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 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 = 2 1/2 m t /v = 2 1/2 (174.1)/(246) = 1 Top mass is an extremely important SM parameter. An interesting data sample Leptons, jets, missing E T, 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 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 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 M W versus M top W mass corrections depend on top mass (quadratically) and SM Higgs mass (logarithmically) Run 1 Final Tevatron Run 1 Final Measurements: M(W)=  GeV M(t)=174.3  5.1 GeV

UCSB CDF Top Group January 20, 2003, J. Incandela 6 Electroweak Prospects for 2 fb -1 With 2 fb -1 :  M w = 30 MeV/exp  M top = 3 GeV/exp Tevatron upgrades: luminosity is rising in several years –  (W),  (Z) ~10% higher –  (tt) ~ 35% higher 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 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 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 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 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