UCSB Top Quark Analyses On CDF
J.Lamb, C.Hill, J. Incandela, C. Mills
DOE Visit
January 20, 2004
UCSB CDF Top Group January 20, 2003, J. Incandela 2
CDF Top Quark Physics
• An interesting particle• Few events ever seen. Much to explore with higher statistics.
• Some run 1 results were a little bit provocative.
• Di-lepton channel cross-section
• Is the top quark special?t = 21/2 mt/v = 21/2 (174.1)/(246) = 1
• Top mass is an extremely important SM parameter.
• An interesting data sample• Leptons, jets, missing ET, and possibly tagged b jets
• Many of the ingredients of new physics
• We want to understand this sample well, vis-à-vis the SM
• Any discrepancies would be extremely interesting
• Relevant for LHC
• Background reference point for ttH
UCSB CDF Top Group January 20, 2003, J. Incandela 3
CDF CDF Silicon
• UCSB played well known lead roles in ISL and L00• Stuart & Incandela proposed and built ISL for slightly different motives
• Stuart – extend lepton coverage for new physics
• Incandela – extend b tagging for top, higgs and new physics
• UCSB took early advantage of the ISL for leptons
• CDF is near to taking full advantage of ISL and L00 for b tagging
UCSB CDF Top Group January 20, 2003, J. Incandela 4
CDF Top Di-lepton Cross Section
• Top cross section in Di-lepton channel• In less than one year we went from cold start to a lead role in
what will now be the first top result to be published by CDF
• Detailed in talks by Chris Hill and Corrinne Mills
• Extremely high quality analyses
• UCSB a key player
• Brought forward leptons (Phoenix) to the top group
• substantial effort
• Strong contributions helped get this measurement done in record time.
• PRL draft under review by a panel of “godparents”
UCSB CDF Top Group January 20, 2003, J. Incandela 5
CDF MW versus Mtop
W mass corrections depend on top mass (quadratically) and SM Higgs mass (logarithmically)
Run 1 Final
Tevatron Run 1 Final Measurements:
M(W)=80.456 0.059 GeV
M(t)=174.3 5.1 GeV
UCSB CDF Top Group January 20, 2003, J. Incandela 6
CDF Electroweak Prospects for 2 fb-1
With 2 fb-1:• Mw = 30 MeV/exp • Mtop = 3 GeV/exp
Tevatron upgrades:• luminosity is rising
in several years
• – (W), (Z) ~10% higher– (tt) ~ 35% higher
1-fb 2 dt L
TeV 1.96s
Detector upgrades: • increased b-jet and lepton ID acceptance and triggering
• detector performance is meeting most expectations
2 fb-1 of Run 2(per
experiment)
The UCSB top group has just begun work on the top mass
UCSB CDF Top Group January 20, 2003, J. Incandela 7
CDF A possible path to new physics ?
W & Z decay asymmetry (extending lepton ID to forward regions)
W and Z plus b & c jets
Top cross section in di-leptons + b jets
New physics searches in multi-leptonic final states
(Possibly with missing ET, b or c tags…)
Tools are complete
CDF has large data samples
UCSB playing A key role here.
UCSB top group mulling possibilities
UCSB CDF Top Group January 20, 2003, J. Incandela 8
CDF Low Mass Higgs at LHC
•Two main channels • H • ttH with H bb
• Both are challenging and could be a lot more difficult than advertised
• UCSB group will use Tevatron data to help understand ttH channel
UCSB CDF Top Group January 20, 2003, J. Incandela 9
CDF ttH without full reconstruction?
• Studied for the Tevatron
• Despite extremely low rate, could potentially dig it out from huge ttjj background by novel techniques that skirted top reconstruction
• Not expected to work as well for LHC but may gain something
• Also want to measure ttjj cross-section to calibrate LHC bkd expectations
K factor ~ 1.3 and 18% Mbb resolution
UCSB CDF Top Group January 20, 2003, J. Incandela 10
CDF Summary
• Our initial entry into top group has been very strong• First top publication: Di-lepton cross section
• Beginning new top analyses • Top mass
• Analysis of di-lepton sample
• ttjj cross-section in preparation for LHC
• Excellent synergy with CMS for students
