Download - The Known Knowns and the Known Unknowns
The Known Knowns and The Known Knowns and the Known Unknownsthe Known Unknowns
20 Years of Tevatron Collider Physics
p p CDF D0
Main Injector
TevatronBooster
p p
p source
The Tevatron c. 2006
1968 – Fermilab opens
1972 – Main Ring starts @ 400 GeV
1977 – CDF Department established
1982 – Tevatron begins operation @ 800 GeV
1985 – First Collisions at CDF
Two Hulking Detectors
CDF
D0
The World in 1985
• 3 Generations of quarks and leptons
t
e
e-
ud
cs b
Discovered at FNAL in 1977
• Electromagnetic, Weak & Strong Forces• Electroweak & Strong Forces
0, , ,W Z g
W, Z get their masses via the Higgs mechanism
3 Generations Are Needed
c ud us ub
c cd cs cb
c td ts tb
d V V V d
s V V V s
b V V V b
Particles & Antiparticles with different decay rates = CP violation d s ds
3x3 unitary matrix can be expressed with 4 parameters – 3 mixing angles + 1 complex phase
Complex phase CP Violation
In the SM all CP effects are related by this single phase.
But for 30 years, CP was only observed in
(1964 – Fitch & Cronin 1980 Nobel)
0 0K K
1983
• W±, Z0 discovered at CERN collider– MW~81±5 GeV/c2
– MZ=95.2±2.5 GeV/c2 (UA1)
– =91.9±1.9 GeV/c2 (UA2)
BS Mixing
Everything is Connected“When one tugs at a single thing in nature, he finds it attached to the rest of the world” – John Muir
Z boson
Top Quark
MW
MH
B Mixing CP
CKM
S
PBSM??
CDF December 1984
September 1985
The CDF detector (not) ready to take data:
First Collisions: October 13, 1985
Data Takingp p Protons & antiprotons
collide at ~2.5 MHz
0.25Hz of W/Z production
~100 Hz of high ET jets
~100 Hz of b-quark
production
.0002 Hz of top quark
production
?? Hz of new physics
1% “Acceptance”
~1% Analysis Mode
~10-2 Hz for analysis
10% “Acceptance”
~40% Analysis Mode
~10-5 Hz for analysis
?? “Acceptance”
?? Analysis Mode
20% “Acceptance”
~20% Analysis Mode
~10-2 Hz for analysis
Prescale/20 10%
“Acceptance”
85% to analysis
~0.4 Hz for analysis
First Precise Measurements of the Z (1989)
291.11 0.23GeV/cZM 290.9 0.36 GeV/cZM
CDFMark II at SLC
291.1876 0.0021 GeV cZM Now:
Phys. Rev. Lett. 63 (1989)0Z e
e
0Z
0Z qq
MZ
MW
W Mass
1990: CDF used 1130 W→e & 592 W→ to measure:
279.91 0.39WM GeV c
1995: 5718 W→e ; 3268 W→ 280.410 0.180WM GeV c
W e
eW
MZ
MW
W MassMW=80.433±0.079 GeV/c2
14740 events
MW=80.482±0.091 GeV/c2
11089 events
2006: MW=XX.XXX±0.049 GeV/c2 (.06%!!!)
Based on >116,000 W decays!MZ
MW
MZ
MW
2 2 2sin 1W W ZM M
0Ze
e
* e
e
These two processes interfere to produce a “forward-backward” asymmetry that depends on sin2W
1989: B0 Mixing
bW–
d
bdW+
u,c,tu,c,tB0 B0
•
•
•
•Vtd
Vtd
V*tb=1
V*tb=1
First observation in at UA1 meant the top quark was heavy
b bB hadron 0B
X X
X
0B
MTOP
B Mixing
Indirect Measurements of Mtop
t
t
0Z 0Z
MZ
MTOP
The Top Quark
• In 1990 CDF published a limit– Mtop> 77 GeV/c2
This put UA1/UA2 out of business in the search for top
• By 1992 the top non-discovery meant– Mtop>91 GeV/c2
– I.e. Mtop>MW+Mb
What We Found: 1994
• 10 events in the lepton+jets channel (5 e, 5 )
• 2 events in the di-lepton channel (both e)
• About 6 events expected from backgrounds
Not your typical event
The First Direct Measurement of Mtop
2174 16 GeV ctopM
MZ
MTOP
Discovery Top Mass GeV/c2
By 1995
• CDF: – 37 events in
lepton+jets– 6 events in
dileptons
• D0– 14 events in
lepton+jets– 3 events in
dileptons
Back-to-back papers in Phys. Rev. Lett. 74 (1995)
2176 13 GeV ctopM MZ
MTOP
2006
Mtop= 171.4 ± 2.1 GeV/c2
MZ
MTOP
MW
MH
Mtop, MW & MHiggs
2topM
t
b
W W
W WH
ln HMSoon
MTOP
MW
MH
Higgs
W Polarization in Top Decay
t
b
W+
SM says V-A2
2 21
2top
Longitudinal Left LongitudinalW top
MF F F
M M
Single Top
W*
b
tq
q
Vtb here
A very tough measurement
Top Quark
CKM
B Physics
b
CKM 1989
ud us ub
cd cs cb
td ts tb
V V V
V V V
V V V
0.9747 0.9759 0.218 0.224 0.001 0.007
0.218 0.224 0.9734 0.9752 0.030 0.058
0.003 0.019 0.029 0.058 0.9983 0.9996
Assuming 3 generation unitarity
CP Violation in B mesonsUnitarity of CKM matrix (among other things)
* * * 0ub ud cb cd tb tdV V V V V V A triangle in the complex plane (provided the CKM phase is non-zero)
*ud ubV V *
td tbV V
*cd cbV V
ccsd
t t
W
Wd0B
b /J
sK
b
d0B
W
cs
W
c
d
/J
sK
0 0
sin 2S SN B J K N B J K
All
CP
CKM
B Mixing
First Hint ≠0 (1999)
0.410.44sin 2 0.79
Now, from b factories: sin 2 0.687 0.032
Unfortunately, the SM is quite happy with this.
CP
CKM
B Mixing
BS Oscillations
bW–
s
bsW+
u,c,tu,c,tBs Bs
•
•
•
•Vts
Vts
V*tb=1
V*tb=1
Mixing Frequency is |Vts|2
CKM
BS Mixing
Matter-Antimatter Oscillations
2.8THz
ms = 17.33 +0.42 (stat) ± 0.07 (syst) ps-1
CKM
BS Mixing
CKM 2006
ud us ub
cd cs cb
td ts tb
V V V
V V V
V V V
3
3
3 3
0.97377 0.00027 0.2257 0.0021 4.31 0.30 10
0.230 0.011 0.957 0.095 41.6 0.6 10
7.4 0.8 10 40.6 2.7 10 0.9982 0.0002
Still assumes 3 generation unitarity.
BS Mixing measurement
CKM
BS Mixing
Rare Decays
bW+
sW-
tBs•
•
•
•
Vts
V*tb=1
9~ 10sBR B
Corrections from BSM physics can enhance this significantly and g-2 of the muon as well.
CDF+D0 limit BR<1.5x10-7CKM
S
PBSM?
Supersymmetry
Add this complication. Get this simplification.
PBSM??
PBSM??
Interesting Events Happen1995:
Missing Energy (GeV)
That’s interesting…PBSM??
The EggMet Event
e
01
G
Two high-energy electrons
Two high-energy photons
Large missing energy
e
e
01
e e
G
G
Nothing more through 2006…
PBSM??
BS Mixing
Everything is Connected“When one tugs at a single thing in nature, he finds it attached to the rest of the world” – John Muir
Z boson
Top Quark
MW
MH
B Mixing CP
CKM
S
PBSM??
You’re going to be told lots of things.
You get told things every day that don’t happen.
It doesn’t seem to bother people, they don’t –
It’s printed in the press.
The world thinks all these things happen.
They never happened.
Everyone’s so eager to get the story
Before in fact the story’s there
That the world is constantly being fed
Things that haven’t happened.
All I can tell you is,
It hasn’t happened.
It’s going to happen.