Upload
merryl-blake
View
217
Download
1
Embed Size (px)
Citation preview
Recent results from theCollider Detector at Fermilab
(for the CDF collaboration)
Rob Snihur (McGill University)
CAP Congress 2007 – SaskatoonEnergy Frontier and Phenomenology I
June 19, 2007
Outline• CDF • Physics program• Higgs• Beyond the Standard Model
– MSSM Higgs – Large Extra Dimensions: Pierre-Hugues Beauchemin (this afternoon 14:15)
• Top quark– Mass: Sebastian Carron (next talk)– Production Mechanism: Shabnaz Pashapour (this session)
• QCD– Di-b-jet cross section: Greg Williams (this session)– Exclusive gamma-gamma– Z + jets
• Electroweak– W mass: William Trischuk (yesterday)– WZ production
• b physics– Bs mixing– Sigma b observation– Cascade b observation
• Summary
3
Canadian CDF institutionsUmbrella organization: IPP
• University of Alberta– Bryan Caron, Andrew Hamilton,
James Pinfold, Long Zhang
• McGill University– Adrian Buzatu, Phillipe Roy, Rob Snihur,
Andreas Warburton, Greg Williams
• University of Toronto– Hugo Beauchemin, Sebastian Caron, Dan
MacQueen, Shabnaz Pashapour, Pierre Savard, Teresa Spreitzer , Pekka Sinervo, William Trischuk
4
Tevatron
• Integrated luminosity: 3 fb-1 delivered, 2.5 fb-1 on tape• Projection: “base” = 4 fb-1, “design” = 8 fb-1
• Highest instantaneous luminosity = 292.3 x 1030
~5 interactions
5
CDF
Upgrades for Run II:– New tracking system
• COT, silicon tracker
– New forward calorimetry– Tracking at trigger level
• Tracks at L1
• Displaced from PV@L2
6
Some CDF results for Winter 2007
• QCD– b-bbar dijet production– Z+jets cross section measurement – Z b-bbar– Dijet production cross section
measurement (1.13 fb-1 )• B Physics
– Lifetime measurements:• B+, B0, Bs and B (1fb-1)
– Rare decay searches: • B++- K+, B0+- K*, Bs+-
(1fb-1)• Bhh
• Electroweak– Observation of WZ production– Evidence for ZZ production– W mass, width
• Top– Top mass in all-jets channel– Production cross section
(lepton+isolated track)– Search for W' in the single top sample– Top Production Mechanism (gg vs qq)– Top Charge
• New Phenomena– Search for Large Extra Dimensions– Search for New Particles Coupling to
Z+jets (b'->Z+b) in 1.1 fb-1
– SUSY trilepton combined limit - 0.7 to 1 fb-1
– High-mass dielectron (Z’ search) - 1.3 fb-1
• Higgs (fb-1)– H SUSY Higgs– HWW ME-based analysis – ZHllbb 2D-NN and MET fitter
analysis
7
Tevatron: close to 2 publications / week
mb -
b -
nb -
pb -
fb -
100 120 140 160 180 200
- - -
Higgs Mass [GeV/c2]
Total Inelastic
bb
WZ
tt-
-
HiggsWH,ZH
jets (qq, qg, gg)ob
serv
ed
WZ, Single Top, ZZ
MW ~0.05%
Mtop ~1%
Bs–Bs OscillationDiscovery +
Precision Meas.
MHiggs < 144 GeVat 95% CL
-
Reach 10-19 m
Low Mass SUSY
Road to the Higgs!
8
A direct path towards the Higgs
• Light or heavy Higgs?
• Strong b-tagging, large lepton coverage– X-section shows that
we must use channels with large BF (no )Production
9
Higgs searches combined
• Last update in mid March (new CDF result on WW, ZH)
10
Higgs WW• Matrix Element method• Expected background = 286.1 +- 23.3
background• Expected signal (160 GeV) = 3.9 +- 0.3• Observed 323 candidates• < 1.3 pb (95% C.L)• 10 Higgs mass hypotheses are shown
11
ZH ll bb
• Both ee & uu channels• Small background
– Mostly Z+jets
• Neural network– Discriminates event kinematics
against Z+jets & tt background
12
MSSM Higgs Tau Tau
13
Exclusive gamma gammaAndrew Hamilton, Bryan Caron, James Pinfold
(University of Alberta)
• 2 central EM showers with ET > 5 GeV
• 3 events observed, consistent with
• Background = 0.09 +- 0.04 events
• Significance = 3.7 • Cross section < 410 fb• May constrain exclusive
Higgs predictions at LHC
p
p
g
g
g
dijet, , c, Higgs
14
Z + jets
• 1.1 fb-1
• Zee
• pT(jet) > 30 GeV|y(jet)| < 2.1
• NLO agrees with data
15
First observation of WZ
Prob(background only) < 1.5 10-7 (5.1)
(WZ)=5.0+1.8-1.6(stat.+syst.)
pb
16
First observation ofBs oscillations
• PRL 97, 24003 2006• Number of Bs decays
– 5600 fully reconstructed hadronic– 3100 partially reconstructed hadronic– 61500 partially reconstructed
semileptonic
ms=17.77±0.10(stat)±0.07(syst) ps-1 > 5 effect
• Same data set used for previous (spring 06) limit
• Improved selection• Improved analysis technique
17
First observation of b
• Fully reconstructed decay modes
• Likelihood ratio (no bb states) = 2.6 x 10-19
m(Σb+) = 5808+2.0-2.3(stat.) ± 1.7(syst.) MeV/c2
m(Σb¯) = 5816+1.0-1.0(stat.) ± 1.7(syst.) MeV/c2
m(Σb*+) = 5829+1.6-1.8(stat.) ± 1.7(syst.) MeV/c2
m(Σb*¯) = 5837+2.1-1.9(stat.) ± 1.7(syst.) MeV/c2
0(*)bb
c pK
18
Observation of b
• First ~2 fb-1 analysis• Use standard decay chain
to select candidate events• Use silicon hits to track • Topology similar to
B+ J/ K+• Significance = 7.8 • Mass = 5,792.9 +- 2.4(stat)
+- 1.7(syst) MeV/c2
19
Example of Possible Fermilab Roadmap
ILC EDR + R&DILC System Test1-2 RF Units
Energy Frontier:
Beyond ILC/LHC Reach: R&D for higher energy lepton and hadron colliders
LHC LHC Upgrade
beams from Booster, Main Injector protonsMiniBooNE, SciBooNE, MINOS, MINERvA, NOvA
TevatronRunning
TevatronPhysics
Intensity Frontier: High Intensity Protons
ILC Construction
ILC Decision
ReconfiguringAccelerator
Complex
, , K, p beams
-
ILC CrymoduleIndustrialization
Running 2 GeV + 6 GeV Linac+ Recycler
+ Main InjectorRunning
20
Summary• Broad physics program at CDF
– High pT– B physics
• New results on – SM & MSSM Higgs searches– QCD
• Exclusive gamma gamma production• Z + jets
– B physics• Bs oscillations• Sigma b observation
• More results presented at this conference– W mass– Large Extra Dimensions– B jet cross section– Top quark
• Mass• Gluon-gluon vs quark quark
21
ISL Cooling: Physics Impact
• Five Layer SVX is core of system– B-tagging– Lifetime measurements– Silicon vertex triggers use SVX alone
• Layer 00– Improve vertex (eg B-tag) with point at beam pipe
• ISL– Not required for good B-tagging– High Lum point to help connect COT and SVX– High eta (||<2) tracking for forward electrons
22
Single Top
23
Tevatron Collisions• The hard scattering is not all
there is!– Parton Distribution Functions
(PDF): fraction of (anti)proton carried by incoming partons.
– Underlying Event (UE): extra stuff produce by spectator or multiple interactions.
– Initial and Final State Radiation (ISR, FSR): extra gluons radiating off the original/final partons.
– Jets: fragmentation of quark/gluons and recombination into hadrons reconstructed inside a cone.
.
All of these processes, and more, have an impact on what we measure
24
Summary
25
WH->lbb : Cut based AnalysesSingle b-tagged w/NN
CDF results:
Expect 95% C.L limit (mH =115 GeV)
< 2.2 pb (< 17 times over SM)
Observed limits:
< 3.4 pb( < 26 times over SM)
D0 results:
Expect 95% C.L limit (mH =115 GeV)
< 1.1 pb(< 9 times over SM)
Observed limits:
< 1.3 pb(< 11 times over SM)
Cross section limitRatio over SM
26
Gluino vs. squark mass exclusion
27
Chargino and Neutralino searches• Both experiments look for SUSY
signals– Chargino and neutralino are produced
with sizeable cross sections– More difficult search for squarks and
gluinos
R. Strohemer
28
Non SM Higgs
• Non SM Higgs(es) have sizeable decay rate to pairs– Large efforts to bring up efficiency to trigger
on tau events (and to detect tau)
R. Strohemer