# Presentation: 132809

## Recent Physics Results 

***Evelyn J. Thomson***
***The Ohio State University***

**B physics**
**B****s**** and ****Λ****b**** properties**
**B****s**** mixing**
**Electroweak physics**
**W width**
**Z FB asymmetry**
**Top physics**
**Top production**
**Top mass**
**QCD**** **
**Inclusive jet production**
**Searches for new physics**
**Extra dimensions**
**SUSY**
**Leptoquarks **
**Rare decays**

_**Recent Physics Results **_
_**from CDF and D0**_

## Performance of Fermilab Tevatron

**Current Initial Luminosity**
**~40x10****30**** cm****-2****s****-1****    **
**Integrated Luminosity**
**~200 pb****-1**** this year**
**Run II Goals **
**>2000 pb****-1**** in 2007**
**>4000 pb****-1**** in 2009**

**Best**
**Run I **
**110pb****-1**

**Run I→Run II**
**E****CM****=1.8****→****1.96 TeV**
**T****bunch****=3500→396 ns**

_**Performance of Fermilab Tevatron**_

## CDF and D0 status: Run II > Run I! 

**CDF since June 2001**
**Delivered ~ 300 pb****-1**
**Recorded ~ 230 pb****-1**
**Summer 2003 prelim. **
**results ~ 140 pb****-1**

**Integrated luminosity (pb****-1****)**

_**CDF and D0 status: **__**Run II > Run I!**_** **

**D0 since April 2002**
**Delivered ~ 240 pb****-1**
**Recorded ~ 180 pb****-1**
**Summer 2003 prelim. **
**results ~ 130 pb****-1 **

## “Physics at a hadron collider...

| Process | Cross-section | Event Rate |
| --- | --- | --- |
| Inelastic pp | 60 mb | 6 MHz |
| pp→bb (b pT>6 GeV, |η|<1) | 10 μb | 1 kHz |
| pp→WX→lνX | 5 nb | 0.4 Hz |
| pp→ZX→llX | 0.5 nb | 0.04 Hz |
| pp→tt→WWbb→lνbbX | 2 pb | 0.0002 Hz |
| pp→WH→lνbb (if MH=120GeV) | 15 fb | 0.0000015 Hz |

**Assume ****L ****=100x10****30**** cm****-2****s****-1****, ****l=electron or muon**

**...****is like drinking from a fire-hose!”**
**...****is like panning for gold!”**
**...****is all about the trigger!’**

**Examine each pp collision (1.7 MHz)**
**Select few interesting events (<70 Hz)**
**Store for further offline analysis**

**High p****T**** lepton**
**High E****T**** jet, photon**
**High Missing E****T**** (MET)**
**Displaced hadrons from bottom and charm decay**

**Keep 1 out of 25,000 **

_**“**__**Physics at a hadron collider...**_

## Three level trigger - CDF

_**Three level trigger - CDF**_

## CDF Level 1 Track Trigger

**Heart of CDF Run II trigger**
**L1 tracks p****T****>1.5GeV every 132ns**
**Efficiency=96****% ****σ****(****Φ****)=5mr**** **
**σ****(p****T****)=(1.74 p****T****)%**
**L1 electron = L1 track + EM cluster**
**L1 muon    =  L1 track + muon stub**
**L1 high p****T**** lepton triggers for W/Z**
**L1 low p****T**** lepton/track triggers for B**

**Low p****T**** di-muon trigger:**
**2 L1 muons p****T****>1.5 GeV**
**Collect J/****Ψ****’s for calibration and B physics**

_**CDF Level 1 Track Trigger**_

## CDF Level 2 Silicon Vertex Trigger

**Exploit long b, c  lifetimes in Trigger!**
**L1 track + Si hits = Impact parameter @L2 **
**A first at a hadron collider!**
**CDF is a charm/ B Factory!**

***Lepton (e, ******μ******) + displaced track trigger***
**Lepton:p****T****>4 GeV**
**Track: p****T****>2 GeV, d****0****>120 ****μ****m**
**Semi-leptonic B decays (B****→****l****ν****X****)**** **
***Displaced two track trigger***
**Tracks: p****T****>2 GeV, d****0****>120 ****μ****m**
**Σ****p****T****>5.5 GeV**
**Fully hadronic B decays (B→hh’, B****s****→D****s****π****, D→K****π**** ...)**

_**CDF Level 2 Silicon Vertex Trigger**_

## CDF Momentum Scale Calibration

**Essential for**
**Mass differences**
**Mass measurements**

**Use 500k J/****Ψ→****μ****+****μ****-**
**Measure detector material**
**to remove p****T**** dependence**
**Energy loss corrections**
**Compare to PDG ****J/****Ψ**** mass**
**B field calibration**

**Using calibration from J/****Ψ****, test with**
**Low momentum (****π****):    K****s**** ****→π****+**** π****-**
**High statistics (K, ****π****):  D****0****→****K****+**** π****-**
**High momentum (****μ****):   ********→ μ****+**** μ****-**

_**CDF Momentum Scale Calibration**_

## D Meson Mass Difference

**Displaced two track trigger**

**Common final decay state**
**Almost identical kinematics**
**Many systematics cancel**

_**D Meson Mass Difference**_

## Prompt Charm Meson Cross-section

**First measurement at a hadron collider**
**Above theory as for  B mesons**
**Test NLO QCD **

**Submitted to PRL (hep-ex/0307080)**

**(Rapidity<1)**

## B Physics

**B****s**** meson and ****Λ****b**** baryon unique to Tevatron now**
**(Not produced at BaBar or Belle)**

**B****s**** meson properties:**
**Mass**
**Lifetime**
**Δ****m****s**** frequency**
**ΔΓ****s**
**CP violation**
**CKM angle ****γ**** **
**Λ****b**** baryon properties:**
**Mass**
**Lifetime**
**CP violation**
**Test of HQE**

_**B Physics**_

## Bs Meson Mass and Lifetime

**B****s**** mass**** – PDG 5369.6 ± 2.4 MeV/c****2**
**CDF 5365.5 ± 1.3****(stat)**** ± 0.9****(sys)**** MeV/c****2**
**D0 5360 ± 5 MeV/c****2**

**B****s****→****J/****ψ**** ****Φ****  ****with J/****ψ→μ****+****μ****-**** and ****Φ→****K****+****K****-**** **
**B****+****→ J/****Ψ****K****+****, B****0**** ****→J/****Ψ****K*****0  ****check technique, systematics **

**Mass J/****ψ**** ****Φ**** (GeV) **

**Mass J/****ψ**** ****Φ**** (GeV) **

**ct (cm)**

_**B**__**s**__** Meson **__**Mass and Lifetime**_

**Future:**
** ****Search for CP violation and measure ****β****s**
**Compare to lifetime from B****s****→ l****ν****D****s**** and extract ****ΔΓ****s**

## Λb mass and lifetime

**Λ****b****  mass**** – PDG 5624 ****± 9 MeV/****c****2**
**CDF 5620.4 ± 1.6****(stat)**** ± 1.2****(sys)**** MeV/c****2**
**D0 in progress**

**Check technique systematics**

**First lifetime from fully reconstructed ****Λ****b**** decay!**

**Λ****b****→****J/****ΨΛ**** **
**with ****J/****ψ→μ****+****μ****- **** and **** ****Λ →****p****π**

**Mass J/****ψ****Λ**** (GeV) **

**Mass J/****ψ****Λ**** (GeV) **

**ct (cm) **

_**Λ**__**b**__** mass and lifetime**_

## In Future: Particle Identification!

**Λ****b****→****Λ****c****π**** with ****Λ****c****→pK****π**
**Plagued with reflections!**

**Add dE/dx particle id**
**Reduce reflection by ~3**
**Only lose ~15% signal**

_**In Future: Particle Identification!**_

## B lifetime ratios

**Why do we care about B lifetimes, especially ****Λ****b****?****  **
**Important Test of Heavy Quark Expansion**

_**B lifetime ratios**_

## Bs→Dsπ Relative Yield

**First observation!**
**Fully reconstructed hadronic final state**
**Two track trigger essential**
**Production rate understood**
**Ratio of branching ratios cancels most systematics**

**Golden mode for B****s**** mixing**** **
**In progress:**
**Flavour tagging (****ε****D****2****)**
**Exquisite ct resolution**

_**B**__**s**__**→**__**D**__**s**__**π**__** Relative Yield**_

## Towards Bs mixing

**@95% C.L.  ****Δ****m****s ****≥ ****14.4 ps****-1**
***At least 30 times faster***
***than B******d****** mixing ***
***Δ******m******d******=0.502 ± 0.006 ps******-1***
***Will need ******exquisite ***
***proper time resolution!***
***Minimise error on p******T***
***with fully reconstructed***
***decays B******s******→D******s ******π****** ***
***CDF ~ 60 fs (45 fs with L00)***
***    ******D0 ~ 75 fs***

_**Towards B**__**s**__** mixing**_

**Flavour tagging **
**Need everything for ****ε****D****2****~10%**
**ε**** = tag efficiency**
**D = tag correct (dilution)**
**Yield – need ~1000 events**
**CDF yield ~50 events in 65 pb****-1**
**Below expectations...**
**...****but careful with your abacus!**
**Silicon coverage much improved**
**Trigger with majority logic**
**Add more decay modes**
**For 2 fb****-1****, 5****σ**** sensitivity up to**
**  ****x****s ****= 63 (S/B = 2/1)      ****x****s****= ****Δ****m****s****τ****(B****s****)**
**  ****x****s**** = 53 (S/B = 1/2)**

**B****s**** ******** D****s********, ****D****s ******** ******** ******** **
**         ****D****s**** ******** ********, ****K*K, ******

## Two-Body Charmless B decays

**Raw fit results**
**N(B****0****→K****π****)= 148 ****± ****17**
**N(B****0****→****ππ****)=   39 ± 14**
**N(B****s****→****KK)=   90 ± 17 First observation!**
**N(B****s****→K****π****)=     3 ± 11**

**Future: CKM angle ****γ**

**B****→****h****+****h****-**** observed at CDF**
**About 280 candidates (S:N=2:1)**
**Peak is a mix of B****0****,B****s**** ****→**** ****ππ****, ****π****K, KK**
**Statistical separation with dE/dx and kinematics**

_**Two-Body Charmless B decays**_

## Disentangling Charmless B decays

_**Disentangling Charmless B decays**_

## Electroweak Physics

**Standard Candles!**
**W/Z cross-sections**
**Ratio ->  W width**
**W mass**
**W charge Asymmetry**
**Z FB Asymmetry**
**WW, WZ, ZZ, W****γ****, Z****γ**

**Trigger on leptonic decays**
**Clean low bkg event signatures**
**W: 1 high p****T**** lepton + large MET**
**Z: 2 high p****T**** leptons**
**BR~11% per mode for W ****→**** ****l ****ν**** **
**BR~3% per mode for Z****→**** ****l****+****l****-**** **

_**Electroweak Physics**_

## σ(W) x BR(W→ lν)

|  | CDF | CDF (all: 72pb-1) | D0 | D0 (e: 42pb-1; μ: 17pb-1) |
| --- | --- | --- | --- | --- |
| l | Events | σ(W) x BR(W→ lν) (nb) | Events | σ(W) x BR(W→ lν) (nb) |
| e | 38625 | 2.64 ± 0.01 ± 0.09 ± 0.16 | 27370 | 2.84 ± 0.02 ± 0.13 ± 0.28 |
| μ | 21599 | 2.64 ± 0.02 ± 0.12 ± 0.16 | 7352 | 3.23 ± 0.13 ± 0.10 ± 0.32 |
| τ | 2346 | 2.62 ± 0.07 ± 0.21 ± 0.16 | - | result ± stat ± sys ± lum |

**E****T****>25GeV, MET>25 GeV**
**CDF |****η****|<1.0,    D0 |****η****|<1.1**

**p****T****>20GeV, MET>20 GeV**
**CDF |****η****|<0.6,    D0 |****η****|<1.6**

**Theory prediction 2.731 ****± 0.002 nb NNLO *****Stirling et al., Phys Lett B531 (2002) ****** ***

_**σ**__**(W) x BR(W→**__** **__**l**__**ν**__**)**_

## σ(Z) x BR(Z→ l+l-)

|  | CDF | CDF (all: 72pb-1) | D0 | D0 (e: 42pb-1; μ: 32pb-1) |
| --- | --- | --- | --- | --- |
| l | Events | σ(Z) x BR(Z→ ll) (nb) | Events | σ(Z) x BR(Z→ ll) (nb) |
| e | 1830 | 0.267 ± 0.006 ± 0.015 ± 0.016 | 1139 | 0.275 ± 0.009 ± 0.009 ± 0.028 |
| μ | 1631 | 0.246 ± 0.006 ± 0.012 ± 0.015 | 1585 | 0.264 ± 0.007 ± 0.017 ± 0.026 |

**E****T****>25GeV**
**CDF |****η****|<1.0,   D0 |****η****|<1.1**

**CDF p****T****>20GeV,   D0 p****T****>15GeV**
**CDF |****η****|<0.6,         D0 |****η****|<1.8**

**Theory prediction 0.252 ****± 0.009 nb NNLO *****Stirling et al., Phys. Lett. B531 (2002) ****** ***

_**σ**__**(Z) x BR(Z→**__** **__**l**__**+**__**l**__**-**__**)**_

## W and Z cross-sections vs ECM

***Theory: R Hamberg, WL van Neerven and T Matsuura,***
*** ******Nucl. Phys. B359 (1991) 343 CTEQ4M PDF***

_**W and Z cross-sections vs E**__**CM**_

## Indirect Measurement of W Width

**W, Z cross-sections systematics limited**
**Most of systematics cancel in ratio R**
**Indirect measurement of ****W width**

|  | R |
| --- | --- |
| CDF e |   9.88 ± 0.24 ± 0.44  |
| CDF μ | 10.69 ± 0.28 ± 0.31 |
| D0    e | 10.34 ± 0.35 ± 0.49 |
| Combined | 10.36 ± 0.16 ± 0.27 |

**Γ****(W)**** – PDG ****2.118 ****± ****0.042 GeV**
**Run II           2.181 ± 0.074 GeV**

_**Indirect Measurement of W Width**_

## Forward-Backward Asymmetry

**High mass reach unique to Tevatron**
**Probe Z-****γ***** interference**
**Complements direct Z’ search**
**Result agrees with SM**

**Zoom into high stats**
**Z pole region **

**Electron |****η****|<3**
**Forward **
**calorimeter  **
**crucial!**

_**Forward-Backward Asymmetry**_

## Top Physics

**Top discovered by CDF and D0 in 1995**
**Very heavy!  Top mass = 174.3 ± 5.1 GeV **
**Only ~30 events per experiment**
**!!!Want more top events to study properties!!!**
**Run II ****σ**** 30% higher at √s=1.96 TeV**

***Similar mass to Tungsten***
***Atomic # 74***
***35 times heavier ***
***than b quark***

_**Top Physics**_

## Top quarks produced in pairs via
strong interaction: 85% qq, 15% gg

**Top quarks produced in pairs**** via**
**strong interaction: 85% qq, 15% gg**

**Top quark heavy => decays very fast!**
**	****Γ****(t****→****bW)~1.5 GeV, ****τ****top****~4x10****-25****s**
**	****     ****c.f. ****Λ****QCD****~100 MeV, ****Λ****-1****~10****-23****s**
**Too fast for hadronisation!**
**No top mesons or baryons**
**Decay products know top spin**

**3 characteristic event signatures from WW decay**
**Dilepton****: BR small but pure**
***2 high p******T****** leptons, high MET******, ≥2 jets***
**Lepton+Jets****: BR larger but less pure**
***1 high p******T****** lepton, high MET, ≥4 jets (1 b-tag)***
**All-hadronic****: BR largest but huge QCD bkg**
***≥***** *****6 jets (2 b-tags)***

_**Top Quark Production & Decay**_

## Top Pair Production cross-section

**Why is it interesting?**
**Re-discover top in Run II**
**Does cross-section increase?**
**Develop selections and **
**background estimates for other**
**top analyses**
**All measurements so far**
**are counting experiments**

_**Top Pair Production cross-section**_

## Top cross-section: Dilepton

| CDF: 72 pb-1 | ee | μμ | eμ | Total ll |
| --- | --- | --- | --- | --- |
| Background | 0.10 ± 0.06 | 0.09 ± 0.05 | 0.10 ± 0.04 | 0.30 ± 0.12 |
| tt→lνlνbb | 0.47 ± 0.05 | 0.59 ± 0.07 | 1.44 ± 0.16 | 2.50 ± 0.30 |
| SM expectation | 0.57 ± 0.08 | 0.68 ± 0.09 | 1.54 ± 0.17 | 2.80 ± 0.32 |
| Data | 1 | 1 | 3 | 5 |

| D0 | ee: 107 pb-1 | μμ: 90 pb-1 | eμ: 97 pb-1 | Total ll |
| --- | --- | --- | --- | --- |
| Background | 0.58 ± 0.51 | 0.70 ± 0.44 | 0.60 ± 0.42 | 1.88 ± 0.79 |
| tt→lνlνbb | 0.63 ± 0.10 | 0.46 ± 0.10 | 1.73 ± 0.26 | 2.81 ± 0.30 |
| SM expectation | 1.21 ± 0.52 | 1.16 ± 0.45 | 2.33 ± 0.49 | 4.69 ± 0.64 |
| Data | 2 | 0 | 3 | 5 |

**CDF ****ll**
**S:B = 8:1**
**Very pure!**

***2 high p******T****** leptons, high MET, ≥2 jets***

_**Top cross-section: Dilepton**_

**New! Lepton + isolated track (126 pb****-1****)**

**D0 ****ll**
**S:B = 3:2**

## Top cross-section: Lepton + Jets

**D0 CSIP**

**D0 SVX**

**CDF SVX**

***1 high p******T****** lepton, high MET, ≥3 jets, 1 b-tag***
**SVX:**** secondary vertex  **
**  ****CDF L****xy  ****> 3****σ****(L****xy****)  D0 L****xy ****> 5****σ****(L****xy****)**
**CSIP: ****count tracks with significant d****0**
**  ≥****2 tracks with d****0 ****> 3****σ****(d****0****)**
**  ≥****3 tracks with d****0 ****> 2****σ****(d****0****)**
**45-55% efficiency for 1 b-tag in tt MC**

**Use 1, 2 jet events to check bkg model**
**Look for excess in ≥3 jet region**

_**Top cross-section: Lepton + Jets**_

**45pb****-1**

**45pb****-1**

## D0 Run II Electron + Jets Candidate

**Event is b-tagged by  both SVX and CSIP (run 169923 event 16396718)**
**4 jets**
**Electron p****T**** = 27 GeV**
**Jet p****T**** = 51, 36, 30, 53 GeV **
**Missing E****T**** = 58 GeV**
**H****T**** = 207 GeV**
**Aplanarity = 0.11**

**Primary vertex**
**N****track**** = 17**
**z = ********4.6 cm**

_**D0 Run II Electron + Jets Candidate**_

## Top cross-section: Lepton + Jets

**CDF II preliminary 108 pb****-1**

_**Data**_
**108 pb****-1**
**45 pb****-1**
**45 pb****-1**
**90 pb****-1**

## Top Quark Mass and the Standard Model

**Top strongly correlated with Higgs**
**5 GeV shift in m****top**** => 37% shift in m****H **
***	******            ******(M. Gruenewald DESY-Zeuthen ’03)***
**Top mass measurement crucial**
**to indirect prediction from SM fit! **
**Run II goal: m****top**** error < 3 GeV**

**Why is it interesting?**
**Over-constrains SM**
**Confronts indirect predictions**
**with direct measurements**
**See good agreement**
**Both prefer lighter Higgs**

**Top mass (GeV)**

**W mass (GeV)**

**Higgs mass (GeV)**

**68% CL**

_**Top Quark Mass and the Standard Model**_

## CDF Run II Top Mass: Lepton + Jets

** ****All events carry same weight**
** ****Fit to shapes from MC**

_**CDF Run II Top Mass: Lepton + Jets**_

| Source | Systematic (GeV/c2) |
| --- | --- |
| Jets | 6.2 |
| ISR/FSR | 2.6 |
| PDF | 2.0 |
| Other MC modeling | 1.0 |
| Generators | 0.6 |
| Bkgd shape | 0.5 |
| b-tag | 0.1 |
| Total | 7.1 GeV |

***1 high p******T****** lepton, high MET, ≥3 jets, 1 b-tag***
***4******th****** jet E******T******>8 GeV (usually 15 GeV)***
***22 events, expect 6.5 ± 2.0 from bkg***

**CDF Run II preliminary 108 pb****-1**

## Reconstructed event-by-event top mass

**     ****M****l****υ****=M****W****, M****jj****=M****W****, M****t1****=M****t2, ****p****T**** balance**
**4 jets = 12 possible jet-parton combinations**
**	****x 2 solutions for neutrino p****z**
**!!!Use b-tagging to reduce permutations!!!**
**Choose combination with lowest ****χ****2**

_**Reconstructed event-by-event top mass**_

## Improved D0 Run I Top Mass

**Uses event probabilities**
**- Full set of event observables**
** ****Better measured events **
**  ****carry more weight**
**Reduces background**
**91 original candidates**
**77 after exactly 4 jets**
**22**** after Pbkg<-11**

**M****top****=180.1 ****± 3.6 ± 4.0 GeV**

**Old stat error was 5.6 GeV!**
**Like 2.4 increase in statistics!**

_**Improved D0 Run I Top Mass**_

## Top Mass – Expected Statistical Errors

_**Top Mass – Expected Statistical Errors**_

**D0 Run I (125 pb****-1****)**
**Preliminary**
**Expected 5.4 GeV**
**Observed 3.6 GeV**

**CDF Run II (108 pb****-1****)**
**Preliminary**
**Expected 8.8 GeV**
**Observed +12.7, -9.4 GeV**

**Expected stat. error (GeV)**

**Expected stat. error (GeV)**

**Data**
**-ve**

**Data**
**+ve**

**Data**

**Observed errors**
**consistent with expectations**

## QCD -  Inclusive Jet Production

**Systematics dominated by **
**Jet Energy Scale...to be reduced**

**Theoretical error dominated **
**by  PDF’s  (gluon at high-x)**

**Agreement within uncertainties**

**Why should you care?  Mother of all backgrounds!**
**Jet cross-section – ****sensitive to gluon distribution in proton**
**Better predictions of many new physics processes at high energies**

**Highest E****T**** jets ever! **
**8 orders of magnitude!**

_**QCD -  Inclusive Jet Production**_

## QCD – Dijet cross-section

**Cross-section well reproduced by NLO theory over 6 orders of magnitude**

**Systematics dominated by **
**Jet Energy Scale**

_**QCD – Dijet cross-section**_

## Searches for New Physics

**Why?  Standard Model is incomplete!****  **
**Why M****EW**** << M****Pl****?**
**How to achieve grand unification?**
**How to include gravity?**
**What explains proliferation of quarks and leptons?**
**What determines their mixings?**
**More general theories make predictions that can be tested at the Tevatron**** **

_**Searches for New Physics**_

## Searches for New Physics

**likely place to directly discover a new particle or force**

**Search for Extra Dimensions, Z’**
**Study of high E****T**** tails**
**Search for SUSY**
**Jets + MET**
**Photons + MET**
**Trileptons**
**Search for Leptoquarks**
**First generation eejj**
**Second generation ****μμ****jj**
**All generations ****νν****jj**
**Search for Rare Decays**
**D****0****→****μ****+****μ****-**
**B****s****→****μ****+****μ****-**

**What is dark matter?**
**SUSY LSP? **
**Extra dimensions?**
**Tevatron can put limits on models**

- WMAP, astro-ph/0302207

_**Searches for New Physics**_

## Extra Dimensions Overview

**n “large” extra dimensions of size**
**n=1 R~10****8**** km – excluded!**
**n=2 R~1 mm ~ tabletop realm**
**n****≥****3 R≤3 nm - collider realm**

_**Randall-Sundrum Model**_
**One “small” extra dimension**
**warped by factor **
**Spin-2 resonance**
**Graviton mass**
**Coupling k/M****Pl**

**SM particles confined to 4 dimensions **
**Gravity propagates in extra dimensions**
**Solves the hierarchy problem!**
**Can explain dark matter!**

_**Experimental signatures**_
**Virtual graviton exchange**** modifies**
**fermion/boson pair production**

**Direct graviton emission**** **
**Jets + MET**
**Photon + MET**

_**Extra Dimensions Overview**_

## Extra Dimensions – ADD Model

| 95% C.L.
MS (TeV) | GRW | HLZ 
n=2, 3, 7 | Hewett
λ=+1 |
| --- | --- | --- | --- |
| D0 diEM | 1.28 | 1.42, 1.52, 1.01 | 1.14 |
| D0 μμ | 0.88 | 1.05, 0.88, 0.70 | 0.79 |
| CDF diEM | - | - | 0.85 |

**ee and ****γγ****: 2 EM objects p****T****>25 GeV**

**Consistent with no signal**
**D0 now has world’s best limit!**
**Probe up to 2 TeV with 2 fb****-1**

**Virtual graviton exchange**
**Look for excess at**
**high dilepton or diphoton mass **

_**Extra Dimensions – ADD Model**_

## Extra Dimensions -  Randall-Sundrum Model

**Spin-2 graviton**
**Look for resonances in **
**dilepton mass**
**Consistent with no signal**

_**Extra Dimensions -  Randall-Sundrum Model**_

## Extra Gauge Bosons

**Predicted by many models **
**Look for resonance in dilepton mass**
**Consistent with no signal**

**~50pb****-1**

**D0 m(Z****′)> 719 GeV @ 95% C.L ~100pb****-1**
**World’s best limit**

**Probe up to 1 TeV with 2 fb****-1**

**CDF m(Z****′)> 665 GeV @ 95% C.L**
**Close to Run I 690 GeV**

_**Extra Gauge Bosons**_

## Dijet Resonances

**Sensitive to a variety of new physics**
**Probes highest energies**
**Axigluon mass > 1.1 TeV@95%C.L.**

_**Dijet Resonances**_

## Scalar Leptoquarks

**~100pb****-1**

**First generation LQ****1 ****LQ****1****→eejj**

**Second generation LQ****2 ****LQ****2****→****μμ****jj**

**All three generations LQ LQ→****νν****jj **
** ****Jets + MET**
**CDF M(LQ)>107 GeV @95%C.L. **

**D0 M(LQ****1****)>253 GeV @ 95% C.L.**
**CDF M(LQ****1****)>230GeV @ 95% C.L.**

**D0 M(LQ****2****)>186 GeV @ 95% C.L.**
**CDF in progress**

**Directly couple quarks to leptons**
**Predicted by Grand Unified Theories**

_**Scalar Leptoquarks**_

## SUSY – Search for Long-lived Stop

**Long-lived massive charged particles?**
**Move slowly **
**Measure time-of-flight!**
**Δ****TOF=TOF candidate – TOF at c**

**Consistent with no signal**
**m(stop)> 107 GeV @95% C.L.**
**LEP limit is 95 GeV**

**Selection**
**Tracks with p****T****>40 GeV**
**Δ****TOF>2.5 ns**
**Observe 7 events in 53pb****-1**
**Expect  2.9 ± 0.7****(stat)**** ± 3.1****(syst)**

_**SUSY – Search for Long-lived Stop**_

## SUSY – Sbottoms from Gluino Decays

**Gluino pair production**** cross-section large**
**Very distinctive signature of 4 b jets + MET**

**Selection**
**3 or more jets**
**MET> 50 GeV**
**Lepton veto**

| b-tag | Data | Expected
Background | Expected
Signal |
| --- | --- | --- | --- |
| Single | 4 | 5.6 ± 1.4 | 10.6 ± 1.7 |
| Double | 1 | 0.5 ± 0.1 | 4.4 ± 0.9 |

**Assume**

_**SUSY – Sbottoms from Gluino Decays**_

## SUSY Trileptons

**“****Golden” channel with low backgrounds**** but**
**Leptons are soft (p****T****<20 GeV)**
**tan****β****>8 most leptons are taus!**
**Need >300pb****-1**** to improve on LEP**

**Understanding soft electrons!**
**Two electrons p****T****>10 GeV**
**At least one electron p****T****<20 GeV**

**Understanding taus!**
**CDF has **
**tau (p****T****>5 GeV) and di-tau triggers**

_**SUSY Trileptons**_

## Search for Gauge Mediated SUSY

**Gaugino pair production and **
**LSP = gravitino NLSP= neutralino**
**Experimental signature ****γγ****+MET**
**Close to Run I limits**

_**Search for Gauge Mediated SUSY**_

## Rare Decays

**Search for FCNC B****s****→****μ****+****μ****-**
**CDF 1 candidate in B****s**** and B****d**** window**
**BR(B****s************) < 9.5E-7  @ 90% CL**
**	****       ****< 1.2E-6  @ 95% CL**
**BR(B****d************) < 2.5E-7  @ 90% CL**
**                    ****< 3.1E-7  @ 95% CL**

**SM BR(B****s****→****μ****+****μ****-****)~ 3.8x10****-9**
**Various SUSY models predict**
**enhancement by 10 to 1000**
**Recently interesting since**
**same SUSY models predict **
**deviations of (g-2)****μ**** **
***Exp: PRL 89 (2002) 101804,129903***
***Theory: PRL 87 (2001) 251804***

_**Rare Decays**_

**D0 3 candidates in B****s**** window**
**BR(B****s************) < 1.6E-6  @ 90% CL**

**World’s best limits for B****s**
**May catch up to BaBar/Belle for B****d**

## Rare Decays

**CDF**
**1 event in B****s**** and **
**B****d ****search window**
**Expected bkg **
**0.54 ********0.20 (for B****s****) **
**0.59 ********0.22 (for B****d****)**

_**Rare Decays**_

**D0**
**3 events in B****s**
**search window**
**Expected bkg **
**3.42 ********0.79 (for B****s****) **

## Search for the SM Higgs Boson

**In 50% of experiments**

**20****th**** century CDF/D0 sensitivity study still valid**
**21****st**** century CDF/D0 search will need:**
**Sophisticated techniques to improve sensitivity**
**Excellent understanding of backgrounds and systematics**
**Enough data!**

**LEP m****H****>114.4 GeV @95% CL**

## CDF and D0 are back!

** ****Displaced track trigger for B physics**
**B****s**** meson and ****Λ****b ****baryon**
**W and Z bosons**
**Top quark**
**Searches for new physics**
**In next few years**
**B****s**** mixing**
**Top quark mass error < 3 GeV**
**World’s best limits for searches...**
**...****or discovery of new physics!**

**CDF and D0 are back!**

_**Conclusions**_

## CDF Detector Upgrades

_**CDF Detector Upgrades**_

## D0 Detector Upgrades

**2.0 T magnetic field**
**Lever arm 52 cm**

**4 silicon layers+disks**
**Suited to limited space**
**2.8<r<10 cm**** **
**|****η****| ≤ 3.0, cos****θ****=0.993**

**Now! Sci-Fi tracks@L1**
**Next! Silicon tracks@L2 **
**5000/1000/50 Hz**

**8 layer Sci-Fi tracker |****η****|≤ 1.7**
**10<r<52 cm, 80k channels**
**VLPC’s at 9K, 85% QE**
**σ****(hit) ~ 100 ****μ****m**

**Pre-shower**
**Particle id**
**Energy**

**Some resolutions:**
**p****T**** ~ (2.0 **** 0.2 p****T****)%**
**J/****Ψ**** mass ~27 MeV**
**EM E ~ 15%/****√E**
**Had E ~ 80%/√E**
**d****0**** ~ 13+50/p****T**** ****μ****m**
**Primary vtx ~15 ****μ****m**
**Secondary vtx **
**r-****Φ**** ****~ 40 ****μ****m**
**r-z ~ 80 ****μ****m**

**μ**** coverage to**
**|****η****|****≤2.0**
**90% in phi**

_**D0 Detector Upgrades**_