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Toward New Physics

At the LHC

Lecture 4: New Physics

April 3, 2008

Joseph R. Incandela

University of California, Santa Barbara

21st Spring School on Particles and Fields

The Institute of Physics, National Chiao-Tung University,

HsinChu, Taiwan

The experimental program of the Large Hadron Collider at CERN

Acknowledgements

• I thank the following people (in no preferred order) for their slides:

• Rick Cavanaugh, Daniel Froidevaux, Dan Green, Steinar Stapnes, Jörg

Wenninger, Sally Dawson, Ian Hinchliffe, Karl Jacobs, Oliver Buchmuller, Ian

Low, Albert De Roeck, Andy Parker, Roberto Tenchini, Guenther Dissertori,

Jorgen D‟Hondt,…

• I thank the following people for discussions and special info

• Peter Jenni, Henry Frisch, Paris Sphicas, Claudio Campagnari, Chris Quigg,

Philip Schuster, Natalia Toro, …and

• … many others from UA1, UA2, CDF, D0, OPAL, ALEPH, CMS, ATLAS…

LHC Lectures NCTU, Hsin Chu, Taiwan, March 31-April 3, 2008 J.R.Incandela

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Recall

There‟s currently an interesting set of

circumstances in two “fundamental” areas of

Physics*:

• Experimental Particle Physics

• Many precise results with no substantial discrepancies with

the Standard Model (SM)

• Experimental Astrophysics and Cosmology

• Abundant (literally) evidence for new physics

*next few slides inspired byIan Low (UC Irvine)


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Possible Implications

• The division is itself a major clue and constrains theory

• Viable models (that evade constraints of precision measurements) often have common features

The common structure can produce

similar phenomenology

We may see something that is not so

easy to interpret


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7/79 77

Nevertheless, the case for

Supersymmetry (SUSY) is compelling

And so we have to consider it seriously


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• Extension of known space-time symmetries• 10 generators of Poincare group:

• Lj, Kj, Pm for rotations, boosts, translations

• SUSY fermionic operators Qa

• Arises naturally in String theory

• Is the maximal possible extension of the Poincare group

Qa acting on any state produces a new state having the same

quantum numbers - except spin which is shifted by ½

• Fermions Bosons are interchanged under group transformation.

• Initial state a SM particle final state its superpartner

• No SM particle is the super-partner of another SM particle

• Supersymmetry is broken

• Mass degenerate superpartners would have been discovered long

ago there must be symmetry breaking contributions to the

masses which are large and positive.

• Once broken…Superpartner mass scale is unconstrained but there is

strong motivation for the weak scale

Supersymmetry*

* J. Feng hep-ph/0405215v2


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SUSY and the weak scale

• Higgs mass:

• correction has quadratic divergence!

• a cut-off scale – e.g. Planck scale

• Superpartners fix this:• Need same coupling

• Need superpartners at the weak scale

• Otherwise the logarithmic term becomes too large, which would require

more fine-tuning.

• Known as “soft” SUSY-breaking terms (others are possible)

Cancellation


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SUSY Spectrum of Neutrals*

• Need 2 Higgs doublets• Avoids triangle anomalies (divergent process involving a fermion

triangle loop with gauge bosons at the vertices)

• Elegant choice Hu and Hd

• They give mass to up- and down-like fermions separately

• Helps evade large Flavor Changing Neutral Currents (FCNC)

• Neutral Spectrum:

• Spin 0 sneutrinos, spin 3/2 gravitino, spin ½ Bino, Wino, and Higgsinos

Mass parameters


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• The 4 spin ½ neutral SUSY partners only differ in their

electroweak quantum nos.

• With SUSY broken, they are free to mix to form mass eigenstates

• These are the neutralinos k

with k=1,2,3,4

• These fermions are Majorana (particle=antiparticle)

• Beyond neutrals - spectrum as expected

• Fermion (boson) superpartner for each SM boson (fermion)

Spectrum (cont.)


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• Superpartners solve some and create other problems

• Gauge hierarchy problem eliminated

• But now protons decay too rapidly

• Superpartners mediate both L and B number violation

• Need a new symmetry: R parity conservation

R = (-1)3(B-L)+2S where B,L,S=Baryon #, Lepton #, and Spin

R= +1 (-1) for all SM particles (SUSY partners)

• Consequence: Lightest SUSY Particle (LSP) stable

• Cannot decay into SM particles

• And … impact of SUSY spectrum on SM particles is diminished

R-Parity


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• What is the LSP?

• Must understand how SUSY is broken

• specifies soft SUSY breaking terms & so the mass spectrum

• SUSY breaking is a vast and technical subject!

• Popular models assume a hidden sector is involved:

• Sounds ad-hoc, but there is a precedent: Electroweak Symmetry

Breaking (EWSB)

SUSY breaking (SB)


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• EWSB divides SM interactions into 3 sectors

1. “EWSB”: involving only the Higgs

2. “Observable”: gauge bosons, quarks and leptons

3. “Mediation”: involving the interactions between sectors

1 and 2 (i.e. Yukawa interactions)

• Higgs obtains non-zero vacuum expectation value (vev) and

this occurrence is communicated to the SM fermions via some

unknown mediator.

• Same concept applies to SUSY breaking

1. “SUSY-Breaking”: Fields Z not in SM

2. “Observable”: SM particles and their superpartners

3. “Mediation”: all interactions between SUSY-breaking

fields Z and observable fields

Mediation


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SUSY Breaking

• Simplest cases, one field Z has non-zero vev F

• Gravitino acquires mass m3/2 = F/(3 M*)

• M* = (8GN)-½ 2.4 x 1018 GeV (reduced Planck mass)

• Mediation sector terms for Z interacting with

superpartners become mass terms when Z F

f, =superpartners of SM fermions and gauge bosons ~


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• Supergravity Models

• Mediating interactions are gravitational: Mm ~ M*

• m3/2, mḟ, m ~ F/ M*

• F ~ (Mweak M*) 1010 GeV

High Scale SUSY-Breaking

Any superpartner OR the Gravitino could be the LSP

• Gauge-Mediated (GMSB)

• Mediating fields are gauge fields: Mm M*

• m3/2 = F/(M*3) mḟ, m ~ F/ Mm

• F ~ (Mweak Mm) 1010 GeV

Low-scale SUSY-breaking

Gravitino = LSP

Models


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• Spectrum depends on how SUSY breaks

• Infinite possibilities

• Can narrow the field with several assumptions

• Assume weak-scale SUSY derives from something more

fundamental (e.g. Grand Unification or String theories)

• Assume the fundamental theory is highly structured

• Why highly structured?

• Partly driven by aesthetics (simplicity)

• Also because the gauge couplings unify

• Occurs in SUSY models that are run up to higher energy via

the renormalization group equations

SUSY Models


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Gauge Coupling Unification


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• Thus, the idea is the following:

• The many (>100) parameters of weak-scale SUSY

should be derived from a minimal set of parameters at

the unification scale.

• mSUGRA: the “canonical” model

• 5 main parameters

• mo , m1/2 , Ao , tan(b), and sign(m)

• mo , m1/2 are universal scalar and fermion masses

• Like the couplings, one assumes that the spectra of

fundamental particles derives from fundamental masses

• m3/2 is a 6th free parameter

• Gravitino - could be LSP but in most of the literature it is

assumed to be very heavy and ignored.

Minimal Supergravity (mSUGRA)


21/79 An example of renormalization group evolution

of universal SUSY masses in mSUGRA

• Generally valid features:

• Evolving from GUT scale

• Gauge couplings increase SUSY

masses

• Yukawa couplings decrease them

• Thus• Colored particles are heavy Not

LSP candidates

• Bino is the lightest gaugino

• Right-handed slepton the lightest

scalars (specifically stau ÌR)

• (mHu)2 is driven negative by the

large top Yukawa coupling!

What is this about?


22/79 Minimization of the EWK potential for

Electroweak Symmetry Breaking

• At tree level EWSB requires

• True for all but lowest

values of tan(b) (which are

disfavored anyway)

• Can only be satisfied if

(mHu)2 <0

• No other mass parameters

are so significantly affected

by the large top Yukawa

coupling

A natural explanation of

why SU(2) is the only SM

symmetry that is broken

A large top mass then has a significant role in SM phenomenology through SUSY


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• Minimal Case of 2 doublets:

• After W,Z masses, 5 remaining d.o.f.

• 5 physical Higgs bosons ho, Ho, Ao, H

• Scalar potential has one free parameter

• Masses are expressed in terms of mA and tanb

tanb = v2/v1 and v12+ v2

2 = v2

Where v1 (v2) are the vev‟s for the Hd (Hu)

• Large radiative corrections (at one-loop)

• Mh2 < MZ

2 + (3GF/(21/2p2)) Mt4 ln(1+m2/Mt

2)

• Mh 130 GeV

150 GeV (if there are also Higgs singlet(s))

• Important feature• Couplings to vector bosons now shared

ghoVV

2 + gHoVV2 = gHVV

2 (SM)

Minimal SUSY Higgs Sector


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Back to the LSP

• Scan parameter space

for LSP possibilities

• One slice through

mSUGRA shown here

• The LSP in mSUGRA

• Lightest neutralino c1

or the RH stau ÌR

• Many other models exist

• But mSUGRA contains a very wide variety of

phenomenological possibilities and LSP candidates

Useful for studying a broad array of signatures. This is

what is done in CMS.

Dark Matter

Another motive for

R-Parity-Conserving SUSY


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R. Kolb at SUSY07 Karlsruhe


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• Matter is only 5% of the energy in the universe.

• Cosmology-Astrophysics evidence for physics beyond the

Standard Model (BSM) is overwhelming

• Relic Density for non-baryonic dark matter:

• 0.094 < DM h2 < 0.129 (95% CL), h = 0.71 (km/s)/Mpc

(Hubble expansion)

• Weak scale SUSY with R-Parity conservation is

perhaps the best-motivated framework

• Provides a natural dark matter candidate (neutralino)

• Leads to remarkable gauge coupling unification

• Can provide an explanation for why SU(2) is broken

• Solves the gauge hierarchy problem

The Dark Side


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Thermal Relic Density

• As universe expands

• Interactions/annihilations

cease at a time that

depends on annihilation

cross section sA times

mean velocity v

• Freeze out condition:

• Neq ~ sAv~T2/M*

• Weakly Interacting Massive

Particles (WIMPs)

• Mass and annihilation

xsec set by weak scale

m2 ~ sA v-1 ~ Mwk2

• Thus a 300 GeV WIMP

freezes out at T ~ 10 GeV

and t~10-8 s

• The freeze-out density is:

~ 10-10 GeV-2/ sA v

• Typical weak xsec:

sA v~a2/Mwk2~10-9 GeV-2

h2 ~0.1


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• Though SUSY looks very compelling, theorists

have proposed many alternatives and we do not

know which if any is the right one …

• Strong dynamics

• Grand Unified theories

• Little Higgs

• String-theory motivated models

• ADD Large extra dimension

• Randall Sundrum warped extra dimension

• More on this later…

Beyond SUSY

Before presenting results of all of the

studies done by ATLAS and CMS…

The experimentalist‟s perspective


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prologue

• “Inputs, from LEP and from HERA, beautifully merge into the tools

that have been developed to describe proton-antiproton collisions at

the Tevatron, where the agreement between theoretical predictions

and data confirms that the key assumptions of the overall approach

are robust. ….”*

*Michelangelo Mangano:

Understanding the Standard Model, as a bridge to the discovery of

new phenomena at the LHC http://arxiv.org/abs/0802.0026v2

I draw upon the contents of this paper at various places in this talk.

• We come to the LHC from a variety of previous accelerator

complexes (LEP, HERA, SLAC, Tevatron…) and non-acclerator

experiments. This is a good thing, the job will take all of our

collective effort and experience …

http://arxiv.org/abs/0802.0026v2


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Past versus future discoveries• W & Z

• Masses and production rates were predicted

• Signals stood out “like being hit on the head with a hammer”

• Interpretation was unambiguous

• Top

• Signal was a bit harder to dig out (initially a counting experiment) and

less straightforward to interpret but…

• We knew it had to be “somewhere”

• Production and decay properties were predicted

• Higgs • Like top – for a given mass, we know its production and decay

properties in the SM and alternative BSMs. For some masses, counting

experiments may be the first sign.

• Or maybe like W & Z –the signal could appear as a striking mass peak

• New Physics (NP)

• Don‟t know what to expect. Theory provides examples, some are

compelling, none are guaranteed ...

Past

Futu

re


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BSM Billboard


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BSM Signatures

• A few thoughts …

• Model builders provide ideas for

unexpected signatures

• Very uncertain that any of these

models will be seen, but there are

benefits

• We prepare more broadly

• We are motivated to look at generic

things from a different perspective

• e.g. very boosted top quarks,

very high ET leptons,

triggering on jets when there‟s

no beam!

• The number and variety of

theories are indicative of

something else…

• What is really needed, is data.


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Our job description

• Efficiently acquire all interesting data and understand it in detail, as it

unfolds with increasing luminosity

• Understand the SM to the extent our data and existing MC allow (with

likely development and tuning of the latter due to the former)

• And then to see what is there that we cannot explain

• Not be biased by any particular models

• Be like Faraday. Listen to theorists but do not be too influenced. Observe

nature as purely as possible with methods that are continually refined by

experience.

• “If we see something odd in a given final state, it is not by appealing to, or

freshly concocting, a new physics model that gives rise to precisely this

anomaly that makes the signal more likely or more credible. The process

of discovery … should be based solely on the careful examination of

whether indeed this signal violates the SM expectation.” M.L.Mangano

• “Our analyses should be designed “to provide the extraordinary

evidence that is needed to back up an extraordinary claim”


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Good things come early

So far, hadron colliders have an unbroken streak of discovery opportunities

Low mass SUSY or some other source of Dark Matter could appear early


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SUSY Signatures• Different topologies for new

physics will overlap different SM

processes. Examples

• Jets + MET (but no leptons)

• Backgrounds: QCD,(tt, Z+Jets, tW)

• Jets + MET+2 OS leptons

• Background: mainly tt

• Different classes of observations

require different levels of scrutiny

• A mass peak or edge is self-

calibrating and unambiguous but

• “… almost certainly pass through a

period where the signal is marginal.”

• Anomalous kinematics are more

tricky but can be a smoking gun

• A counting experiment requires the

most effort to be fully convincing


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SUSY Signatures• Different topologies for new

physics will overlap different SM

processes. Examples

• Jets + MET (but no leptons)

• Backgrounds: QCD,(tt, Z+Jets, tW)

• Jets + MET+2 OS leptons

• Background: mainly tt

• Different classes of observations

require different levels of scrutiny

• A mass peak or edge is self-

calibrating and unambiguous but

• “… almost certainly pass through a

period where the signal is marginal.”

• Anomalous kinematics are more

tricky but can be a smoking gun

• A counting experiment requires the

most effort to be fully convincing


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SM at 10-14 TeV

• A new window on Nature

• We „ll see portions of the SM

that have never been seen.

• A lot of it will look familiar but

will be ornamented with jets to

a degree that we have not

previously encounteredQCD Jets


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SM at 10-14 TeV

• Low initial luminosity

• Study Min Bias

• Narrow down the current large

range of extrapolations of PDFs,

dN/dh etc

• Study Jets

• Initial optimization of jet algorithms

on real data for resolution, scale,

lepton and g fakes, etc.

• Then more complex final states

• Also calibrate with known objects

• Study candles for leptons and photons

• o,, initially to understand detector,

tracking, leptons & other objects

• Extend to W or Z leptons

• Compare to MC V+Jets

• Extend into tt core region and then

• Deal with tails…

QCD Jets


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“The LHC is a very Jetty place”*


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Life at low x in a pp collider

• LHC ≠ Tevatron

• Small momentum fractions x

in many key searches:

• large phase space for gluon

emission

• Consider tt:

• For a jet threshold of ~15 GeV,

essentially all tt events will

have 1 or more additional jets

• Consider V+jets

• Ratio of LHC to Tevatron

production cross sections for

W/Z + n jets becomes huge as

n increases

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

0 2 4 6

W+jets

Z+jets


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V+jets a bridge between data and theory• Theory has (generally) kept pace

• W+jets a key background for top

discovery. Estimated with data+MC

• Recent CDF results versus theory:

• Top Left : pTjet for Z+ 1j, Z + 2j

• Bottom: W+n jets

• Very good agreement at NLO

• MEPS matching routines – also

agree up to a constant k factor


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W+Jets: Jet ET spectra at LHC

• Studies in data are greatly facilitated by ratios

• [Z+(n+1)jets] / [Z+n jets]

• [W+n jets] / [Z+ n jets]

• Many systematics cancel at least partially

Projected ET

spectra of nth jet

(n=1,2,3,4) in

W+ n jet events at

the LHC using

various MEPS

MC and compared

to Alpgen

With one exception

all are within 50%

http://arxiv.org/abs/0802.0026v2


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tt at 14 TeV• Next we have to deal with tt

• The additional jets complicate

reconstruction/isolation of top.

• Top is not like W or Z

• “Top is not a candle, it‟s more like a

candelabra”

– Ken Bloom (U. Nebraska)

• Once we understand the control

regions: W/Z + n jets for low n, and

QCD fakes, we can begin to tackle

the core regions of tt.

• Then, have to understand the tails

• If there is a substantial BSM signal

overlapping any region of top, this

will be a difficult job and we will likely

have to rely even more on MC than

we did for V+jets

QCD Jets


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Also study tt by n jets


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The Devil will be in De Tails


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New Physics (NP)

• New physics will also occupy some

part(s) of this space

• Leptons for top are not different

than leptons for SUSY

• Work done in SM groups can be

directly translatable to NP

searches

• Event selection should reflect both

the need to study control regions

and the commonality of topologies

• Inclusivity of Triggers, Skims to allow

• Data driven QCD bkgd estimates

• Fakes estimates, cross-checks

• Common event selections will

facilitate comparisons

• More people study and help to

understand a given sample

QCD Jets


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SM processes we can‟t initially isolate: single top

• Accounted as backgrounds even before we can show they are there

• They are thus not critical to very early searches but will become very

useful as data accumulates.

• Single top

• Window to new physics:

• t‟, W‟, FCNC, SUSY

Access to top properties

• Also Dibosons

• t channel 9.9% @10fb-1

• W-associated ~20% @ 10 fb-1

• S-channel 36% @10fb-1

OK now to the studies…

And what new physics might look like


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New Physics Searches with CMS & ATLAS

• Sources: Physics Technical Design Report Vol. II• J. Phys. G. Nucl. Part. Phys. 34 (2007) 995-1579

• General Focus: low luminosity (2 x 1033) operation and integrated luminosities up to 30-60 fb-1

• Also considered very early data from a few pb-1 to a few fb-1

• Will draw on this work for this talk

• Can‟t cover it all (fortunately for you) not an expert all areas

• Highlight areas where new physics could reveal itself early

• CMS now preparing for really early data: 10 pb-1 -100 pb-1

• Many new studies are underway and some completed. See 2008 results:

• http://cms-physics.web.cern.ch/cms-physics/physics-home.htm

• ATLAS results shown here can be found at• https://twiki.cern.ch/twiki/bin/view/Atlas/AtlasPhysics

• 1000‟s of pages of documented studies

http://cms-physics.web.cern.ch/cms-physics/physics-home.htm







https://twiki.cern.ch/twiki/bin/view/Atlas/AtlasPhysics


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Spectacular LHC Events Soon to Come!


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*LM9

*LM8

CMS SUSY Benchmark Points (PTDR)

• Selection of 13

Points

• Low mass

LM1LM9

• High mass

HM1HM4

• Important: different

topologies/decay

modes, i.e. on

different signatures

• LM1,2,6,9 are also

close to WMAP

benchmarks


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Signature based analyses

• A Variety of inclusive analyses @ a specific

benchmark points then extended to the m1/2-mo plane

using FAMOS (CMS fast detector simulation)

• MET + jets @ LM1: MET>200

• Muons + MET + jets @ LM1: MET>130

• Same sign di-muons @ LM1: MET>200

• Opposite sign dileptons @ LM1:MET>200

• Di-taus @ LM2 : decays 95% to tt: MET>150

• Inclusive analysis with Higgs @LM5:MET>200

• Inclusive Zo @LM4:MET>230

• Inclusive top @ LM1: Top plus leptons: MET>150

c02

~ ~


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LM1: MET and 3 jets

• Cleanup instrumental

bkds, halo, cosmics, etc.

• E.g. require

• primary vertex

• Total EM fraction

Fem>0.175 • Fem = ET weighted EM

fraction in |h|<3

• Event charged

fraction Fch>0.1• Fch = PT of charged

tracks associated to

jets over calorimeter

jet ET in |h|<1.7


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MET in QCD events

• MET in QCD multijet

events tends to be along

leading or 2nd leading jet

directions

• SUSY populates a

distinct region

MET in QCD multijet events


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QCD MET from data


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Calibrate ZnØ + jets with Z mm +jets

Selected Zmm + 2jets with PT(Z) > 200Muons included

Selected ZnØ+ 2jets

Concern:

Model the ZnØ

background using

Z mm is great but

takes a lot of data

to get enough

dimuon events.

Couple alternatives

recently considered

Selected Zmm + 2jets with PT(Z) > 200Muons excluded


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Using W+jets

Yes !


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Using g + jets!

Eg in g + jets

EZ in Z + jets

Z just a massive g

But you don‟t pay the

branching ratio penalty

BR(Z mm) ~ 3%


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Jets + Missing ET

METLM1

Low mass SUSY


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Final event counts

• Final Cuts on ET of j1,j2,HT > 180,110,500 GeV

• Global signal efficiency 13%, S/B~26


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Inclusive SUSY searches

• Low-mass SUSY (Msp~500GeV) accessible with O(100 pb-1) Dt to discovery determined by:• Time to understand detector performance: MET tails, jet performance &

energy scale, lepton id

• Time to collect control samples -- e.g. g+jets, W+jets, Z+jets, WW, top..


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HM1

• Prior to data, backgrounds are not really known….

• More of a relevant issue for High Mass (HM) points


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Control Region :

Meff < 100 GeV

Inclusive MET + Jets + 1 lepton

Meff > 100 GeV

ATLAS

1 fb-1

• Add lepton clean trigger• Important during early running!

• Typical Characteristics:

• Single Isolated lepton• Low pT ~ 20-30 GeV

• 3 or 4 jets:• Hard leading (& NL) Jets

• Large MET• Typically > 100 GeV

• Cuts on D(jets, MET)

• Large Meff

• Main remaining backgrounds

• ttbar, W/Z+n-Jets Signal Region :

Meff > 100 GeV


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• Add 1 Same Flavor Lepton• Even cleaner

• Little to no QCD

• Typical Selection Strategy• Several, high pT Jets

• Large MET

• Strong lepton isolation cuts

• Main backgrounds• tt

• Double boson• 2 OS SF : W+W-, WZ, ZZ

• 2 SS SF : W+W+, W-W-

~unique to LHC

• Double partons not yet studied• W “+” W, W “+” Z, Z “+” Z

Inclusive MET + Jets + 2 leptons

p

p

m

mn

W m

,Zg

mn

d

u

u

u

u

d

W

d

d

W W


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Inclusive MET + Jets + 2 leptons

2 OS SF Leptons

2 SS SF Leptons

L = 1 fb-1

L = 1 fb-1


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SUSY signals (cascades)

0

2c

g~

q~

q q

0

2c

0hM(bb)

Can be

discovery

channel

for the

Higgs

1 fb-1

miss

TE0

1c miss

TE0

1c

h

b

0

2cb


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CMSSM:

Phys. Lett. B, 657/1-3 (2007)Preferred region @ 95%CL:

Discoverable with just 6 pb-1

Excludable with less than 1 fb-1!

Expected CMSSM Discovery Reach

• As a function of integrated luminosity

• For different discovery channels (1 fb-1) SN-ATLAS-2002-020

CMS Preliminary

Expected Tevatron Reach

ATLAS Similar

CMSSM:

without systematics

1 fb-1

ATLASPreliminary

What we see may be difficult to interpret

CMS

Preliminary

CMS AN 2006/008

Datta, Matchev, Kong

Phys.Rev. D72 (2005) 096006

• Minimal Universal Extra Dimensions• 1 Extra compact dimension: R

• Everything propagates in Bulk

• KK tower of “SM-like” states• evenly separated

• nearly degenerate

• Signatures like low mass SUSY!• Many Jets

• Large MET (KK parity stable LKP)

• Leptons• With OS dilepton mass edges

• High cross-section• Early Physics Potential

• Current constraints:• R-1 > 600 Gev (for mH >115 GeV)

q

l (near)

l (far)

ATLAS

Prel.

Gauge Mediated Breaking of SUSY

• SUSY broken at lower scale by Gauge Bosons

• Couple to “messengers” from hidden sector at

some high energy scale Fo

• Gravitino becomes LSP

• Neutralino can be NLSP

• Distinctive Signature

• Large MET

• Large Meff

• High ET photon

• NLSP Lifetime large ctNon-pointing

• Prompt NLSP decays Pointing

• Depends on SUSY breaking scale!

• Interesting Phenomenology

• From Eg , L, ct

• Can derive mNLSP and thus SUSY Breaking Scale

• Early Discover Potential

• N = 1 ; tan b = 1 ; sgn[m] = +1 ;

Mm = 280 GeV ; = 140 Gev

• O(1) fb-1

ATLAS

CMS Prel.100 pseudo

experiments

of 10 fb-1


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1 fb-1 is well into new territory:

Jets up to ~3-3.5 TeV

Di-jet masses up to ~5-6 TeV

Challenges: Jet energy scale,

Parton density functions (PDF),

underlying event, trigger, jet definition

Deviation from SM

CDF

Anomalous jets, dijet cross-sections

Substructure, contact interactions, high mass resonances


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Dijet xsec ratio and new Physics


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Efficiencies from data

Z’

High mass dimuons:

Tracking: alignment and propagation muons tracker important

As noted yesterday: Mass resolution (and so discovery potential)

not too strongly affected by tracker alignment scenario

Z‟, graviton resonances, large extra dimensions…


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Track Momentum resolution: 10-1000 pb-1

pT resolution integrated over h

Z peak visible with first rough alignments

100 fb-1/yrS

HU

TD

OW

N1000 fb-1/yr

200 f

b-1

/yr

3000

300

30

10-20

fb-1/yr

SUSY@3TeV

Z’@6TeV

SUSY@1TeV

ADD X-dim@9TeV

Compositeness@40TeV

H(120GeV)gg

Higgs@200GeV

2008 2010 2012 2014 2016 2018 2020

Early LHC Discovery Potential

Model Mass reach Luminosity (fb-1) Early Systematic Challenges

Contact Interaction < 2.8 TeV 0.01 Jet Eff., Energy Scale

Z’

ALRM

SSM

LRM

E6, SO(10)

M ~ 1 TeV

M ~ 1 TeV

M ~ 1 TeV

M ~ 1 TeV

0.01

0.02

0.03

0.03 – 0.1

Alignment

Excited Quark M ~0.7 – 3.6 TeV 0.1 Jet Energy Scale

Axigluon or Colouron M ~0.7 – 3.5 TeV 0.1 Jet Energy Scale

E6 diquarks M ~0.7 – 4.0 TeV 0.1 Jet Energy Scale

Technirho M ~0.7 – 2.4 TeV 0.1 Jet Energy Scale

ADD Virtual GKK MD~ 4.3 - 3 TeV, n = 3-6

MD~ 5 - 4 TeV, n = 3-6

0.1

1

Alignment

ADD Direct GKK MD~ 1.5-1.0 TeV, n = 3-6 0.1 MET, Jet/photon Scale

SUSY

Jet+MET+0 lepton

Jet+MET+1 lepton

Jet+MET+2 leptons

M ~1.5 – 1.8 TeV

M ~0.5 TeV

M ~0.5 TeV

M ~0.5 TeV

1

0.01

0.1

0.1

MET, Jet Energy Scale, Multi-

Jet backgrounds, Standard

Model backgrounds

mUED M ~0.3 TeV

M ~ 0.6 TeV

0.01

1

ibid

TeV-1 (ZKK(1)) Mz1 < 5 TeV 1

RS1

di-jets

di-muons

MG1~0.7- 0.8 TeV, c=0.1

MG1~0.8- 2.3 TeV, c=0.01-0.1

0.1

1

Jet Energy Scale

Alignment

Early LHC Runs: 0.1 to 1 fb-1


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Maybe nature has some REAL SURPRISES in store…

sphericity

Large extra dimensions,Planck scale ~ EW scale

Possible micro black holeproduction; decay viaHawking radiation intophotons, leptons, jets…

CMS and ATLAS might seethis with 1-100 pb-1 !

From P. DeJong

Moriond 2007


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Summary

• There are good reasons to believe that there is

something new at the energy scales accessible to the

LHC that could appear early.

• Indications are that ATLAS and CMS will be ready to

exploit this opportunity.

• Many studies documented in PTDR

• Much achieved, but much more to learn

• Focus on the first data (0.01 to 1.0 fb-1) from now until first

collisions

• Many improvements in tools and our understanding of our

capabilities are expected

• Initial detector performance and speed of optimization

will be crucial

toward new physics at the lhccharm.physics.ucsb.edu/people/incandel/incandela_lhc_taiwan_bs… ·...

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