•CDF Detector
•Drell-Yan & Signatures for New Physics
•Present Limits and Run II reaches
•First Run II Data
•Future Plans
Supervisor: Todd Huffman, Oxford UniversityAdvisor: Kaori Maeshima, FNAL
Presented work by Tracey Pratt, Oxford and Koji Ikado, Waseda University
By Tracey Pratt
April 02
High mass bump searches in Drell-Yan spectrum at CDF
CDF at Fermilab
CDF CDF
D0
Tevatron
Main Injector
pp collisions
CDF Run I and Run II overview
Run I consisted of Run 1a (88/89) and Run 2b (92-95)
In total 110pb-1 of data was collected
Centre of mass energy 1.8 TeV
Since the shutdown in 1996, the Tevatron and CDF have undergone major upgrades
Run II started in June 2001
Centre of mass energy 2 TeV
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Drell-Yan (DY)
Low background at high dilepton invariant massDistinctive signatures:
•two oppositely charged leptons produced
•have a high transverse momentum
•are isolated
•originate from a single interaction point
qq */ Z l+l-
p p
l+ l-
*/ Z
q q
New Physics Searches with DY
New Gauge Bosons (Z')
Extra Dimensions
Quark-lepton Compositeness
Technicolor (T , T )
Looking for deviations to the Standard Model at high invariant mass
Run I Drell-Yan (DY)
•AFB smaller than SM
• AFB dips beyond 200 GeV/c2
X 88/89 CDF Run 1 dileptons (ee+ 4pb-1)
o 92-95 CDF Run 1 dimuons (107.4pb-1)
Invariant Mass in GeV/c2
0 100 200 300 400
101
100
10-1
10-2
10-3
10-4
Z and
only
d2/dMdy
Run 1 Z' limitsset limits for Z' ll, with 110pb-1, in both dielectron and dimuon channels
CDF Run I (110pb-1), for MZ > 600 GeV/c2 (Z ).BR(Z ->ll) is 40 fb.
which excludes MZ with Standard Model coupling < 690 GeV/c2
(Phys. Rev. Lett.79: 2192-2197, 1997))
Run II Extrapolated limits
Extrapolating from Run I, with 2 fb-1, the predicted Z' mass reach could be extended to
900 GeV/c2 with s =1.8 TeV assuming Standard Model couplings
and to about
1000 GeV/c2 with s =2.0 TeV
Extra DimensionsADD model
***references
New parameters:
1. String Scale: Ms = MPl(4+n) 2. A Factor: ( = ±1)
RS model L.Randall and R.Sundrum, Phys. Rev. Lett. 83,3370 (1999), Phys. Rev. Lett. 83,4690 (1999)
New parameters:
1. First graviton excitation mass: m1
2. A Ratio: k/MPl
Graviton Exchange - modifies the rate and angular distribution of high-mass Drell-Yan events
ADD model and RS model limits
SM predictionQuantum Gravity Model for Ms valuesCDF results for dimuon samples
Effective Planck Scale lower limit (95% C.L.)0.9-1.5 TeV Run I1.3-2.5 TeV Run IIa, 1.7-3.5 TeV LHCRange corresponds to number of extra dimensions n=7-2. (hep-ph/9909218)
Mll (GeV)
RS model
10 -2
10 -4
10 –6
10 -8
200 400 600 800 1000 1200
d/dM (pb/GeV) 1
0.70.50.30.20.1
700 GeV KK graviton
Compactification scales R-1 (TeV) 0.9 Run 1 at 95% C.L., 1.2 Run II, 6.7 LHC(one large extra dimension) (hep-ph/9905311)
Run IK/MPl
Compositeness
Compositeness
Quark-lepton contact interaction was searched for in Run I in the dimuon and dielectron channels, by looking for an excess of dileptons compared to the Drell-Yan prediction.
Run Ib dielectron data set the limits on the compositeness scale to - > 3.8 TeV and + > 2.6 TeV. In Run II we expect to be able to explore up to limits of approximately 5 TeV.
(Where +/- corresponds to the constructive / destructive interference with the dominant up-quark contribution to the cross-section.)
(Phys. Rev. Lett.79: 2198-2203, 1997))
Run II
Run II officially began on March 1st 2001
Started taking “physics quality” data from June 2001
CDF Upgrade improvements for Drell-Yan measurements•Dielectron channel New plug calorimeter •Dimuon channel Increased muon chamber coverage Improved Dimuon Background Rejection in run II
Time-Of-Flight (ToF) Detector in CDF
216 scintillator bars located just outside the COT
Expected time resolution is 100 ps.
ToF Cosmic-Ray Rejection
~ 2L/c for CR dimuons ~ 0 for interaction dimuonsas for dielectrons
For high mass dimuon sample the
dominant background at high invariant mass is from cosmic rays
Above plots are from uncalibrated ToF. Calibration work is in progress.
Expected time resolution is 100 ps.
Tupper – Tlower
Run II dataRun II officially began on March 1st 2001
Started taking “physics quality” data from June 2001
Zee Z
Total Luminosity So Far
~2 week shutdown in June to install 2 new stochastic cooling tanks in the pbar accumulator, aim is to give us higher luminosity and a smaller transverse pbar beam size
Future Plans
It is hoped that approximately 50-70 pb-1 data will be collected by Summer 2002
And 150 pb-1 by end of 2002.
We hope to find new physics or set new limits using the dilepton channels.
The END
That’s All Folks!
Run 1 limits on Z' production
CDF Run II Detector
Key:
= 1.0
= 1.5
= 2.0
= 3.0ToF
Silicon TrackerFiber Tracker Drift Chamber
ScintillatorEM Cal.Hadronic Cal.
Solenoid CoilToroidSteel Shielding
CDF Upgrades for Run II New Silicon tracking System: SVX II: 5 layers, 96cm, r-phi and r-z
ISL: 2 additional layers, covers |eta| < 2
L00 :
(Addition of stereo capability to SVX, 3D Vertex and ~ 2 more acceptance)
New central drift chamber: (And strengthened COT stereo capabilities, maintain Run 1 track eff and resolution) Improved and integrated tracking system
New deadtimeless Trigger (track trigger moved to Level 1 and use Silicon info at L2)
Improved Calorimeter: resolution, efficiency and coverage
New Plug calorimeter, out to || = 2.
Extra Muon coverage
Luminosity monitor
Electronics
Higher center of mass energy
Addition of a ToF detector
ADD model
SM predictionQuantum Gravity Model for Ms valuesCDF results for dimuon samples
ADD model: Effective Planck Scale lower limit 0.9-1.5 TeV Run I (at 95% C.L.)1.3-2.5 TeV Run IIa and 1.7-3.5 TeV LHC
Range corresponds to number of extra dimensions n=7-2. (hep-ph/9909218)
Extra Dimensions
Tevatron
700 GeV KK graviton
K/MPl
Mll (GeV)
RS model
10 -2
10 -4
10 –6
10 -8
200 400 600 800 1000 1200
d/dM (pb/GeV) 1
0.70.50.30.20.1
RS model
RS model: Compactification scales R-1 (TeV) 0.9 Run 1 at 95% C.L.,
1.2 Run II, 6.7 LHC
(one large extra dimension) (hep-ph/9905311)