)
SPS1a: >5s
error (300 fb-1)
scp=10-11 pb
DarkSUSY 3.14.02
(Gondolo et al.)
+ ISASUGRA 7.69
scp=10-10 pb
scp
scp=10-9 pb
300 fb-1
300 fb-1
ATLAS
ATLAS
12
LEP 2
No REWSB
Freiburg, October 2004
SUSY Dark Matter
• SUSY (e.g. mSUGRA) parameter space strongly constrained by
cosmology (e.g. WMAP satellite) data. mSUGRA A0=0,
tan(b) = 10, m>0
Ellis et al. hep-ph/0303043
'Focus point'
region:
~
significant h
component to
LSP enhances
annihilation to
gauge bosons
Disfavoured by BR (b  sg) =
(3.2  0.5)  10-4 (CLEO, BELLE)
c~01
c~01
'Bulk' region: tchannel slepton
exchange - LSP
mostly Bino.
'Bread and
Butter' region for
LHC Expts.
DC1
Dan Tovey
~0
c
1
DC2
l
~
lR
t~1
t
t~1
g/Z/h
Slepton Coannihilation
region: LSP ~
pure Bino. Small
slepton-LSP
mass difference
makes
measurements
difficult.
l
Also 'rapid
annihilation funnel'
at Higgs pole at
0.094  W c h2  0.129
(WMAP)
high tan(b), stop
co-annihilation
region at large A0
13
Freiburg, October 2004
Coannihilation Signatures
• Small slepton-neutralino mass
difference gives soft leptons
Comune, ATL-COM-PHYS-2004-052
DC2
Rome
100 fb-1
– Low electron/muon/tau energy
thresholds crucial.
ATLAS
• Study point chosen within region:
– m0=70 GeV; m1/2=350 GeV; A0=0;
tanß=10 ; μ>0;
– Same model used for DC2 study.
• ETmiss>300 GeV
• 2 OSSF leptons
PT>10 GeV
• >1 jet with PT>150
GeV
• OSSF-OSOF
subtraction applied
Preliminary
~
~
• Decays of ~c02 to both lL and lR
kinematically allowed.
– Double dilepton invariant mass
edge structure;
– Edges expected at 57 / 101 GeV
100 fb-1
• Stau channels enhanced (tanb)
– Soft tau signatures;
– Edge expected at 79 GeV;
– Less clear due to poor tau visible
energy resolution.
Dan Tovey
Preliminary
14
ATLAS
• ETmiss>300 GeV
• 1 tau PT>40
GeV;1 tau PT<25
GeV
• >1 jet with
PT>100 GeV
• SS tau
subtraction
Freiburg, October 2004
Focus Point Models
Lari, ATL-COM-PHYS-2004-048
• Large m0  sfermions are heavy
• Most useful signatures from heavy neutralino decay
• Study point chosen within focus point region :
Rome
– m0=3000 GeV; m1/2=215 GeV; A0=0; tanß=10 ; μ>0
~0 → c
~0 ll
• Direct three-body decays c
n
1
~0 )-m(c
~0 )
~
• Edges give m(c
c 02 → ~
c01 ll
n
1
~0 → ~
c
c01 ll
3
ATLAS
Z0 → ll
ATLAS
30 fb-1
Preliminary
Preliminary
Dan Tovey
15
Freiburg, October 2004
SUSY Spin Measurement
Barr, ATL-PHYS-2004-017
• Q: How do we know that a SUSY signal is really due to SUSY?
– Other models (e.g. UED) can mimic SUSY mass spectrum
• A: Measure spin of new particles.
• One proposal (Barr) – use ‘standard’ two-body slepton decay chain
– charge asymmetry of lq pairs measures spin of ~c02
– relies on valence quark contribution to pdf of proton (C asymmetry)
– shape of dilepton invariant mass spectrum measures slepton spin
Spin-0
Measure
Angle
A
Spin-½

l  l
  
l l
Point 5
Point 5
ATLAS
150 fb -1
mlq
spin-0=flat
Polarise
Spin-½,
Spin-0
mostly wino
Dan Tovey
150 fb -1
ATLAS
Straight
line distn
(phase-space)
Spin-½,
mostly bino
16
Freiburg, October 2004
Little Higgs Models
DC2
Rome
• Solves hierarchy problem by cancelling loop corrections (top,
W/Z, Higgs loops) to the Higgs mass with new states.
• New states derived from extended gauge group rather than new
continuous symmetry (c.f. SUSY).
• ‘Littlest Higgs’ model contains ‘not too little, not too much, but
just enough’ extra gauge symmetry [ SU (2)1  U (1)1 ]  [ SU (2)2  U (1)2 ]:
– Electroweak singlet T quark (top loop) – mixes with top;
– New gauge bosons WH, AH, ZH (W/Z loops);
– New SU(2)L triplet scalars, including neutral, singly charged, doubly
charged f (Higgs loops).
• Requirement that these states protect Higgs from large
corrections limits their masses:
t
– T quark ~ 1 TeV;
– WH, AH, ZH ~ 1 TeV;
– f0, f+/-, f+/-+/- ~ 10 TeV.
Dan Tovey
17
Freiburg, October 2004
Littlest Higgs Model
Azuelos et al., SN-ATLAS-2004-038
• Searches for/measurements of new particles studied.
• For T quark single production assumed.
• Yukawa couplings governed by 3 parameters (mt, mT,
l1/l2) – top mass eigenstate is mixture of t and T:
l1 (iQhtr  fTL tr hh )  l2 f (TLTR )
†
•
1
2
MT
Decays:  (T  t h)   (T  tZ )   (T  bW ) 
2
32

Dan Tovey
 (T  tDC2
h)   (T  tZ ) 
Rome

l12
l12  l22
l12
l12  l22
18
Freiburg, October 2004
1
2
Heavy Gauge Bosons
DC2
Azuelos et al., SN-ATLAS-2004-038
Rome
• WH, ZH, AH arise
from [SU(2)  U(1)]2
symmetry
 2 mixing angles
(like qW): q for ZH,
q’ for AH
AH  e  e  reach for 300 fb1
Branching Ratio
Dan Tovey
19
Freiburg, October 2004
Z’, W’ studies
DC2
Rome
M. Schaefer
different models
full sim. in progress
O. Gaumer
full simulation
Dan Tovey
20
Freiburg, October 2004
Extra Dimensions
•
•
•
•
•
M-theory/Strings g compactified Extra Dimensions (EDs)
Q: Why is gravity weak compared to gauge fields (hierarchy)?
A: It isn’t, but gravity ‘leaks’ into EDs.
Possibility of Quantum Gravity effects at TeV scale colliders
Variety of ED models studied by ATLAS (a few examples follow):
SM
Large (>> TeV-1)
4-brane
– Only gravity propagates in the EDs, MeffPlanck~Mweak
– Signature: Direct or virtual production of Gravitons
TeV-1
– SM gauge fields also propagate in EDs
– Signature: 4D Kaluza-Klein excitations of gauge fields
SM
4-brane
Warped
– Warped metric with 1 ED
y = rc
– MeffPlanck~Mweak
– Signature: 4D KK excitations of Graviton (also Radion scalar)
Dan Tovey
21
y=0
Freiburg, October 2004
Large Extra Dimensions
Vacavant et al., SN-ATLAS-2001-005
• With d EDs of size R, observed Newton constant related to
fundamental scale of gravity MD:
DC2
-1
d
2+d
GN =8R MD
Rome
• Search for direct graviton production in jet(g) + ETmiss channel.
Gg g gG, qg g qG, qq g Gg
ATLAS
Single jet,
100 fb-1
Signal : graviton + 1 jet
production
Main background:
Jet + Z(W) [Z g nn, W g ln]
q/g
q/g
q/g
100 fb-1
ATLAS
G
q/g
MDmax (ET>1 TeV, 100 fb-1)
= 9.1, 7.0, 6.0 TeV
for d=2,3,4
Dan Tovey
22
Freiburg, October 2004
TeV-1 Scale ED
•
•
•
•
Usual 4D + small (TeV-1) EDs + large EDs
(>> TeV-1)
SM fermions on 3-brane, SM gauge bosons on
4D+small EDs, gravitons everywhere.
4D Kaluza-Klein excitations of SM gauge bosons
(here assume 1 small ED).
Polesello et al., SN-ATLAS-2003-036
• Masses of KK modes given by:
Mn2=(nMc)2+M02
for compactification scale Mc and SM mass M0
• Look for l+l- decays of g and Z0 KK modes.
• Also ln decays (mT) of W+/- KK modes.
• Also g KK modes recently studied (in progress).
ATLAS
100 fb-1
100 fb-1
ATLAS
• 5s reach for 100 fb-1 ~ 5.8 TeV (Z/g)
~ 6 TeV (W)
• For 300 fb-1 l+l- peak detected if
Mc < 13.5 TeV (95% CL).
Dan Tovey
23
Freiburg, October 2004
Warped Extra Dimensions
Allanach et al., ATL-PHYS-2002-031
• Search for gg(qq) g G(1)
g e+e-. Study using test
model with k/MPl=0.01
(narrow resonance).
• Signal seen for mass in
range [0.5,2.08] TeV for
k/MPl=0.01.
• Measure spin
(distinguish from Z’)
using polar angle
distribution of e+e-.
• Measure shape with
likelihood technique.
• Can distinguish spin 2
vs. spin 1 at 90% CL for
mass up to 1.72 TeV.
Dan Tovey
DC2
m1 = 1.5 TeV
100 fb-1
Rome
100 fb-1
ATLAS
Experimental
resolution
ATLAS
m1 = 1.5 TeV 100 fb-1
100 fb-1
ATLAS
24
ATLAS
Freiburg, October 2004
Black Hole Signatures
• In large ED (ADD) scenario, when
impact parameter smaller than
Schwartzschild radius Black Hole
produced with potentially large x-sec
(~100 pb).
• Decays democratically through
spherical Black Body radiation of SM
states – Boltzmann energy distribution.
w/o pile-up
ATLAS
Tanaka et al., ATL-PHYS-2003-037
M P  6 TeV
Rome
- select spherical events
- Reconstruct MBH for each event
- Reconstruct MP from ds/dMBH
- Reconstruct TH from distribution of MBH
- Deduce n from TH, MBH and MP
• Discovery potential
Mp=1TeV, n=2, MBH = 6.1TeV
Dan Tovey
25
– Mp < ~4 TeV  < ~ 1 day
– Mp < ~6 TeV  < ~ 1 year
Freiburg, October 2004
Other Topics for Rome
• Exotics group also studying variety of other models using
full-sim for Rome:
– Doubly charge Higgs
– Sequential heavy leptons
– Excited leptons
Dan Tovey
26
Freiburg, October 2004
Summary
• Much work on Beyond the Standard Model Physics being carried out.
• Lots of input from both theorists (new ideas) and experimentalists
(new techniques).
• Exotics and SUSY WGs contributing fully to Data Challenges
– Validating software
– Performing new studies reliant on detector performance
• Plan for extensive set of full-sim studies for Rome.
• Big effort ramping up now to understand how to exploit first data in
timely fashion
–
–
–
–
Calibrations
Background rejection
Background estimation
Tools
• Lots of scope for new people/groups to get involved.
Dan Tovey
27
Freiburg, October 2004
BACK-UP SLIDES
Dan Tovey
28
Freiburg, October 2004
Inclusive Searches
•
•
•
•
Use 'golden' Jets + n leptons + ETmiss discovery channel.
Map statistical discovery reach in mSUGRA m0-m1/2 parameter space.
Sensitivity only weakly dependent on A0, tan(b) and sign(m).
Syst.+ stat. reach harder to assess: focus of current & future work.
5s
5s
ATLAS
Dan Tovey
ATLAS
29
Freiburg, October 2004
SUSY Mass Scale
• First measured SUSY parameter
likely to be mass scale:
Jets + ETmiss + 0 leptons
– Defined as weighted mean of
masses of initial sparticles.
ATLAS
• Calculate distribution of 'effective
mass' variable defined as scalar
sum of masses of all jets (or four
hardest) and ETmiss:
Meff=S|pTi| + ETmiss.
• Distribution peaked at ~ twice
SUSY mass scale for signal events.
• Pseudo 'model-independent'
measurement.
• Typical measurement error
(syst+stat) ~10% for mSUGRA
models for 10 fb-1.
Dan Tovey
30
10 fb-1
ATLAS
10 fb-1
Freiburg, October 2004
Exclusive Studies
• With more data will attempt to measure weak scale SUSY parameters
(masses etc.) using exclusive channels.
• Different philosophy to TeV Run II (better S/B, longer decay chains) g
aim to use model-independent measures.
p
p
~
q
~g
q
~
c0 2
q
~
lR
l
~
c0 1
l
• Two neutral LSPs escape from each event
– Impossible to measure mass of each sparticle using one channel alone
• Use kinematic end-points to measure combinations of masses.
• Old technique used many times before (n mass from b decay
spectrum, W (transverse) mass in Wgln).
• Difference here is we don't know mass of neutral final state particles.
Dan Tovey
31
Freiburg, October 2004
Mass Relation Method
Nojiri et al., ATL-PHYS-2003-039
• Hot off the press: new idea for reconstructing SUSY masses!
• ‘Impossible to measure mass of each sparticle using one channel
alone’ (Page 8).
– Should have added caveat: Only if done event-by-event!
• Remove ambiguities by combining different events analytically g
‘mass relation method’ (Nojiri et al.).
• Also allows all events to be used, not just those passing hard cuts
(useful if background small, buts stats limited – e.g. high scale SUSY).
ATLAS
Preliminary
Dan Tovey
ATLAS
SPS1a
32
Freiburg, October 2004
Chargino Mass Measurement
• Mass of lightest chargino very
difficult to measure as does not
participate in standard dilepton
SUSY decay chain.
• Decay process via n+slepton
gives too many extra degrees
of freedom - concentrate
~+ g W c~0 .
instead on decay c
1
1
• Require dilepton ~
c02 decay
chain on other ‘leg’ of event
and use kinematics to calculate
chargino mass analytically.
• Using sideband subtraction
technique obtain clear peak at
true chargino mass (218 GeV).
• ~ 3 s significance for 100 fb-1.
Dan Tovey
~0
c
1
~
c+1
W
q q q
Nojiri et al., ATL-PHYS-2003-040
q
~
q ~
g
p
~0
~
c
~
0
1
c
p
2
lR
~
g ~
q q
q
l
l
PRELIMINARY
Modified
LHCC Point 5:
m0=100 GeV;
m1/2=300 GeV;
A0=300 GeV;
tanß=6 ; μ>0
100 fb-1
33
Freiburg, October 2004
Coannihilation Models
• Small slepton-neutralino mass difference gives soft leptons from
decay
– Low electron/muon/tau energy thresholds crucial.
p
p
~
q
~g
q
~
c0 2
q
~
lR
l
~0
c1
l
• At high tan(b) stau decay channel dominates.
– Need to be able to ID soft taus (good jet rejection).
• Study started within ATLAS examining signatures of these models.
• Study point chosen within coannihilation region :
– m0=70 GeV; m1/2=350 GeV; A0=0; tanß=10 ; μ>0
• Same model to be used for DC2 SUSY study.
Dan Tovey
34
Freiburg, October 2004
Physics Commissioning
(See also talk during Commissioning Workshop earlier in week)
• Preparations needed to ensure efficient/reliable searches
for/measurements of SUSY particles in timely manner:
–
–
–
–
Initial calibrations (energy scales, resolutions, efficiencies etc.);
Minimisation of poorly estimated SM backgrounds;
Estimation of remaining SM backgrounds;
Development of useful tools.
• Many issues will be common with other WG, esp:
–
–
–
–
Standard Model (W (gln) + n jet, Z(gll) + n jet) from Z(gl+l-) + n jet);
Top (full reconstruction of semi-leptonic ttbar events);
Higgs (Estimation of high ETmiss backgrounds)
Jet/ETmiss (Estimation of fake ETmiss QCD backgrounds, jet energy scale
etc.);
– Combined Performance groups (calibration of energy scales, resolutions
and efficiencies).
• Should work together to develop common tools and analysis strategies
wherever possible …
Dan Tovey
35
Freiburg, October 2004
Little Higgs
Introduce
scalar fields
gauge symmetry
f  f   f e it  ( x )
SU(5)
global
SU (5)  SO (5)
v ~ f ~ TeV
local subgroup
[ SU (2)1  U (1)1 ]  [ SU (2)2  U (1)2 ]
 [ SU (2)L  U (1)Y ]
Littlest Higgs model
broken
massive gauge
vector bosons
Massless Goldstone
bosons
4
14 Goldstone bosons
10
h, f
Dan Tovey
broken
( Higgs mechanism)
36
Z H , g H ,WH
Higgs is a
gauge boson !
Freiburg, October 2004
Littlest Higgs Model
In SU (2) L  U (1)Y basis,
(2t  1)Y / 2
Q  t3 
X
10
h
Y
2
WH , Z H , g H : ~ 1 TeV
T : ~ 1 TeV
21/ 2
f
31
Y

  eaten  4 heavy bosons: Z H , g H , WH
30 

  complex higgs doublet, massless
21/ 2 
triggers EW symm. breaking
h†
vev for h
f 
†
 mass to Z, W, h massless
  complex triplet
acquires mass from one-loop gauge interactions
3 1 
f  , f  , f 0 : ~ 10 TeV
1-loop gauge interactions:
t
To cancel the top loop,
introduce SU(2)L singlet quark TL,
and TR
l1 (iQhtr  fTL tr hh† )  l2 f (TLTR )
Dan Tovey
37
Freiburg, October 2004
Higgs-Gauge Boson Couplings
Azuelos et al., SN-ATLAS-2004-038
• Measurement of ZHZh and WHWh couplings needed to test model
Z H  Zh 
Z H  Zh  qq gg
bb
WH  Wh  qq gg
m Z H  2 TeV
WH  Wh  n bb
WH  Wh  n bb
B-tagging at
high energy
needed
high energy
Dan Tovey
38
Freiburg, October 2004
Heavy Leptons
• Extra heavy leptons
present in many
extended gauge
models.
• Study l+l-+4j channel.
• Backgrounds from
ttbar, WZ, WW, ZZ.
• Also 6 lepton channel.
Experimental considerations:
- high energy leptons, jets
Systematics:
- large NLO corrections
Alexa et al., ATL-PHYS-2003-014
M L  500 GeV
M Z '  700 GeV
conclusion:
ATLAS can discover
sequential charged
heavy leptons up to
ML = 0.9 / 1.0 TeV
(low/high luminosity)
Dan Tovey
DC2
39
Rome
Freiburg, October 2004
Excited Quarks
1 * mn 
t
Y

a
qRs  g s f sGmn
 g f Wmn  g ' f ' Bmn  qL  h.c.
2
2
2


take as reference :   m*, f s  f  f '  1
L
O. Çakir, C. Leroy, R. Mehdiyev,
ATL-PHYS-2002-014
q g  q*  q g
ATL-PHYS-99-002
q g  q*  q g
ATL-PHYS-99-024
Also : q*  qZ ; q*  q 'W
Dan Tovey
DC2
40
Rome
Freiburg, October 2004
Excited Leptons
e*  e Z  e jj
g*2
contact interaction : LC 
Jm J m
2
2
Experimental considerations:
- high energy e, g
- Z  jj, W  jj
DC2
Rome
L = 300 fb-1,  = 6 TeV
pp  ee*  e e g
Dan Tovey
41
Freiburg, October 2004
Black Hole Production
• Theoretical Uncertainties
Rome
– production cross section
– disintegration
• emission of gravitational radiation (balding phase)
• main phase ? = Hawking radiation, or evaporation
– spin-down phase: loss of angular momentum
– Schwarzschild phase: emission of particles
» quantum numbers conserved?
• Planck phase: impossible to calculate
–  CHARYBDIS generator: time evolution, grey-body factors, Planck phase
CM Harris, P. Richardson and BR Webber, JHEP 0308 (2003) 033 (hep-ph/0307305)
• Characteristics
– temperature: depends on the mass
n  1  MP n  2 
TH ( MP , n, MBH )  MP


4   MBH 8   n2 3  
– black body radiation: emission of particles
1
n 1

n1
4 RS( n )
• high multiplicity
• “democratic” emission
• spherical distribution
Dan Tovey
42
Freiburg, October 2004