# Presentation: 840408

## Snapshot of 

- Snapshot of
- Tevatron collider
- CDF detector
- DØ detector
- &
- First Run II results

- The Startup of Run II

## Tevatron Complex

**Main injector (150 GeV proton**
**storage ring) replaces main ring**
**New permanent magnet storage**
**ring for pbar accumulation (under**
**commissioning)**
**Increased center-of-mass energy **
**(1.8 ******** 1.96 TeV)**
**More bunches**
**(6 ********36, 396 ns crossing time)**
**Higher luminosity**
**Run 2 goal: 3 - 4E32 cm****-2**** s****-1**
**Run 2 maximum: 4.1E31 cm****-2 ****s****-1**
**     ****(to date)**
**Run 1 maximum: 2.4E31 cm****-2**** s****-1**

- New for Run II:

## Integrated Luminosity

## Peak Luminosity

## Luminosity Goals

- Short term

- >200 pb-1 by Sept. 2003

## Short-Term Plan

-  Accumulator bands 2&3 equalizers (5/2003)
-  AP3 beamline (6/2003)
-  Main injector longitudinal dampers (7/2003)
-  F0 Lambertson lamination shielding (summer shutdown)
-  Stacking upgrade
-  ......
-  Operation reliability improvement

- No silver bullet, a number of projects are being worked on...

- A six week shutdown starting late July for
- Recycler vacuum, electron-cooling construction, A0 modification,
- Tevatron collimator, ...

## Long-Term Goal

**Luminosity limitations:**
** ****pbar rate (~x5)**
** ****protons on target (x2)**
** ****pbar acceptance increase (x2-2.5**)
-  ......
-  **several small improvements (~x2)**

**Phased upgrades**
**while operating and**
**increasing luminosity**
**Limit shutdowns:**
** ****< 6 weeks per summer**
** ****~ 6 months for detector**
**  ****upgrade**

**Dropped:**
** ****132 ns operation**
** ****pbar recycling from Tevatron**

## CDFII Detector

- Retained from Run I
- Solenoid (1.4 Tesla)
- Central calorimeters
- Central muon detectors

- New in Run II
- Tracking system
- Silicon vertex detector (SVXII)
- Intermediate silicon layers
- Central outer tracker (COT)
- End plug calorimeter
- Intermediate muon detectors
- Time of flight system
- Front-end electronics
- Trigger system
- DAQ system

## Trigger and DAQ

- Data on tape:
- ~ 160+ pb-1
- (including commissioning data)

## Track and Vertex Triggers

- XFT:
- uses COT axial to find
- high pT tracks at L1

## Tracker Performance

- pT/pT = 0.13% pT (GeV/c)

- Power of Bl2 (~2 T m2)

## DØ Run II Detector

- New for Run II
- Magnetic tracker
- 2 Tesla solenoid
- Silicon microvertex tracker
- Scintillating fiber tracker
- Preshower detectors
- Forward muon detector
- Forward proton detector
- Front-end electronics
- Trigger and DAQ

- Retained from Run I
- LrAr calorimeter
- Central muon detector
- Muon toroid

## Trigger and DAQ

- Track and vertex triggers
- integration underway

## Vertexing Performance

- ~91% channels alive

- Silicon Microvertex Detector (SMT)

## Tracking Performance

- Bl2 ~ 0.5 T m2

## Many Preliminary Results

- Top quark physics
- Re-discovered the top quark,
- preliminary studies on properties, ...
- Electroweak
- W/Z productions, di-boson production,
- e+e- forward-backward asymmetry, ...
- New phenomena searches
- Higgs bosons, supersymmetry, leptoquark,
- large extra dimensions, Z’, ...
- Heavy flavor
- resonance reconstructions, masses, lifetimes,
- branching fractions, rare decays, ...
- QCD
- jet structure, inclusive jet cross section,
- dijet mass distribution, ...

**Please see the talks by M. Bishai, G. Borissov, C. Gerber, G. Veramendi for details**

## W/Z Production

- Ideal for calibration and
- precision measurements
-  Simple event topologies
-  Easy trigger and identification
-  High rate and small background

- Standard candle for high pT

## W/Z Cross Section

- C. R. Hamberg, W.L. van Neerven and T. Matsuura, Nucl. Phys. B359 (1991) 343

## Tau Identification

- Benefits and Challenges:
- The “missing” charged lepton
- Important for Higgs and supersymmetry searches
- Large backgrounds from jets, difficult to identify
- Learning from clean processes W, Zlh

## Top Quark Physics

- Production/Decay

## Top Pair Cross Section

| luminosity | dilepton | lepton+jets |
| --- | --- | --- |
| CDF | 79 pb-1 | 57.5 pb-1 |
| DØ | 33-48 pb-1 | 40-50 pb-1 |

- DØ Run II Preliminary

## First Look at mtop 

- CDF made a preliminary
- measurement of the top
- quark mass using the
- likelihood method

- (without using b-tagging information)

## Large Extra Dimensions

- DØ has searched for LED in
- diem (~50 pb-1) and
- dimuon (~30 pb-1) final state
- The existence of LED will modify
- both mass and angular distributions

## Slide 24

## Inclusive Jets Production

- Both CDF and DØ have shown preliminary results on inclusive jet
- cross section. The results agree well with theoretical predictions.

- The errors are dominated by
- jet energy scale uncertainty

## Dijet Mass Distribution

-  Dijet mass distribution is a tool for QCD test and
-    is also sensitive to high mass resonances.
-  Both CDF and DØ have measured dijet cross section
-    in Run II. The distributions agree well with the expectations.

## Heavy Flavor at CDF

- Huge cross sections, lots of particles, many topics, ...

## Heavy Flavor at DØ

- New in the game, but is catching up quickly...

- Expect a lot more for the summer...

## Run II Physics Program

- Each gain in luminosity
- yields a significant
- increase in physics reach
- and lays the foundation
- for the next step.
- We are producing interesting
- physics now and look forward
- to new challenges and
- opportunities in the future

- It is a program!

- Jianming Qian, University of Michigan

## Summary

-  Collider
-  Tevatron is a complex and old machine, it takes time
-  Started slower than we’d like, but making progress
-  Expect to deliver well over 200 pb-1 this year

- Slow start...

- Strong finish !

-  Detector
-  Both CDF and DØ detectors are working well
-  Both are taking physics data with high efficiencies

-  Physics
-  Impressive first results, harbinger of broader physics potential
-  Expect results from data samples of 100+ pb-1 this summer
-  Many measurements will supercede those of Run I