# Presentation: 523247

## Considerations for and Examples of a Linear Collider Physics Program

- May 10, 2001
- Joel Butler
- Fermilab

## Goal of This Talk

- The Linear Colliders we are discussing are capable of producing a few hundred fb-1/year
- We hear many comments about different running modes to study particular physics. _I was asked to address the following issues:_
**Are the various running modes compatible or do the various physics topics have conflicting requirements?**
**Do the luminosity books balance – that is, **_**can the expected luminosity deliver the advertised physics**_**, or is the luminosity inadequate or severely overbooked?**
- Other e+e- colliders, _**albeit with different production characteristics for the physics of interest**_, have suffered from problems because optimal running modes for various topics were in conflict and you were forced to chose which physics to emphasize – you couldn’t do it “all at once” as you can with a hadron collider.

## Outline

- What are we trying to accomplish with this class of  machine?
- Possible machine operating modes
- What sets the context in which we can proceed to discuss these “operational” issues?
- This will include a  review of the key physics issues, but considered from the viewpoint of their requirements on the machine operating mode and demands on its luminosity
- Possible Physics knowledge “initial conditions” or “scenarios” and associated run plans
- Conclusions

## What are we trying to achieve with this class of  machines

**To **_**elucidate**_** the nature of Electroweak**** ****symmetry breaking**
**Issue is not just the discovery of a Higgs-like object**
**A standard model Higgs has serious issues associated with it. It receives radiative corrections from heavy objects which are  quadratic in the mass  and have to be removed by highly “delicate”  fine tuning procedures**
**If the problem is “cured” by invoking new symmetries such as supersymmetry, then the symmetry is obviously broken, so we have to understand that. ****Ditto for  any new “dynamics”**

**It is likely that some of the particles associated with this phenomenon will be seen before an LC is operating.**** **_**The discovery of such particles may  open up this area of experimental investigation of EWSB, but is not likely to close it out**__** .**_** ****The initial observations will raise new questions and may tell how best to proceed to answer them.**

## Bad Baseball Analogy

- Baseball symmetry study

## Contexts for Proceeding with the Discussion

- The machine
- Possible operating modes
- Our _current_ physics understanding
- The **“then year”** physics Scenario

**This exercise necessarily involves some crystal**
**ball gazing. At best, we can identify broad classes **
**of situations we could confront and ask whether the**
**machine we can imagine has enough luminosity  and operational flexibility to deal with them successfully**

## The machine context (grossly simplified)

- Take a very simplified view of the “machine”
- Energy in CM 		500-800-1000 GeV
-  Beam smearing		3-4%
- Luminosity			2-3 X 1034/cm2-s
- e- polarization		80%

**I am ignoring the issue of e****+**** polarization. It seems to be viewed as “useful” but not crucial. There will also be other modes of running such as ********,  e****-****e****-****,********or very low energy running. **_**For now, I assume these do not interfere with program I am going to describe.**__ _

**There will be (optimistically)  200-300 fb****-1****/year (10****7**** s) or  1000-1500 fb****-1**** over the first 5 years of operations.**

## Operating Modes - I

**Sit **– for a particular topic, e.g. study of branching fractions of a Higgs at a known mass, sit at the center of mass energy that maximizes that physics – which means best tradeoff between signal, background, resolution...
**Span**** **– sit at the highest energy obtainable. This obviously provides a broad look and produces physics over a wide range of topics – but is not necessarily “optimum” for any of them
**Scan** – study a region where there is a threshold or transition of some kind by scanning the center of mass energy from just below to above the area of interest to see how things behave as they turn on

## Operating Modes - II

- Polarization
- Can enhance certain kinds of physics –especially asymmetries and interference effects
- Can turn off or reduce certain kinds of background
- Does polarization intended to enhance some physics hurt other physics you would like to do at the same time?

## Electron Polarization

_**Comment: How this works at NLC, by way of SLC/SLD:**_
**Bunch trains (120 Hz) are polarized at the source by a passing laser light **
**through a Pockels cell –a nonlinear optics device based on applying a voltage across a crystal- which manipulates the index of refraction.   **
**This light then falls on a Photocathode of GaAs, which emits polarized electrons.  The individual bunch trains acquire ~80% polarization. **
**In “randomized polarization” running, the sign of the voltage on the Pockels cell is random (by train)  so 1⁄2 the bunch trains have 80% RH polarization and 1⁄2 have 80% LH polarization. The voltage on the cell is provided to the experimenters for each bunch train so they can sort their data into  (mostly) “RH” or “LH” samples for polarization studies or ignore the voltage and add everything up  **
**If you want to “emphasize” one polarization, you can fix the sign of the Pockels cell voltage and get 80% polarization for your preferred handedness– called “polarized” running. **

## LBS Worksheet

| CM
Energy | Run
Duration | e-
Polarization | Goal |
| --- | --- | --- | --- |
|  |  |  |  |
|  |  |  |  |
|  |  |  |  |
|  |  |  |  |
|  |  |  |  |

- I am more interested in what kind of conditions are best for
- various physics topics,  how sensitive they are if you are not
- at their optimum, and how/whether various running
- conditions can coexist gracefully.  A few detailed scenarios
- will be discussed, but only  towards the end of the talk.

## Current Physics Context - I

**There are many reasons to believe that wonderous, **_**unanticipated**_**  new discoveries await us at higher energies**
**Having said that, I want to investigate how this machine could address the main issues of ElectroWeak Symmetry Breaking under various unfolding scenarios**
**But keep point 1 in mind by using whatever flexibility exists in addressing point 2 to retain the highest possible  openness to new physics, **_**especially by providing lots of running at energies close to the top machine energy **_

## Current Physics Context - II

- Higgs physics – Based on our current understanding, we expect that at least one Higgs-like object will have been found at the Tevatron or LHC before this machine turns on. However, the SM model Higgs has serious problems since its radiative corrections lead to quadratic divergences. This can be fixed by renormalization but if the next relevant scale is the Planck scale, it raises the “naturalness” issue and the “hierarchy problem” – why is the Higgs mass so low compared to the Planck scale?

## Current Physics Context - III

- A natural cure is to have another family of particles at or near the EW scale which contributes to EWSB
- SUSY is considered by many the premier candidate
- But whatever appears it will be important to study it in detail to understand
- Its relation to the Higgs sector
- Since it is likely to associated with a new symmetry, which would be broken, or new dynamics, we would need to study that as thoroughly as possible, and understand how it works and what it implies, if anything, for higher energy behavior

- I use SUSY in the following exercise because it is expected
-  to have  a rich spectroscopy within the reach of a 500 GeV
- Linear Collider, is very dependent on  polarization and is
- therefore very demanding on machine operating conditions

## Why Study the Higgs?

- Once you know the mass of the “Standard model Higgs”, everything else about it is fixed
- If you see a Higgs-like object and want to “prove” it is the SM Higgs and that it alone is really the object that provides mass to the gauge bosons and all other particles, you should verify that it has exactly the properties “prescribed” by SM
- If the observed Higgs is not truly the Standard Model Higgs, its couplings and decay properties should show deviation from the highly defined SM Higgs, e.g:

**The branching fractions in the SM are completely determined**
** ****once the Higgs mass is known. Departures signify a more**
**complex Higgs sector and give clues about its nature**

## Everything You Always Wanted to Know about the Higgs –a.k.a the Higgs Profile

- Mass
- Width
- Spin
- Parity
- CP
- Coupling to gauge Bosons
- Coupling to fermions
- Charge 1/3 quarks
- Charge 2/3 quarks
- Leptons
- Higgs self couplings
- Triple coupling
- Quartic coupling

- We’ll go through this program seeing which pieces require **scans**, which **continuum running -span**, which **sitting at optimal energies**. The question is whether it is likely that the luminosity and other requirements can be met by our collider under all circumstances.

## Higgs Physics for the Theory Challenged - I

_**Production Mechanisms:**_

- Z Higgs-strahlung

- Asymptotic behavior 1/s
- Depends on  gZZH
- Threshold behaviorhz
- Not very sensitive to polarization

- W (Z) Fusion

- (Z fusion is suppressed by NC/CC ratio and is  lower by a factor of 10)

- Asymptotic behavior
- Depends on  gWWH
- Dominates at high CM energy
- Much reduced  by RH polarization

## HPTC - II

- Total Width and Branching Fractions

-  goes from
- ~0.01 to ~1
- GeV as W,Z
- Channels open

- ~0.5MH3

- Some tree level formulae:

## HPTC - III

- The Higgs partial widths are strong functions of both  the Higgs mass and the decay product masses.

- If the Higgs mass is well below 2MW, there are several  decay modes involving fermions available, which have appreciable branching fractions and the total width is small– _too small to measure directly from mass reconstruction_

- If the Higgs mass is over 2MW  but <2Mt, since the ratio, the only appreciable branching fractions are WW and ZZ, because

- Only the VV branching fractions and the total width can be measured directly

- If MH>2Mt, it will be possible to measure the top branching fraction directly.

## HPTC - IV

- If you can’t measure a coupling directly, then you have other methods:
-  gvvH can be measured from cross sections
-  gttH can be measured from the cross section for Higgstrahlung off a top pair, but this requires high energy and high luminosity
-  gttH may be inferred from  Hgluon-gluon which is dominated by the loops containing a top (model dependent!)

- For MH<200GeV, can get total width from a branching fraction measurement and a measurement of a the corresponding coupling constant by another means – i.e. from a cross section (Some of you may remember this from the J/)

- If the Higgs sector is more complicated – e.g. SUSY– there might be more Higgs particles. However, since they are responsible for  particle masses, they are constrained to make up the equivalent SM coupling:

- Departure from SM predictions new physics.
- This sets a luminosity bar for the e+e- collider

- e.g

## Higgs Physics for the Experimentally Challenged 

_**Missing Mass Method for Isolating a Signal**_

- In the process e+e-Z+X, a measurement  of the Z momentum vector,
- allows one to compute the invariant mass of the the recoiling state “X”,
-  in this case mainly the Higgs:

- The Z signal can be most easily isolated and EZ measured most accurately from Z e+e- or Z+-. Can use jet-jet signal, also.

- The ability to see a mass bump recoiling against a measured Z, gives one a _**model independent measurement**_ of the total number of Higgs’ produced. Reconstruction of the individual decays then gives the actual absolute branching fractions (and any “invisible part”).

- _Rates (ZH): _      300 fb-1 X  250 fb = 75,000 Higgs produce For Ze+e-,+ (6.8%), we get  5100 events
- Add Zbb,cc,(30%) X0.5 (recon,background), we get    16,350 event

- Beam
- strahlung

## Energy Considerations

| CM 
Energy | Cross
Section
(pb) | Rel
Lum | Product |
| --- | --- | --- | --- |
| 250 | 0.25 | 0.5 | 0.125 |
| 350 | 0.14 | 0.7 | 0.098 |
| 500 | 0.06 | 1.0 | 0.06 |

- You gain about a factor of two by sitting at the peak of the cross section rather than at 500 GeV
_**250 GeV virtues:**_
-  highest rate
- Lowest background – no higher energy processes
- Lower beamstrahlung and better resolution on Z energy
_**500 GeV virtues:**_
- Can get other physics e.g. SUSY
- Z and Higgs in separate hemispheres

- Sit
- (weak)

- Not S channel
- resonance
- No sharp energy
- dependence
- ~1/s

## Spin and CP

- The spin of the “Higgs candidate” can be determined by the behavior of the ZH cross section near threshold. Each point of the scan is 20 fb-1. The Higgs mass is taken to be 120 GeV/c2
**BUT**
**It can also be determined by the Z angular distribution in the continuum :**

- The CP even or odd nature of the Higgs candidate
- can be determined by measuring the angular distribution
- of the Z with respect to the beam direction in the lab

- A sin2 behavior implies CP even, a (1+cos2Z) CP odd,
- and a cos  term mixed CP, i.e. CP violation

- Scan

- or Span

## Multi-Higgs Coupling

- Cross sections are small:
- ~10’s to 100’s atobarns.
- This gives  dl/l of ~ 20%
- accuracy in about 5 years

- There is not enough
- Luminosity to measure
- Quadrilinear coupling!!

- 1/2MH2

- Span

## SHPTC – V

- Minimal SUSY has two complex scalar fields, which give mass to the Zo, W+, and W- and have 5 fields left over to form new Higgs’s: **h****o**** (CP even), H****o****(CP even), A****o****(CP odd), H****+****, and H****-****.**There are two vacuum expectation values and **tan ******** = v****1****/v****2**. The  two neutral Higgs mix to form the ho and Ho  and the mixing angle is called ****. Only one of the masses  are one angle are independent.

**Mass degeneracy:**

## Decay Modes and Branching Ratios

- Decay Modes of SUSY Higgs:
- ho : As in SM
- Ho: can go to same modes as
-       ho and hoho if mass is
-       > 250 GeV
- Ao: is not allowed to go to ZZ
-        or WW. Will go by bb
-        , Zh, or tt depending on
-        MA.
- H+:  or, if heavy tb

-   dependence of decay modes:

- Higgs-gauge bosons couplings
- relative to SM Higgs

_**Decoupling Limit**_**: if ******** is near**
**90****o**** (large tan ********) and ******** is near 0****o****,**
**then only h****o**** has significant**
**couplings and SUSY looks like**
**SM. This occurs if M****A**** is large.**

## SUSY Higgs Cross Sections

- Typical cross sections are
- order 100-10 fb-1 for
- Ho and order of  1-20 fb-1
- for Ao at 350 GeV

- There will be enough
- luminosity to have a shot at these
- if masses are below 300 GeV.
**E****cm**** of 800-1000 GeV definitely **
**extends the reach**

- Typical cross sections for the
- H+ are 10-100 fb-1 and for Ao
- are around 10 fb-1 at 800 GeV

- Span

## Heavier (single) Higgs

- For MH> 200 GeV/c2, it decays almost 100% into WW and ZZ until 350 GeV/c2  where       is permitted.
- You can still measure MH, ,  and the quantum numbers.

- The main branching ratios are ZZ and WW.For  SM Higgs:

- Polarization of vector mesons:

- Trilinear coupling: more significant in this scenario?

- Top coupling: if MH>350 GeV, the branching fraction to top is 10-20% and the cross section for  a 350 GeV Higgs
- (ZH)= 1.3,1.5,1.2 fb at 500,600 800 GeV
- (W)= 3.9,12.5,40 fb at 500,600,800
- If MH~200 GeV, use t-tbar-Higgs:

**Probably**
**span**

- span

## A 0th Order SUSY Primer-I 

**Recall that in SUSY, for  sparticles “L” and “R” refer to **
**having the same quantum numbers, e.g. weak isopsin and hypercharge, (except for spin) as the normal “lefthanded electrons”  and “righthanded electrons”, respectively. All couplings are the same as for normal particles e.g. only “LH”**
**sparticles couple to W’s.**

**R-Parity: **

**SUSY makes contact with every “benchmark”  physics process: CP violation, flavor violation,  baryon and lepton number violation.**

**A multiplicatively conserved quantum number, which is 1**
**for particles and –1 for sparticles. This is not a requirement of SUSY but, if imposed, provides an easy way to avoid various problems. If conserved there is the lightest SUSY particle, the “LSP”, is stable.**

## A 0th Order SUSY Primer-II

- The SUSY Spectrum depends in detail on SUSY breaking models and their many associated parameters. The lightest SUSY partilce is expected to be the “neutralino” – An admixture of the superpartners  of the gauge bosons.
- in many models, several superparticles have masses below a few hundred GeV
- and could be detected and studied by the machines we are discussing. **The mass**
**spectrum is the key to pinning down SUSY breaking parameters**

- All these models have
- a neutralino, chargino,
- and at least one slepton
- below 250 GeV. Only
- mSUGRA has a squark
- (stop) below 400 GeV.

**Is a SUSY program**
**“****compatible” or in**
**conflict with the **
**Higgs program?**

## SUSY Branching fractions

| Decay Mode | Fraction |
| --- | --- |
|  | 49.7% |
|  | 42.4 |
|  |   7.8 |
|  | 58.6 |
|  | 22.2 |
|  | 10.1 |
|  | 66.3 |
|  | 33.7 |

| Decay Mode | Fraction |
| --- | --- |
|  | 61.5% * |
|  | 31.9 |
|  |   6.6 |
|  | 99.0    * |
|  | 54.4 |
|  | 24.2    * |
|  | 21.4    * |
|  | 64.6    * |
|  | 35.4    * |
|  | 86.2    * |
|  | 13.7    * |

**Illustrative only.Varies wildly**
** ****with model/mass spectrum.**
- *quasi two-body decay

- Smuons work the same as selectrons

## SUSY Cross Sections are Polarization Dependent

**Note: these are DRAMATIC effects, not subtle **
**ones!!! Also, ZH is only slightly effected by**
**polarization. RH polarization kills W-fusion!!!!**

- ZH

- ~  ~
- eLeL

- ~  ~
- eLeL

## Typical Polarization Studies

-  Study of gaugino,
- Higgsino content of
- Neutralino (mixed)

- Study of gaugino
- Or Higgsino
- Character of
- Charginos

## SUSY Mass Measurement

- Emin

- /

- Emax

- Note: We can get the neutralino mass for “free” from the measurement
- of the electron energy!

- For a three body decay like

-      , you can see that if you use

-  a limited range of Mqq, you can sort of capture the same effect.

- Beam
- strahlung

## Polarization and Backgrounds

- Going to right handed electrons can heavily suppress WW background,
- which is most of cross section

- Reminder: (ZH) is not very sensitive
- to polarization!  It goes up about 15%
- for left polarization and down by 15%
- for right polarization from the un-
- polarized case.
- However, W fusion (H) is. RH
- Polarization turns off the W coupling!

**This means that there is NO SIGNIFICANT conflict between **
**between manipulating the polarization to do SUSY studies and**
**accumulating statistics on a Higgs. Only possible problem would**
**be if you want a lot of RH polarization running and you need the **
**W fusion process for the Higgs to do some physics.**

## SUSY Scans

- The SUSY mass spectrum can be quite complex. There can be several states (if lucky) within the machine’s energy window. The left and righthanded sfermions do not have to have the same mass. There can be a lot of mass mixing between states.

- It seems desirable to vary the energy to see how the physics changes and to scan in the vicinity of thresholds to confirm
- quantum numbers, etc. SUSY is its own background!

- A SUSY program of investigations will involve varying energies as well as polarizations. We saw that the impact on the Higgs studies is not terribly great if you are running  at HIGHER than optimal Higgs energy to do   SUSY studies.

- Of course, this would not necessarily be true if SUSY were at the
- light end of predictions or you found the heavier SUSY Higgs since they could be heavier than some of  the sparticles. **This would be a good problem to have!**

## SUSY Threshold Scan

**From Martyn and Blair, LCWS, SUSY**
**Spectrum is similar to the first set above**

- Susy scans  impact on other programs will depend on mass spectrum energy. Significant running with RH polarization (but you are running this way 1⁄2 of the time) or at low energy might hurt the Higgs or Top program or “new physics”.

- 10 energy points at 10 fb-1 each

- Typical uncertainties on mass are 0.1 – 0.3 GeV/c2 or a few parts per mil.
- From these, one can fit for SUSY breaking parameters in various models.

**Note a strategy with only 4 points – **
**above, below, 2 on the rise – has also **
**been proposed. **

## Top Physics

- The Top offers special opportunities for new physics because
- The large mass gives it strong couplings to many proposed new physics scenarios
- Couplings of Top quarks to EW gauge bosons are “largely untested” (and not all of this will be done at hadron colliders)

- Topics near threshold (350 GeV)  ~1000fb
- Top Mass and Width – scan over 10 GeV around 2mt.
- Top Width – height of 1S 1/. The peak shape is also sensitive to t.
- Top quark Yukawa coupling to the Higgs
- Top quark threshold region in polarized e+e- collisions is sensitive to CP violation in top couplings and forward-backward asymmetry near threshold also gives info on  t.

- Topics in continuum (500 GeV)~600fb
- ttH already discussed
- Top mass may be measured well in continuum – work in progress
- Anomalous couplings: analyze the energy and angular distribution of charged leptons and b-jets to see if they agree with SM predictions. There are CP violting electirc and magnetic dipole terms that could signify new physics

- Scan (few 10 fb-1) and sit
- <~100 fb-1 (theory limited?)

- Sit. Anomalous couplings
- can use 500 fb-1 or
- more

## Physics Context at Turn-on or the “then-year” Physics Scenario

- We will have results that we do not have today from
**Tevatron: Nearly anything discovered at the Tevatron, Higgs, SUSY, or “other” would GUARANTEE that there was something very interesting to study at an LC**
**LHC: The LHC will almost certainly have a few years of running before an LC program will start. Much would depend on what was seen and how clear a picture emerged. The LHC experiments will have had a lot of time to study any new objects.**

- If nothing is seen at the time the LC turns on, it would be first
- necessary to demonstrate in this new, cleaner environment that
- nothing was missed.

## The “Then-year” Physics Scenario

- Any LC program depends on
-  What they learn at Tevatron and LHC– we should assume that their ability to learn things about Higgs, SUSY, or any new phenomena will improve as
-  running approaches and more people turn their attention to these issues
- Results emerge to guide people’s thinking and analyses
-  Lessons learned from other physics (propagator/rare process) and theory
-  Continuing studies of the kind now going on world-wide to understand how to exploit an LC

## Possible Scenarios at LC turn-on

- 1 Higgs seen and evidence for SUSY – study Higgs, look for other Higgs’, thoroughly explore SUSY
- >1 Higgs seen and evidence for SUSY
- 1 Higgs seen but nothing else – Study the Higgs to death, look for other Higg’s and make sure SUSY not missed
- >1 Higgs seen and no SUSY evidence seen – study all Higgs thoroughly and make sure SUSY not missed
- 0 Higgs seen and no SUSY seen – make sure nothing is missed in cleaner environment and look for new phenomena

**Don’t forget that one must be also protect the **
**opportunity to see something quite unexpected and**
**be prepared to pursue anything new that shows up**

## Sample run plans for the first ~5 years

- _1 Higgs seen and evidence for SUSY_

- Risk taker

- 100 fb-1 max energy
- 200 fb-1 at Higgs optimum
-      if step 1 indicates
- 700 fb-1 at max. energy
-     or scan if  SUSY
-     scenario requires it.

- _1 Higgs seen but nothing else_

- _0 Higgs __seen__ and no SUSY seen_
- _and no new physics_

**500 fb****-1**** at 500 GeV(or highest energy) for new physics, WW scattering**
**200 fb****-1**** at tt threshold**
**Consider Giga-Z and WW threshold running**

**100 fb****-1**** at max energy(quick**
**    ****check for new physics or**
**    ****missed SUSY)**
**300 fb****-1**** at Higgs optimum**
**100 fb****-1**** near top threshold**
**500 fb-****1**** at max energy**
**   ****(new physics,**
**    ****top anomalous couplings)**
**Consider Giga-Z running **

- Results will guide further running

## Conclusions –I  

- Things you can do well: branching fractions and quantum numbers of Higgs, in depth SUSY studies for sparticles in  this mass range....
- Things you can’t do well with this luminosity: trilinear Higgs couplings, ttH
- Things you probably can’t do at all with this luminosity: quadrilinear Higgs couplings...
- Things you can do with this luminosity but are much better at higher energy: trilinear coupling, ttH, and of course, you have better mass reach for heavier SUSY particles, heavier Higgs, and more reach for new phenomena
**The potential for conflicts in operational modes that could drastically reduce the physics reach is low because**
-  Most physics is not sensitive to the precise CM energy. The production mechanisms do not involve s-channel resonances (**if there were new unforeseen ones, I somehow imagine we would consider this an opportunity rather than a problem!)**
- the machine will normally alternate polarizations,
- there are multiple ways of measuring most quantities,
- once these phenomena begin to manifest themselves, some paths will be eliminated and others will be shown by the results to be the most productive to pursue.

## Conclusions - II

- There is enough luminosity to realize an excellent program, especially if SUSY turns out to be correct since there the ability to manipulate polarization really pays off
- The various running modes are not so badly in conflict that major physics will have  to be sacrificed or the program will have to be tuned in a way that could compromise ability to see unanticipated phenomena, provided
- Polarization does not cost much luminosity
- Changes in operating mode do not involve big inefficiencies (realignment, retuning) which sap integrated luminosity
- Further study will clarify which approaches are best for each measurement and search. Hopefully, people will keep operational realities in mind as they develop and advocate various approaches.
- Integrated Luminosity over the first N (5) years is critical – chose a technical approach that will achieve design luminosity quickly and maintain high efficiency. This should include an analysis of failure modes and maintenance issues
- Energy must be upgradeable in a straightforward  manner to of order 800-1000 GeV and beyond  at this site

## Baseball slide 2

- Red Sox Victory
- 6th game
- 1975 World Series

- Red Sox Defeat
- 6th game
- 1986 World Series

- Lesson: Make sure you have the best people in the game
- at the key moment

## Credits and References

**People who deserve credit for anything good in this talk but no**
**blame for my mistakes:**
**	****Michael Peskin, Paul Grannis, David Burke, Chris Quigg, Steve Holmes**
**	****Carla of the Psychic Hotline**
**	****The “breakfast club”: Chris Hill, Adam Para, Hugh**
**	****	****Montgomery, Andy Beretvas, GP Yeh**
**	****All the Linedrive  and Circle Line speakers **
**Some Useful References:**
**	****Proceedings of Snowmass 96**
**	****Perspectives on Supersymmetry, editor Gordon L. Kane**
**                  ****http://www.bostonredsox.com/**
**	****The Higgs Hunter’s Guide, Gunion, Haber, Kane, and Dawson**
**	****	**** ****(still useful after all these years)**
**	****LCWS 2000**
**  ****	****Tesla TDR**
**	****Physics at Run 2**
**	**_[http://store-yahoo.com/](http://store-yahoo.com/sportstation-steinersports/)__[sportstation](http://store-yahoo.com/sportstation-steinersports/)__[-](http://store-yahoo.com/sportstation-steinersports/)__[steinersports](http://store-yahoo.com/sportstation-steinersports/)__[/](http://store-yahoo.com/sportstation-steinersports/)_
**	****The Case for a 500 GeV e+e- Linear Collider, American Linear Collider **
**	****	****Working Group**
**	****http://www.whitesox.com/**
**	****many, many, many more**