# Presentation: 537916

## TRAIL TO THE TOP*

- HCP 2005
- Alvin Tollestrup
- 7/6/2005

- *This talk is my personal view of some of the events that have taken place over the last 25 years.  It is probably biased and it certainly will not include all of the great ideas (nor the names of their authors) that have lead to the incredible machines that are now being built at CERN.

**Notes:**
Thank you for inviting me
Last time was in 1982 at an IGFA conference for a VLA
In this talk I will cover some of the events that made the discovery of the top possible and have also made possible machines such as the tevatron collider and the LHC and the detectors.

## Slide 2

**Notes:**
ADA + Synchrotron for injection
Photon beam-> pair production. 
Capture by betron oscillation missing target.  Then Sync rad reduces the energy
Start only few electrons.  When one was lost could see step in sync lite!
Later shipped to Orsay where a linac was available for injection
19n 1964 with 10 e7 positrons and electrons say first e+e- collisions.
First observation and explanation of Touschek effect essentially intra beam scattering.

## Time Line

**1959 MURA workshop.  MURA= “Midwest Univ. Research Assoc.”**
**1959 CERN PS commissioned.**
**1960 AGS at Brookhaven commissioned.**
**1971 ISR commissioned.**
**1974 Budker demonstrates electron cooling.**
**1975  Stochastic cooling demonstrated at the ISR.**
**1-30-1976 Colliding Beams meeting at FNAL.**
**11-11-1978  Lederman decides to commission Tevatron first and pursue Colliding beams later.**
**1981                 commissioned.  1982 – 1983  W / Z**
**1983  First Tevatron  run.**
** ****1989  LEP  (First measurement of Z 1994)**
** ****1986 First 900 x 900 Tevatron Collider and CDF.  20 microbarns-1!**
** ****1988-89  First CDF physics run.  4 pb-1**
** ****Oct. 1992 Run 1a begins. Both CDF and D0 detectors on line.**

**Notes:**
MURA Midwest Univ Research Assoc.  Reaction against restricted access to Argonne and a push to get something in the Midwest.
Mention a few of the times

## Some Machine History

**Notes:**
This is a brief description of some of the steps along the way that I have been involved in.  It is not history as much as a personal story.

## Fall out from MURA and the FFAG

**MURA:  Very creative group.  Many inventions that are fundemental for colliders.**
**The FFAG (Fixed Field Alternating Gradient) was invented.  Like a cyclotron, the field is fixed and the cycle time is determined by how fast one can cycle the RF. Very high intensities possible.   It is having a revival as a candidate for neutrino factories!  Protons can circle both directions.**
**RF beam stacking and phase displacement acceleration**
**Studied beam instabilities.**
**First attempt at understanding orbit stability for stored beams.**
**Proton-Proton colliders suggested by Kerst.**
**1960 CESAR  (not Cornell!)  an electron storage ring at CERN ...model for ISR .**

- See “Development of colliders” by Pellegrini and Sessler  AIP Press.

**MURA**

**Notes:**
Some centers for machine development:  LBL, Cornell, BNL, CERN ISR, etc.  MURA deserves much credit for ideas that made CB possible.
Fixed Field Alt Gradient FFAG Machine.
Rep rate determined by RF cycle time Leads to very high intensity.
Circulate protons in either direction.  Kerst invented proton CB.
Beam stacking and RF manipulation of beam developed
Calculation of beam stability.  24 hours beam in T  evatron goes around 4 e9 times.  No modern computers.
Matt Sands undertook design study for a 300 GeV fixed target machine.  Same as 12 x 12 or 10 x AGS.
FNAL was built.

## Kerst  at MURA in Jan. 1956 proposes pp collider using two FFAG rings.Mura Study in 1959 proposed an FFAG colliding Beam machine.

**65’ tunnel**
**3 meter mag**
**180 m radius**
**Two x 12 GeV**

**Notes:**
Summer study was designed to gather support for an FFAG type machine.  MURA was studying both colliders and very high intensity ~15 GeV machines.
Matt Sands undertook design study for a 300 GeV fixed target machine.  Same as 12 x 12 or 10 x AGS don’t know which.
The idea of the cascade set of rings was proposed..

## 300 GeV synchrotrons!

Matt Sands outlined the first ideas for a 300 GeV synchrotron at the MURA work shop in 1959.  Exploited cascade machines.
He organized a study group (WAG) centered at Caltech to do a detailed study for a 300 GeV machine.  This was published in 1960.  The ideas were picked up by LBL, BNL, and CERN.
Big guys decide it’s a good idea but “professionals” should do it!
Ramsey Panel suggested high energy fixed target machine designed by LBL and a 1000 GeV collider at BNL.
Finally resulted in the Main Ring at Fermilab.

**Matt Sands outlined the first ideas for a 300 GeV synchrotron at the MURA work shop in 1959.  Exploited cascade machines.**
**He organized a study group (WAG) centered at Caltech to do a detailed study for a 300 GeV machine.  This was published in 1960.  The ideas were picked up by LBL, BNL, and CERN.**
**Big guys decide it’s a good idea but “professionals” should do it!**
**Ramsey Panel suggested high energy fixed target machine designed by LBL and a 1000 GeV collider at BNL.**
**Finally resulted in the Main Ring at Fermilab.**

**Notes:**
Remember the PS had just started and AGS not yet going.
Basic idea was to accelerate a beam in stages.  This has the advantage that the aperture in the final ring is small.
WAG consisted of Southern Calif Universities.  Berkley wouldn’t join because we suggested a certain equality among the members.
Published in 1960.
After many gyrations, resulted in Wilson building MT at FNAL.

## Wilson has $20 M Left over

- Decides to build an “Energy Doubler”.
- The Main Ring had worked at 500 GeV (just barely!).
- A ring of superconducting magnets in the tunnel could easily reach 1000 GeV.

## Superconducting magnets problems solvedduring the construction of the Tevatron.It is a miracle they work!

- Conductor:  Developed industrial suppliers.
- Cabling:  Strand to cable + insulation.
- Coil fabrication:  Invented laminated tooling.
- Force containment:  Invented collars from laminations
- Field accuracy:
- Quench protection:  0.5 M joule/magnet.  A magnet could destroy itself if it quenched.  And the beam is   1.3 Mj.  10 mJ / cm3 will cause the condictor to go normal.
- Cryogenics:  Tevatron was the most extended facility.

**The Tevatron furnished the base technology for all the future superconducting machines.**

**Notes:**
Small companies, 1 year lead time.  Great variability.  Wilson bought raw material and had competition for best strand
New technology on cable. Compress and wedge shape.
Invented insulation method.
Invented laminated tooling for molds.
Forces.  LHC  500 Kg-cm-2.  Heat capacity very Low. mJ in conductor can cause quench. Manly stabilized by He.  
Accuracy:  Invented laminated collars for containment and accuracy
Cryogenics major effort but technology available.

## 1976 FNAL  Magnet development

**Wilson winding a model coil**

**1976 FNAL  Magnet development**

**1 foot model magnet.  We  built more than 50 different models of this size.  The turn atound time between conception and test could be as short as 2 weeks.**

## Laminations/tooling

**Laminated tooling for forming the magnet coild.**

## Sample laminations from variousmagnets

## TEVATRON MAGNET CROSS SECTIONFIRST BEAM JULY 3, 1984

**Notes:**
Final cross section of Tevatron magnet

## Cross section of LHC

**Notes:**
Advances since the Tevatron.
Two magnets in one cryostat and iron shielding.  Possible because it is a PP collider.  The field go up in one down in the other.
The iron is saturated.  Better comuptation for magnet fields.  Iron helps support the forces.
Cold iron.  Enormous mass has long cooldown time.  Better refrig. Plants and more confidence in the reliablity of the magnets.
Superfluid He cooling.  Temp less than lambda point 2.17 K.
Much better conductor

## 1975-1980 

**Meeting on colliding beams, Jan. 1976,  using the “Doubler” against the MR.**
**     ****Proposals for colliding beams existed from the beginning of FNAL, but the proposed “Doubler” brought in new letters of interest.    Wilson asked me to organize a meeting.  It was held on 1-30-76.**
**.  ****Results:**
**“****Doubler” placed under MR instead of on ceiling.  Colliding Beams taken seriously.**
**Peter MacIntyre suggests Pbar-Proton in Tevatron.**
**I organized a small group of physicists to look at colliding beam physics.  This eventually morphed into CDF.**

**Notes:**
 Wilson had $20 M left over from FNAL construction.  Under Cost!
Started to use this for building an SC “Energy Doubler” Ring.  DOE didn’t agree this was his money!
I arrived in April 1975 on sabatical.
10 foot long magnet failed.  Start of 1’ program to explore the complexities of SC magnets. 
Started Factory. Parallel with 1’ program.

## Colliding beam meeting at 

**Colliding beam meeting at **
**FNAL 1-30-1976**

**Notes:**
Colliding beams meeting Jan 1976.  Walker proposal, Rubbia MacIntyre, Richter Cline.
Doubler moved from ceiling
Peter proposed pbar p in a single ring.
I started a study group that finally became CDF.
Over next two years we actively explored both pp between MT and Tevatron  200 x 1000 and the pbar p option.
1978 was a time of chaos.  Wilson Resigned. 

## 1975:  Result of Colliding Beams Meeting

## 6-10-1976  First beam stored in the Main Ring at 200 GeV

**6-10-1976  First beam stored in the Main Ring at 200 GeV**

**Notes:**
First store in MR.  Original proponents wanted 400 GeV in MR.  200 or a little more was probably the limit.  Live time short due to vacuum and resonances.

## Slide 19

## Slide 20

## Slide 21

## Slide 22

##                            What made CDF a great detector:Superb tracking chamber with B            Silicon vertex detector

**Silicon Vertex Trigger is the latest innovation for triggering on displaced vertices**

## 1.  Radiative corrections are ~ 

- Examples:

- 2.**Mass** **limits are set by:** Measure a limit on         and use Theory to calculate the cross section as a function of  mt .   This approach depends upon knowing the detector efficiency for a given decay mode and the theoretical branching ratio.

**Mass estimate before discovery**

## 1977:   b quark discovery at FNAL

- 1984:  DESY

- FB asymmetry   points to SM isodoublet for the b quark.  By 1992

- Direct searches for toponium at electron machines:
- PETRA               >23 GeV
- TRISTAN            >30 GeV
- LEP/SLC             > 45 GeV

- Mass limit climbs as available energy becomes higher
- Direct searches by electron colliders independent of decay properties.  But limited to  Mt < Ecm/2 = Ebeam

## year

**year**

**Top mass**

**CDF “Evidence”   CDF / D0 Discovery**

**Notes:**
----

## There are several different topologies:

- Both W’s decay leptonically:  two leptons + jets
- One W decays leptonically:  Lepton + 4 or more jets
- In addition, one or both of the b’s maybe identified by
-     the silicon vertex detector (SVX) or by the soft lepton
-     from one of the b’s semileptonic decay (SLT).
- 4. Both W’s decay hadronically giving 6 jets total
- 5. Confusion in jet assignment leads to multiple solutions
-     for        when the event is reconstructed.

**W’s may be virtual!**

## M. Shochet

## 1984

**The 1984 result raised hopes that Tristan could produce t tbar pairs.**

- M. Shochet

## Slide 30

## Slide 31

## Slide 32

## Start of run 1a

**First use of SLT tagging in CDF**
**e mu**
**e mu + ee + mu mu**
**e mu + ee + mu mu + b-> mu tag  **

**Start of run 1a**
**CDF lower limit from Run 88-89**
**                    ****91 GeV**

## Luminosity profile for Runs 1a and 1b

**Luminosity profile for Runs 1a and 1b**
**Both D0 and CDF detectors are active**

**CDF Evidence**

**CDF D0**
**Discovery**

## Slide 35

## D0 detector 1993-1995

**Hermetic, fine grained calorimetry              **
**Muon spectrometer**
**                            **
**Central tracking **
**                   **
**                 **
**     **

**D0 detector 1993-1995**

## At Start of run 1a        W’s are treated as real.

**Di-lepton:  1.2% e e Met + jets**
**                   ****1.2% mu mu Met + jets**
**                   ****2.4%  e mu +Met + jets**
**Lepton + jets:  15% e Met + 2 b jets**
**                          ****15% mu Met + 2 b jets**
**All jets:  44%**

**Major Background:**
**W + jets**

## D0 e mu + Met + 3 jets

**D0 e mu + Met + 3 jets**
**Early indications  Run 1a**
**Jan 10 1993**

## CDF e + 4 jet event

**CDF e + 4 jet event**
**Early indications Run 1a**

## The CDF  “Evidence Paper”4 – 22 - 94

**In the Summer of 1993, there was intense speculation on what was being found at the Tevatron.  CDF had shown enough information so that conclusions about the top were being drawn by physicists outside of the group.**
**Inside CDF there were 3 groups studying the SVX, a group working on the SLT tag, at least 3 groups working on mass reconstruction, a group analyzing the dilepton channel  and a group studying   jet angular and Et distributions.**
**A godparent committee was appointed and It was decided to write 4 short letters to PRL: (1) dilepton search, (2) lepton + jets with SLT jet tagging, (3) lepton + jets with SVX jet tagging, and (4) a summary paper.  A collaboration meeting in October 1993 avoided this disaster.**
**Work began on a comprehensive paper to PRD with a short announcement to PRL.  This culminated in the “Evidence...” paper being submitted 4-22-94.**

## G. H. Hardy and J. E. LittlewoodTrinity CollegeCollaboration Axiom’sFor working on Riemann’s Hypothesis

**Axiom 1.  It didn’t matter whether what they wrote to each other was right or wrong.**
**Axiom 2.  There was no obligation to reply, or even read, any letter that one sent to the other.**
**Axiom 3.  They should try to not think about the same things.**
**Axiom 4. To avoid any quarrels, all papers should be under their joint name regardless of whether one of them had contributed nothing to the work.**
**From Marcus du Sautoy,   “The Music of the Primes”**

## Does the SVX really work?

**Does the SVX really work?**
**First PRL paper June 1993.  Data from first half of Run 1a**

## Slide 43

## “Evidence”  CDF   PRL July 1994

- “Evidence”  CDF   PRL July 1994
- Run 1a

**Data and background**

**Acceptance vs mass**
** ****for different tags**

**Data and background after SVX / SLT tags**
**Found that there was only a 0.26% probability that backgrounds could have produced the 15 events in the data.**

## Run 2:  Best Single measurement:

**Concerns:**
**Z + 3 jet events have 2 tags when .64 are expected.**
**Crossection large enough to account for all W + 4 jet events.**
**Other evidence than counting;**
**Kinematic jet distributions support t tbar production.**
**Mass fit favors t tbar by 2.3 sigma over W+QCD jets.**

**Run 2:  Best Single measurement****:**

## D0 results from run 1a

**Three papers in PRL on Run 1 a data;**
**First   Jan. 1994.  Mt > 131 GeV.  Used (e mu  and e e) + jets and            e + jets and mu + jets.**
**Second  Nov. 1994.  Same channels as above, but now  used low momentum muons associated with jets for b-tag.  9 events with 3.8 background.    2.7%.  Final paper in PR May 1995**
**Conclusion: “Measurement consistent with CDF “Evidence” and of comparable sensitivity, does not demonstrate the existence of the top quark”  **
- On to run 1b and discovery.

## CDF Discovery  paper PRL April 1995

**CDF Discovery  paper PRL April 1995**

## D0 Discovery paper PRL April 1995

**D0 Discovery paper PRL April 1995**

**17 events observed**
**3.79 +/- .55 ev. Background**
**4.6 sigma**

## Slide 49

## The past vs the future

**Vast change over the last 50 years from university centered physics to large facility physics.**
**National Laboratories once controlled by local users have given way to regional labs.**
**Control now resides with the “Provider of Funds”, The “Laboratory”, and the users thru “Committees”.**
**Creativity now resides in:**
**The management level, i.e. people that can bring large projects  into reality.  Tends to be older people!**
**At the technical  and physics level within the project.  Young physicists can win here!**
**The Hadron Collider is unique in that it treats so much physics in a completely democratic manner.  This leaves great space for students to make discoveries.**
**The LHC will teach us if we need the ILC.**
**We mustn’t forget that we really want to understand Nature.  Neutrino physics, weak decays, double beta decay must also be supported.  Unlike colliders, they are specialized experiments that require a big investment.**

## Lets all hope thatMalcom Brown willnever write:

## Slide 52

## Slide 53

## But that could be the most exciting discovery of all!

Thank you 
And thanks to the conference 
Organizers!

**Thank you **
**And thanks to the conference **
**Organizers!**