# Presentation: 090503

## Passing the Baton:

***Tevatron-LHC Team***

*Young-Kee Kim*
*The University of Chicago and Fermilab*
*Colloquium*
*Fermilab, August 9, 2006*

## Tevatron: 2 TeV proton-antiproton

- LHC: 14 TeV proton-proton

- Now    Nov ‘07      Sept ‘09

## Don’t tell me

- you discovered Higgs!!

## Today

- Tevatron at Fermilab
- x104 bigger, x106 higher energy

- Many generations of Accelerators created.
- Discovered many surprises.

- 1929

- Ernest Lawrence
- (1901 - 1958)

- Particle physics field has been tremendously successful in creating and establishing “Standard Model of Particle Physics”answering ”what the universe is made of” and “how it works”. Answers themselves led to even more questions!

## top quark

- anti-top quark

-  Z

- W+, W-

- .     .     .     .

- e    e- u  d   s    c      b

-   gluons

-  Elementary Particles and Masses

- e    e+ u  d   s    c      b

- -   -   -                       -   -   -     -       -

- ( Mass proportional to area shown: proton mass =     )

*Are they the smallest things?*
*Why are there so many?*
*Where does mass come from?*

## Dark Matter - What is it?

- Everything is made of electrons, up quarks and down quarks.

*Dark Matter - What is it?*
*Can we make it in the laboratory?*

## Accelerators

- particles
- anti-particles

*Do all the forces become one?*
*Extra hidden dimensions in space?*
*Where did all antimatter go?*
*Universe; not only expanding, but accelerating! Dark Energy*

**Notes:**
We believe that there is an underlying simplicity
behind vast phenomena in nature.
Do all the forces become one?
At high energy, do forces start to behave the same as if there is just one force, not several forces?
Extra hidden dimensions in space?

## Slide 8

## Slide 9

## Origin of Mass

***Origin of Mass***
***Unification***

***Energy Frontier Colliders***

## Energy Frontier Colliders

- e+e-
- e-proton
- proton-proton

- Today

**1970 **              **1980**               **1990**               **2000**               **2010**               **2020**              **2030**

- LHC - 14 TeV

- ILC

- TEVATRON - 2 TeV

- HERA

- LEP,SLC

-      CLIC
-  Collider

- The world HEP community endorsed the ILC as the next accelerator
- to extend the discovery reach of LHC.

## International Linear Collider (ILC)

- 0.5 TeV → ~1 TeV e+e- collider

- discover new particles                 discover laws of nature

## LHC Challenges:

- Energy: 14 TeV =     7 x Tevatron
- Length: 27 km =     4 x Tevatron
- Magnetic Field: 8.3 T =     2 x Tevatron
- Beam Energy: 350 MJ = 250 x Tevatron
- Bunch Collisions: 40 MHz =   20 x Tevatron
- Instantaneous Luminosity =   60 x Tevatron
- # of Collisions in an event =   10 x Tevatron
- Data Rate: 1 Terabyte / sec =   50 x Tevatron
- # of Detector Channels: 100 M = 100 x Tevatron
- # of Scientists (~2500/expt) =     3 x Tevatron

**LHC**

- LHC: proton-proton

- Tevatron:
- proton-antiproton
- 7 accelerators

**Notes:**
How much is 350 MJ?
Kinetic energy
	- 1 small aircraft carrier of 104 tonnes going 30 kph
	- 450 automobiles of 2 tonnes going 100 kph
Chemical energy
	- 80 kg of TNT
	- 70 kg of (Swiss?) chocolate
Thermal energy
	- melt 500 kg of copper
	- raise 1 cubic meter of water 85 C: “a tonne of tea”

## Accelerator Challenges

- LHC

- Tevatron

- Tevatron team in
- LHC commissioning

## Unanticipated Beam Incidents

- Each proton bunch is like a bullet!

- Tevatron Beam Incident

- LHC beam power = 250 x Tevatron!

- Tevatron: Single Event Failure in Collision Hall Electronics

- LHC, ATLAS, CMS failure modes will not be the same.
- Importance: monitoring, diagnostic tools, collimater system, shielding,
-                     communication between machine and experiment teams

## Experimental Challenges

- CMS: 14 m x 22 m, 12.5k tons
- 108 channels

- ATLAS: 24 m x 45 m, 7k tons, 108 channels

- CDF: 106 channels

- DØ: 106 channels

-  Collecting data at energy frontier is non-trivial:
-  Detector’s radiation safety issues
-  Small bunch spacing and large # of interactions per crossing		 event synchronization, complex event topology
-  Unexpected problems!

## Commissioning CDF and DØ Detectors

|  | Tevatron | LHC |
| --- | --- | --- |
| Cosmic Ray Run
Engineering Run 
with Partial Detectors | 2000
Oct. 2000 | 2006 |
| Detector Completion | Jan. 2001 | Spring 2007 |
| Commissioning Run | Mar. 2001 - Feb. 2002 | Nov 2007 (1 TeV)
Spring 2008 (14 TeV) |
| Beginning of Physics Run | Feb. 2002 | 2008? |

-  Timing-in Electronics:
-  Across all detector subsystems, and across trigger subsystems
-  Commissioning beam loss monitors
-  Calibration and alignment of each system
-  Establish “stable” detector configuration and “stable” trigger table

## Unanticipated Problems

- CDF silicon detector modules were dying.
- Breakage of a wirebond carrying power.

- Resolved!

-  Some broke
-      during a trigger test at ~20 kHz
-  Oriented orthogonal to 1.4 T B field
-  Fundamental frequency
-      for 2 mm Al bond ~20 kHz
- 	Lorentz force was the reason!!

- Apply 100 mA current at ~20kHz

## Unanticipated Problems

- CDF central tracking chamber:
- Aging  resolved

- DØ LAr calorimeter:
- Welding induced noise  resolved

- Large missing energy
- Not new physics!

## “Trigger” Commissioning and Operations

- Tevatron: 2 million bunch collisions  100 events (per second)
- LHC: 40 million bunch collisions  200 events (per second)
- Making decisions extremely fast!  use limited information
- At hadron colliders, triggers determine Physics capability.

-  Trigger Paths
-  High pT electron (track + calorimeter)
-  High pT muon (track + calorimeter + muon)
-  High pT tau lepton (track + calorimeter)
-  Multi jets (track + silicon + calorimeter)
-  Other Paths for trigger validation
-  Trigger Paths for calibration (jet E, etc.)

- e.g. Top Quark Events

## Slide 21

## 2007 (Nov-Dec) LHC Data Samples at s = 0.9 TeV

- Start to commission triggers, detectors in real LHC environment.
- Observe a few W l,   , J/  ?

## LHC “Soft Collision” Meas. at s = 0.9 TeV

- At LHC design luminosity
- “each interesting physics event”
- contains 25 “soft” collisions.

- Single collision: Comparison of plateau’s between LHC and Tevatron will tell
- if detector performance, reconstruction tools and physics (simulation)
- are under control.

- Underlying Energy in jet events

## 2008 LHC Data Samples at 14 TeV (0.1 - 1 fb-1) 

| Sample | LHC events | Tevatron events |
| --- | --- | --- |
| W   | 106 - 107 | 106 |
| Z   | 105 - 106 | 105 |
| tt  Wb Wb   + X | 104 - 105 | 104 |
| QCD jets with pT > 1 TeV | 103 - 104 | - |

-  Understand and calibrate detectors
_*in situ using well-known physics samples *_
-  Measure Standard Model physics
-  W, Z, tt, QCD jets ...
-  omnipresent backgrounds to New Physics

## 2008 LHC Data Samples at 14 TeV

- Understanding detector and physics with top quark events.

- Compare this peak to
- Tevatron top mass measurement.

## Tevatron - LHC Physics Connection

- Origin of Mass
- Unification
- New Forces
- New Fermions
- ......
- The Unknowns

## that gives mass to particles 

- There might be something (new particle?!) in the universe
- that gives mass to particles

- Something in the universe

- Higgs Particles

- M ∞ coupling strength to Higgs

- Nothing in the universe

## Tevatron: Improve Higgs Mass Pred. via Quantum Corrections

- Current precision measurements
- indicate Higgs is light (<166 GeV),
- where Tevatron sensitivity is best!

-    Searches for Higgs with mass < 200 GeV/c2

- 68% CL

- mtopTevatron = 171.4 ± 2.1 GeV!

## Tevatron: Improve Higgs Mass Pred. via Quantum Corrections

-    Searches for Higgs with mass < 200 GeV/c2

- LHC: Designed to discover Higgs with Mhiggs = 100 ~ 800 GeV

- Will the Tevatron’s prediction agree with what LHC sees?

- Current precision measurements
- indicate Higgs is light (<166 GeV),
- where Tevatron sensitivity is best!

## Validating Monte Carlo Generators with Tevatron

- very important for LHC to reach the discovery quickly.

- M (GeV/c2)                                                          M (GeV/c2)

## Supersymmetric Extensions of SM (SUSY)

- e+        e-

- superparticle

- ~

- e

- spin 1/2        spin 0
-    Me ≠ Me

- Symmetry between
- fermions (matter) and bosons (forces)
- “Undiscovered new symmetry”

- SUSY solves Standard Model problems:
- Higgs mass calculation
- Unification
- SUSY provides a candidate particle for Dark Matter.
- Laws of Nature will be much more elegant at high energy.

- ~

- e          e

## Higgs in SUSY Models

- Higher precision MW and Mtop measurements enable to distinguish
- between SM, Light vs. Heavy SUSY

- LHC - the best place to discover Higgs!
- Tevatron can reach light Higgs
- at large tan
- (favored by precision measurements)

## The Higgs is Different!

- All the matter particles are spin-1/2 fermions.
- All the force carriers are spin-1 bosons.
- Higgs particles are spin-0 bosons.
- The Higgs is neither matter nor force;
- The Higgs is just different.
- This would be the first fundamental scalar ever discovered.

## If we discover a “Higgs-like” particle,

- is it alone responsible for giving mass to W, Z, fermions?
- The Higgs field is thought to fill the entire universe.
- Could give some handle of dark energy(scalar field)?
- The Higgs is a very powerful probe of new physics.
- Experimenters must precisely measure
- the properties of the Higgs particle
- without invoking theoretical assumptions.
-  Hadron collider(s) will discover the Higgs.ILC will use the Higgsas a window viewing the unknown.

## Unification

- that there was just one force after the Big Bang.
- As the universe cooled down,
- the single force split into the four that we know today.

## Slide 36

## Slide 37

## Slide 38

## Supersymmetric Extension of SM

- LHC is a fantastic place to discover SUSY partners!
- But Tevatron can reach some if they are light.

## Understanding Missing Energy

- ETmiss spectrum contaminated
- by cosmics, beam-halo,
- machine/detector problems, etc.

- e.g. SUSY at Tev scale

## Supersymmetric Extension of SM

- Why might Tevatron do physics that could be challenging at LHC?
-  Backgrounds: lower, different
-  Triggering might be hard
- Super partner of top quark (stop)
-  Might be light - favored by some scenarios (hep-ph/0403224)
-  This could be challenging
-    at both Tevatron and LHC
-  Backgrounds and triggering

- Neutralino Mass [GeV/c2]

- Scalar top Mass [GeV/c2]

- Jet + missing ET Trigger

- Tevatron ~300pb-1

## Ruling Out New Physics Models

- Many SUSY models affect
- significantly the rate that Bs particles
-  change into their anti-particles: ms
-  decay: Br(Bs  )

- Br(Bs  ) < 1.0 x 10-7 (CDF,1 fb-1), 3.7 x 10-7 (DØ, 300 pb-1)

- DØ: ms = 17 - 21 ps-1 at 90%CL (hep-ex/0603029) PRL
- CDF: ms = 17.31 +0.33-0.18 ± 0.07 ps-1 (hep-ex/0606027) PRL
- (agreeing well with SM)

- Already puts stringent limits on SUSY models.
- There is little room left for generic supersymmetry models that
- produce large new flavor-changing effects.

## Unifying gravity to the other 3 is accomplished by String theory.

- String theory predicts extra hidden dimensions in space
- beyond the three we sense daily.
- Can we observe or feel them? too small?
- Other models predict large extra dimensions:
- large enough to observe up to multi TeV scale.
- Tevatron up to ~2 TeV - LHC up to ~10 TeV

## The Unknowns!!

## Slide 45

## LHC Physics Center

**LHC**

**Tevatron**